Re: [PATCH v2 07/22] fpga: intel: pcie: parse feature list and create platform device for features.

[Wu Hao]

On Wed, Sep 20, 2017 at 04:24:10PM -0500, Alan Tull wrote:
>  a (wh., *()On Sun, Jun 25, 2017 at 8:52 PM, Wu Hao <hao.wu@xxxxxxxxx> wrote:
> 
> Hi Hao,
> 
> I'm done with some board bringup so I have time to look at your patchset again.

Hi Alan

Thanks for your time on the review. : )

> 
> Something I can't help but notice is that this patchset will be almost
> completely reusable for embedded FPGAs if the enumeration is separated
> from the pcie code.  After the devices are created, they are just mmio
> devices.  That makes this whole scheme available for embedded FPGAs.
> 
> The division of things would be that the pcie code would read the
> headers and do ioremapping.  Then pass the headers to the enumeration
> code to create the devices.  With that division, another platform that
> is embedded could have its own code that read the headers and did the
> iomapping and then used the separate enumeration code.
> 
> Going through intel-pcie.c, the truly pcie specific parts are already
> pretty well contained.  The pcie code is in probe,
> cci_pci_ioremap_bar, cci_pci_release_regions, and the 'parse_s*'
> functions that ultimately call cci_pci_ioremap_bar.  So it all comes
> down to the code that calls the 'parse_s*' functions.  That is, the
> code the reads the fme header and the port headers.  Currently, if I'm
> reading this right, this code ioremaps each region, reads its header,
> and creates its device before reading the next header.  So we just
> need to change the order a little and ioremap/read all the headers
> before starting to create devices.  That separates the pci ioremap
> from creating the devices.  So the probe function could ioremap and
> read in the fme header.  Then it would ioremap and read in each of the
> port headers.  After they are read in, then pass the all these headers
> to the separate enumeration code that will parse it and create the
> devices.  That part is not pcie specific, right?  With the enumeration
> code in a separate file (and assuming that the ioremap has already
> happened),  another platform that is embedded could have its probe do
> the iomapping and reading the headers, and then call the same
> enumeration code.

So it's suggested that we have some kind of pre-enumeration code in the
intel-pcie.c to do ioremap and locate the address of device feature lists
for FME and Ports, and hand them to common enumeration code. Is my
understanding correct?

I have considered this some time ago, this is doable for current code,
as the pre-enumeration code will be simple (only need to find FME header
and then read some register in FME header register set to locate the Port
header). But if in the future, some pcie specific things are added to some
sub features of FME, then pre-enumeration code has to parse FME and all
its sub features to handle pcie specific things. We will have more
duplicate code on pre-enumeration in intel-pcie.c and common enumeration.
Another point is, it's hard to avoid pcie specific things in sub features,
as they may be designed to use PCIE specific function or resources.
e.g some sub features require the interrupts from PCIE device, like PCIE
MSI / MSIX. So keep enumeration code away from PCI things may be difficult.

> 
> Actually, there's a bit more to it than that but I think this is
> doable.  build_info_add_sub_feature() (which is called by
> create_feature_instance) saves off resource info for each sub device.
> Does this mean this code is ioremapping again (in
> intel-fpga-fme-mgr.c's probe)?

Yes, you are correct. Is it fine to have the MMIO region mapped twice?
or we have to pass the mapped address to intel-fpga-fme-mgr directly?

> 
> A few more things below...
> 
> > From: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> >
> > Device Feature List structure creates a link list of feature headers
> > within the MMIO space to provide an extensible way of adding features.
> >
> > The Intel FPGA PCIe driver walks through the feature headers to enumerate
> > feature devices, FPGA Management Engine (FME) and FPGA Port for Accelerated
> > Function Unit (AFU), and their private sub features. For feature devices,
> > it creates the platform devices and linked the private sub features into
> > their platform data.
> >
> > Signed-off-by: Tim Whisonant <tim.whisonant@xxxxxxxxx>
> > Signed-off-by: Enno Luebbers <enno.luebbers@xxxxxxxxx>
> > Signed-off-by: Shiva Rao <shiva.rao@xxxxxxxxx>
> > Signed-off-by: Christopher Rauer <christopher.rauer@xxxxxxxxx>
> > Signed-off-by: Kang Luwei <luwei.kang@xxxxxxxxx>
> > Signed-off-by: Zhang Yi <yi.z.zhang@xxxxxxxxx>
> > Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> > Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> > ---
> > v2: moved the code to drivers/fpga folder as suggested by Alan Tull.
> >     switched to GPLv2 license.
> >     fixed comments from Moritz Fischer.
> >     fixed kbuild warning, typos and clean up the code.
> > ---
> >  drivers/fpga/Makefile            |   2 +-
> >  drivers/fpga/intel-feature-dev.c | 130 ++++++
> >  drivers/fpga/intel-feature-dev.h | 341 ++++++++++++++++
> >  drivers/fpga/intel-pcie.c        | 841 ++++++++++++++++++++++++++++++++++++++-
> >  4 files changed, 1311 insertions(+), 3 deletions(-)
> >  create mode 100644 drivers/fpga/intel-feature-dev.c
> >  create mode 100644 drivers/fpga/intel-feature-dev.h
> >
> > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> > index 5613133..ad24b3d 100644
> > --- a/drivers/fpga/Makefile
> > +++ b/drivers/fpga/Makefile
> > @@ -31,4 +31,4 @@ obj-$(CONFIG_OF_FPGA_REGION)          += of-fpga-region.o
> >  # Intel FPGA Support
> >  obj-$(CONFIG_INTEL_FPGA_PCI)           += intel-fpga-pci.o
> >
> > -intel-fpga-pci-objs := intel-pcie.o
> > +intel-fpga-pci-objs := intel-pcie.o intel-feature-dev.o
> > diff --git a/drivers/fpga/intel-feature-dev.c b/drivers/fpga/intel-feature-dev.c
> > new file mode 100644
> > index 0000000..68f9cba
> > --- /dev/null
> > +++ b/drivers/fpga/intel-feature-dev.c
> > @@ -0,0 +1,130 @@
> > +/*
> > + * Intel FPGA Feature Device Driver
> > + *
> > + * Copyright (C) 2017 Intel Corporation, Inc.
> > + *
> > + * Authors:
> > + *   Kang Luwei <luwei.kang@xxxxxxxxx>
> > + *   Zhang Yi <yi.z.zhang@xxxxxxxxx>
> > + *   Wu Hao <hao.wu@xxxxxxxxx>
> > + *   Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU GPL version 2. See
> > + * the COPYING file in the top-level directory.
> > + */
> > +
> > +#include "intel-feature-dev.h"
> > +
> > +void feature_platform_data_add(struct feature_platform_data *pdata,
> > +                              int index, const char *name,
> > +                              int resource_index, void __iomem *ioaddr)
> > +{
> > +       WARN_ON(index >= pdata->num);
> > +
> > +       pdata->features[index].name = name;
> > +       pdata->features[index].resource_index = resource_index;
> > +       pdata->features[index].ioaddr = ioaddr;
> > +}
> > +
> > +struct feature_platform_data *
> > +feature_platform_data_alloc_and_init(struct platform_device *dev, int num)
> > +{
> > +       struct feature_platform_data *pdata;
> > +
> > +       pdata = kzalloc(feature_platform_data_size(num), GFP_KERNEL);
> > +       if (pdata) {
> > +               pdata->dev = dev;
> > +               pdata->num = num;
> > +               mutex_init(&pdata->lock);
> > +       }
> > +
> > +       return pdata;
> > +}
> > +
> > +int fme_feature_num(void)
> > +{
> > +       return FME_FEATURE_ID_MAX;
> > +}
> > +
> > +int port_feature_num(void)
> > +{
> > +       return PORT_FEATURE_ID_MAX;
> > +}
> 
> Do these need to be functions?  If so, static.  But if you can just
> use the #define'd values that's one level of indirection we can get
> rid of.  And when I'm going through code where there's extra levels of
> indirection that don't do anything, it makes it harder to understand
> ;)

Sure, will fix this.

> 
> > +
> > +int fpga_port_id(struct platform_device *pdev)
> > +{
> > +       struct feature_port_header *port_hdr;
> > +       struct feature_port_capability capability;
> > +
> > +       port_hdr = get_feature_ioaddr_by_index(&pdev->dev,
> > +                                              PORT_FEATURE_ID_HEADER);
> > +       WARN_ON(!port_hdr);
> > +
> > +       capability.csr = readq(&port_hdr->capability);
> > +       return capability.port_number;
> > +}
> > +EXPORT_SYMBOL_GPL(fpga_port_id);
> 
> This is here because every feature is a port, right?

No, this fpga_port_id function will be used in both afu/port driver and
also the pcie driver, so this function in added here.
The code in pcie driver which uses this function isn't submitted yet, it's
part of the SRIOV support. The pcie driver needs to manage which port could
be turned to VF.

> 
> > +
> > +/*
> > + * Enable Port by clear the port soft reset bit, which is set by default.
> > + * The User AFU is unable to respond to any MMIO access while in reset.
> > + * __fpga_port_enable function should only be used after __fpga_port_disable
> > + * function.
> > + */
> > +void __fpga_port_enable(struct platform_device *pdev)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +       struct feature_port_header *port_hdr;
> > +       struct feature_port_control control;
> > +
> > +       WARN_ON(!pdata->disable_count);
> > +
> > +       if (--pdata->disable_count != 0)
> > +               return;
> > +
> > +       port_hdr = get_feature_ioaddr_by_index(&pdev->dev,
> > +                                              PORT_FEATURE_ID_HEADER);
> > +       WARN_ON(!port_hdr);
> > +
> > +       control.csr = readq(&port_hdr->control);
> > +       control.port_sftrst = 0x0;
> > +       writeq(control.csr, &port_hdr->control);
> > +}
> > +EXPORT_SYMBOL_GPL(__fpga_port_enable);
> > +
> > +#define RST_POLL_INVL 10 /* us */
> > +#define RST_POLL_TIMEOUT 1000 /* us */
> > +
> > +int __fpga_port_disable(struct platform_device *pdev)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +       struct feature_port_header *port_hdr;
> > +       struct feature_port_control control;
> > +
> > +       if (pdata->disable_count++ != 0)
> > +               return 0;
> > +
> > +       port_hdr = get_feature_ioaddr_by_index(&pdev->dev,
> > +                                              PORT_FEATURE_ID_HEADER);
> > +       WARN_ON(!port_hdr);
> > +
> > +       /* Set port soft reset */
> > +       control.csr = readq(&port_hdr->control);
> > +       control.port_sftrst = 0x1;
> > +       writeq(control.csr, &port_hdr->control);
> > +
> > +       /*
> > +        * HW sets ack bit to 1 when all outstanding requests have been drained
> > +        * on this port and minimum soft reset pulse width has elapsed.
> > +        * Driver polls port_soft_reset_ack to determine if reset done by HW.
> > +        */
> > +       if (readq_poll_timeout(&port_hdr->control, control.csr,
> > +                              (control.port_sftrst_ack == 1),
> > +                              RST_POLL_INVL, RST_POLL_TIMEOUT)) {
> > +               dev_err(&pdev->dev, "timeout, fail to reset device\n");
> > +               return -ETIMEDOUT;
> > +       }
> > +
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(__fpga_port_disable);
> > diff --git a/drivers/fpga/intel-feature-dev.h b/drivers/fpga/intel-feature-dev.h
> > new file mode 100644
> > index 0000000..f67784a
> > --- /dev/null
> > +++ b/drivers/fpga/intel-feature-dev.h
> > @@ -0,0 +1,341 @@
> > +/*
> > + * Intel FPGA Feature Device Driver Header File
> > + *
> > + * Copyright (C) 2017 Intel Corporation, Inc.
> > + *
> > + * Authors:
> > + *   Kang Luwei <luwei.kang@xxxxxxxxx>
> > + *   Zhang Yi <yi.z.zhang@xxxxxxxxx>
> > + *   Wu Hao <hao.wu@xxxxxxxxx>
> > + *   Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU GPL version 2. See
> > + * the COPYING file in the top-level directory.
> > + */
> > +
> > +#ifndef __INTEL_FPGA_FEATURE_H
> > +#define __INTEL_FPGA_FEATURE_H
> > +
> > +#include <linux/fs.h>
> > +#include <linux/pci.h>
> > +#include <linux/uuid.h>
> > +#include <linux/delay.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/platform_device.h>
> > +
> > +#ifndef readq
> > +static inline u64 readq(void __iomem *addr)
> > +{
> > +       return readl(addr) + ((u64)readl(addr + 4) << 32);
> > +}
> > +#endif
> > +
> > +#ifndef writeq
> > +static inline void writeq(u64 val, void __iomem *addr)
> > +{
> > +       writel((u32) (val), addr);
> > +       writel((u32) (val >> 32), (addr + 4));
> > +}
> > +#endif
> > +
> > +/* maximum supported number of ports */
> > +#define MAX_FPGA_PORT_NUM 4
> > +/* plus one for fme device */
> > +#define MAX_FEATURE_DEV_NUM    (MAX_FPGA_PORT_NUM + 1)
> > +
> > +#define FME_FEATURE_HEADER          "fme_hdr"
> > +#define FME_FEATURE_THERMAL_MGMT    "fme_thermal"
> > +#define FME_FEATURE_POWER_MGMT      "fme_power"
> > +#define FME_FEATURE_GLOBAL_PERF     "fme_gperf"
> > +#define FME_FEATURE_GLOBAL_ERR      "fme_error"
> > +#define FME_FEATURE_PR_MGMT         "fme_pr"
> > +
> > +#define PORT_FEATURE_HEADER         "port_hdr"
> > +#define PORT_FEATURE_UAFU           "port_uafu"
> > +#define PORT_FEATURE_ERR            "port_err"
> > +#define PORT_FEATURE_UMSG           "port_umsg"
> > +#define PORT_FEATURE_PR             "port_pr"
> > +#define PORT_FEATURE_STP            "port_stp"
> > +
> > +/* All headers and structures must be byte-packed to match the spec. */
> > +#pragma pack(1)
> > +
> > +/* common header for all features */
> > +struct feature_header {
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 id:12;
> > +                       u64 revision:4;
> > +                       u64 next_header_offset:24; /* offset to next header */
> > +                       u64 rsvdz:20;
> > +                       u64 type:4;                /* feature type */
> > +#define FEATURE_TYPE_AFU               0x1
> > +#define FEATURE_TYPE_PRIVATE           0x3
> > +               };
> > +       };
> > +};
> > +
> > +/* common header for non-private features */
> > +struct feature_afu_header {
> > +       uuid_le guid;
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 next_afu:24;        /* pointer to next afu header */
> > +                       u64 rsvdz:40;
> > +               };
> > +       };
> > +};
> > +
> > +/* FME Header Register Set */
> > +/* FME Capability Register */
> > +struct feature_fme_capability {
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 fabric_verid:8;     /* Fabric version ID */
> > +                       u64 socket_id:1;        /* Socket id */
> > +                       u64 rsvdz1:3;
> > +                       u64 pcie0_link_avl:1;   /* PCIe0 link availability */
> > +                       u64 pcie1_link_avl:1;   /* PCIe1 link availability */
> > +                       u64 coherent_link_avl:1;/* Coherent link availability */
> > +                       u64 rsvdz2:1;
> > +                       u64 iommu_support:1;    /* IOMMU or VT-d supported */
> > +                       u64 num_ports:3;        /* Num of ports implemented */
> > +                       u64 rsvdz3:4;
> > +                       u64 addr_width_bits:6;  /* Address width supported */
> > +                       u64 rsvdz4:2;
> > +                       u64 cache_size:12;      /* Cache size in kb */
> > +                       u64 cache_assoc:4;      /* Cache Associativity */
> > +                       u64 rsvdz5:15;
> > +                       u64 lock_bit:1;         /* Latched lock bit by BIOS */
> > +               };
> > +       };
> > +};
> > +
> > +/* FME Port Offset Register */
> > +struct feature_fme_port {
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 port_offset:24;     /* Offset to port header */
> > +                       u64 rsvdz1:8;
> > +                       u64 port_bar:3;         /* Bar id */
> > +                       u64 rsvdz2:20;
> > +                       u64 afu_access_ctrl:1;  /* AFU access type: PF/VF */
> > +                       u64 rsvdz3:4;
> > +                       u64 port_implemented:1; /* Port implemented or not */
> > +                       u64 rsvdz4:3;
> > +               };
> > +       };
> > +};
> > +
> > +struct feature_fme_header {
> > +       struct feature_header header;
> > +       struct feature_afu_header afu_header;
> > +       u64 rsvd[2];
> > +       struct feature_fme_capability capability;
> > +       struct feature_fme_port port[MAX_FPGA_PORT_NUM];
> > +};
> > +
> > +/* FME Thermal Sub Feature Register Set */
> > +struct feature_fme_thermal {
> > +       struct feature_header header;
> > +};
> > +
> > +/* FME Power Sub Feature Register Set */
> > +struct feature_fme_power {
> > +       struct feature_header header;
> > +};
> > +
> > +/* FME Global Performance Sub Feature Register Set */
> > +struct feature_fme_gperf {
> > +       struct feature_header header;
> > +};
> > +
> > +/* FME Error Sub Feature Register Set */
> > +struct feature_fme_err {
> > +       struct feature_header header;
> > +};
> > +
> > +/* FME Partial Reconfiguration Sub Feature Register Set */
> > +struct feature_fme_pr {
> > +       struct feature_header header;
> > +};
> > +
> > +/* PORT Header Register Set */
> > +/* Port Capability Register */
> > +struct feature_port_capability {
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 port_number:2;      /* Port Number 0-3 */
> > +                       u64 rsvdz1:6;
> > +                       u64 mmio_size:16;       /* User MMIO size in KB */
> > +                       u64 rsvdz2:8;
> > +                       u64 sp_intr_num:4;      /* Supported interrupts num */
> > +                       u64 rsvdz3:28;
> > +               };
> > +       };
> > +};
> > +
> > +/* Port Control Register */
> > +struct feature_port_control {
> > +       union {
> > +               u64 csr;
> > +               struct {
> > +                       u64 port_sftrst:1;      /* Port Soft Reset */
> > +                       u64 rsvdz1:1;
> > +                       u64 latency_tolerance:1;/* '1' >= 40us, '0' < 40us */
> > +                       u64 rsvdz2:1;
> > +                       u64 port_sftrst_ack:1;  /* HW ACK for Soft Reset */
> > +                       u64 rsvdz3:59;
> > +               };
> > +       };
> > +};
> > +
> > +struct feature_port_header {
> > +       struct feature_header header;
> > +       struct feature_afu_header afu_header;
> > +       u64 rsvd[2];
> > +       struct feature_port_capability capability;
> > +       struct feature_port_control control;
> > +};
> > +
> > +/* PORT Error Sub Feature Register Set */
> > +struct feature_port_error {
> > +       struct feature_header header;
> > +};
> > +
> > +/* PORT Unordered Message Sub Feature Register Set */
> > +struct feature_port_umsg {
> > +       struct feature_header header;
> > +};
> > +
> > +/* PORT SignalTap Sub Feature Register Set */
> > +struct feature_port_stp {
> > +       struct feature_header header;
> > +};
> > +
> > +#pragma pack()
> > +
> > +struct feature {
> > +       const char *name;
> > +       int resource_index;
> > +       void __iomem *ioaddr;
> > +};
> > +
> > +struct feature_platform_data {
> > +       /* list the feature dev to cci_drvdata->port_dev_list. */
> > +       struct list_head node;
> > +       struct mutex lock;
> > +       struct platform_device *dev;
> > +       unsigned int disable_count;     /* count for port disable */
> > +
> > +       int num;                        /* number of features */
> > +       struct feature features[0];
> > +};
> > +
> > +enum fme_feature_id {
> > +       FME_FEATURE_ID_HEADER = 0x0,
> > +       FME_FEATURE_ID_THERMAL_MGMT = 0x1,
> > +       FME_FEATURE_ID_POWER_MGMT = 0x2,
> > +       FME_FEATURE_ID_GLOBAL_PERF = 0x3,
> > +       FME_FEATURE_ID_GLOBAL_ERR = 0x4,
> > +       FME_FEATURE_ID_PR_MGMT = 0x5,
> > +       FME_FEATURE_ID_MAX = 0x6,
> > +};
> > +
> > +enum port_feature_id {
> > +       PORT_FEATURE_ID_HEADER = 0x0,
> > +       PORT_FEATURE_ID_ERROR = 0x1,
> > +       PORT_FEATURE_ID_UMSG = 0x2,
> > +       PORT_FEATURE_ID_PR = 0x3,
> > +       PORT_FEATURE_ID_STP = 0x4,
> > +       PORT_FEATURE_ID_UAFU = 0x5,
> > +       PORT_FEATURE_ID_MAX = 0x6,
> > +};
> > +
> > +int fme_feature_num(void);
> > +int port_feature_num(void);
> > +
> > +#define FPGA_FEATURE_DEV_FME           "intel-fpga-fme"
> > +#define FPGA_FEATURE_DEV_PORT          "intel-fpga-port"
> > +
> > +void feature_platform_data_add(struct feature_platform_data *pdata,
> > +                              int index, const char *name,
> > +                              int resource_index, void __iomem *ioaddr);
> > +
> > +static inline int feature_platform_data_size(const int num)
> > +{
> > +       return sizeof(struct feature_platform_data) +
> > +               num * sizeof(struct feature);
> > +}
> > +
> > +struct feature_platform_data *
> > +feature_platform_data_alloc_and_init(struct platform_device *dev, int num);
> > +
> > +int fpga_port_id(struct platform_device *pdev);
> > +
> > +static inline int fpga_port_check_id(struct platform_device *pdev,
> > +                                    void *pport_id)
> > +{
> > +       return fpga_port_id(pdev) == *(int *)pport_id;
> > +}
> > +
> > +void __fpga_port_enable(struct platform_device *pdev);
> > +int __fpga_port_disable(struct platform_device *pdev);
> > +
> > +static inline void fpga_port_enable(struct platform_device *pdev)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +
> > +       mutex_lock(&pdata->lock);
> > +       __fpga_port_enable(pdev);
> > +       mutex_unlock(&pdata->lock);
> > +}
> > +
> > +static inline int fpga_port_disable(struct platform_device *pdev)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +       int ret;
> > +
> > +       mutex_lock(&pdata->lock);
> > +       ret = __fpga_port_disable(pdev);
> > +       mutex_unlock(&pdata->lock);
> > +
> > +       return ret;
> > +}
> > +
> > +static inline int __fpga_port_reset(struct platform_device *pdev)
> > +{
> > +       int ret;
> > +
> > +       ret = __fpga_port_disable(pdev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       __fpga_port_enable(pdev);
> > +       return 0;
> > +}
> > +
> > +static inline int fpga_port_reset(struct platform_device *pdev)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +       int ret;
> > +
> > +       mutex_lock(&pdata->lock);
> > +       ret = __fpga_port_reset(pdev);
> > +       mutex_unlock(&pdata->lock);
> > +       return ret;
> > +}
> > +
> > +static inline void __iomem *
> > +get_feature_ioaddr_by_index(struct device *dev, int index)
> > +{
> > +       struct feature_platform_data *pdata = dev_get_platdata(dev);
> > +
> > +       return pdata->features[index].ioaddr;
> > +}
> > +#endif
> > diff --git a/drivers/fpga/intel-pcie.c b/drivers/fpga/intel-pcie.c
> > index f697de4..70b8284 100644
> > --- a/drivers/fpga/intel-pcie.c
> > +++ b/drivers/fpga/intel-pcie.c
> > @@ -23,10 +23,827 @@
> >  #include <linux/stddef.h>
> >  #include <linux/errno.h>
> >  #include <linux/aer.h>
> > +#include <linux/fpga/fpga-dev.h>
> > +
> > +#include "intel-feature-dev.h"
> >
> >  #define DRV_VERSION    "0.8"
> >  #define DRV_NAME       "intel-fpga-pci"
> >
> > +#define INTEL_FPGA_DEV "intel-fpga-dev"
> > +
> > +static DEFINE_MUTEX(fpga_id_mutex);
> > +
> > +enum fpga_id_type {
> > +       FME_ID,         /* fme id allocation and mapping */
> > +       PORT_ID,        /* port id allocation and mapping */
> > +       FPGA_ID_MAX,
> > +};
> > +
> > +/* it is protected by fpga_id_mutex */
> > +static struct idr fpga_ids[FPGA_ID_MAX];
> > +
> > +struct cci_drvdata {
> > +       struct device *fme_dev;
> > +
> > +       struct mutex lock;
> > +       struct list_head port_dev_list;
> > +
> > +       struct list_head regions; /* global list of pci bar mapping region */
> > +};
> > +
> > +/* pci bar mapping info */
> > +struct cci_pci_region {
> > +       int bar;
> > +       void __iomem *ioaddr;   /* pointer to mapped bar region */
> > +       struct list_head node;
> > +};
> > +
> > +static void fpga_ids_init(void)
> > +{
> > +       int i;
> > +
> > +       for (i = 0; i < ARRAY_SIZE(fpga_ids); i++)
> > +               idr_init(fpga_ids + i);
> > +}
> > +
> > +static void fpga_ids_destroy(void)
> > +{
> > +       int i;
> > +
> > +       for (i = 0; i < ARRAY_SIZE(fpga_ids); i++)
> > +               idr_destroy(fpga_ids + i);
> > +}
> > +
> > +static int alloc_fpga_id(enum fpga_id_type type, struct device *dev)
> > +{
> > +       int id;
> > +
> > +       WARN_ON(type >= FPGA_ID_MAX);
> > +       mutex_lock(&fpga_id_mutex);
> > +       id = idr_alloc(fpga_ids + type, dev, 0, 0, GFP_KERNEL);
> > +       mutex_unlock(&fpga_id_mutex);
> > +       return id;
> > +}
> > +
> > +static void free_fpga_id(enum fpga_id_type type, int id)
> > +{
> > +       WARN_ON(type >= FPGA_ID_MAX);
> > +       mutex_lock(&fpga_id_mutex);
> > +       idr_remove(fpga_ids + type, id);
> > +       mutex_unlock(&fpga_id_mutex);
> > +}
> > +
> > +static void cci_pci_add_port_dev(struct pci_dev *pdev,
> > +                                struct platform_device *port_dev)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
> > +       struct feature_platform_data *pdata = dev_get_platdata(&port_dev->dev);
> > +
> > +       mutex_lock(&drvdata->lock);
> > +       list_add(&pdata->node, &drvdata->port_dev_list);
> > +       get_device(&pdata->dev->dev);
> > +       mutex_unlock(&drvdata->lock);
> > +}
> > +
> > +static void cci_pci_remove_port_devs(struct pci_dev *pdev)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
> > +       struct feature_platform_data *pdata, *ptmp;
> > +
> > +       mutex_lock(&drvdata->lock);
> > +       list_for_each_entry_safe(pdata, ptmp, &drvdata->port_dev_list, node) {
> > +               struct platform_device *port_dev = pdata->dev;
> > +
> > +               /* the port should be unregistered first. */
> > +               WARN_ON(device_is_registered(&port_dev->dev));
> > +               list_del(&pdata->node);
> > +               free_fpga_id(PORT_ID, port_dev->id);
> > +               put_device(&port_dev->dev);
> > +       }
> > +       mutex_unlock(&drvdata->lock);
> > +}
> > +
> > +/* info collection during feature dev build. */
> > +struct build_feature_devs_info {
> > +       struct pci_dev *pdev;
> > +
> > +       /*
> > +        * PCI BAR mapping info. Parsing feature list starts from
> > +        * BAR 0 and switch to different BARs to parse Port
> > +        */
> > +       void __iomem *ioaddr;
> > +       void __iomem *ioend;
> > +       int current_bar;
> > +
> > +       /* points to FME header where the port offset is figured out. */
> > +       void __iomem *pfme_hdr;
> > +
> > +       /* the container device for all feature devices */
> > +       struct fpga_dev *parent_dev;
> > +
> > +       /* current feature device */
> > +       struct platform_device *feature_dev;
> > +};
> > +
> > +static void cci_pci_release_regions(struct pci_dev *pdev)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
> > +       struct cci_pci_region *tmp, *region;
> > +
> > +       list_for_each_entry_safe(region, tmp, &drvdata->regions, node) {
> > +               list_del(&region->node);
> > +               if (region->ioaddr)
> > +                       pci_iounmap(pdev, region->ioaddr);
> > +               devm_kfree(&pdev->dev, region);
> > +       }
> > +}
> > +
> > +static void __iomem *cci_pci_ioremap_bar(struct pci_dev *pdev, int bar)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
> > +       struct cci_pci_region *region;
> > +
> > +       list_for_each_entry(region, &drvdata->regions, node)
> > +               if (region->bar == bar) {
> > +                       dev_dbg(&pdev->dev, "BAR %d region exists\n", bar);
> > +                       return region->ioaddr;
> > +               }
> > +
> > +       region = devm_kzalloc(&pdev->dev, sizeof(*region), GFP_KERNEL);
> > +       if (!region)
> > +               return NULL;
> > +
> > +       region->bar = bar;
> > +       region->ioaddr = pci_ioremap_bar(pdev, bar);
> > +       if (!region->ioaddr) {
> > +               dev_err(&pdev->dev, "can't ioremap memory from BAR %d.\n", bar);
> > +               devm_kfree(&pdev->dev, region);
> > +               return NULL;
> > +       }
> > +
> > +       list_add(&region->node, &drvdata->regions);
> > +       return region->ioaddr;
> > +}
> > +
> > +static int parse_start_from(struct build_feature_devs_info *binfo, int bar)
> > +{
> > +       binfo->ioaddr = cci_pci_ioremap_bar(binfo->pdev, bar);
> > +       if (!binfo->ioaddr)
> > +               return -ENOMEM;
> > +
> > +       binfo->current_bar = bar;
> > +       binfo->ioend = binfo->ioaddr + pci_resource_len(binfo->pdev, bar);
> > +       return 0;
> > +}
> > +
> > +static int parse_start(struct build_feature_devs_info *binfo)
> > +{
> > +       /* fpga feature list starts from BAR 0 */
> > +       return parse_start_from(binfo, 0);
> > +}
> > +
> > +/* switch the memory mapping to BAR# @bar */
> > +static int parse_switch_to(struct build_feature_devs_info *binfo, int bar)
> > +{
> > +       return parse_start_from(binfo, bar);
> > +}
> 
> parse_switch_to() and parse_start() are both one line wrappers for
> parse_start_from() and are only called once.  :-) Please just use
> parse_start_from and get rid of parse_start and parse_switch_to.  I
> don't think this code is all that super complicated.  But as I'm
> grepping through this code, I'm trying to see all the places that do
> the same thing; if I have to look for multiple function names, it
> takes longer to get what is going on here.
> 
> Actually, cci_pci_ioremap_bar is only called in one place -
> parse_start_from - which really just adds two lines of code.
> parse_start_from could go away.  Just a suggestion.  The reason this
> comes up is that cci_pci_ioremap_bar is the more descriptive function
> name.  The parse_start/switch function names hide the biggest thing
> they do, which is ioremapping.  They don't actually do any parsing ;)

I think I need to explain a little more on the enumeration steps in this
cci_pci_create_feature_devs function, and we use these names for these
functions.

1) parse_start -> that initializes the enumeration from PCI Bar0.
   In PF case, the first byte of BAR0, will be FME header.
   In VF case, the first byte of BAR0, will be Port header.
   (FME module is always in PF, no FME module in VF).

2) parse_feature_list -> parse one device feature list

   This function parses a feature list, it could be FME device feature
   list (PF) or Port device feature list (VF).
   FME device feature list and Port device feature list are not linked
   together, as they are in differnet BARs.

3) parse_port_from_fme -> parse Port device feature lists if FME presents.

   If FME is detected (PF), read FME registers to know the location (BAR n
   + offset) of each port's header (port device feature list).
   call parse_switch_to(BAR n) and call parse_feature_list to parse the
   port device feature list.

   If FME is not detected (VF), just do nothing.

Do you think if we could keep these functions? We use these names to
help people to understand the enumeration process better, but looks like
I should add more descriptions/comments here to avoid misunderstanding. :)

> 
> > +
> > +static struct build_feature_devs_info *
> > +build_info_alloc_and_init(struct pci_dev *pdev)
> > +{
> > +       struct build_feature_devs_info *binfo;
> > +
> > +       binfo = devm_kzalloc(&pdev->dev, sizeof(*binfo), GFP_KERNEL);
> > +       if (binfo)
> > +               binfo->pdev = pdev;
> 
> build_info_alloc_and_init() is only doing a devm_kzalloc and is only
> called once.  The code would be more readable if you just had the
> devm_kzalloc in the function that called this
> (cci_pci_create_feature_devs).

Sure.

> 
> > +
> > +       return binfo;
> > +}
> > +
> > +static enum fpga_id_type feature_dev_id_type(struct platform_device *pdev)
> > +{
> > +       if (!strcmp(pdev->name, FPGA_FEATURE_DEV_FME))
> > +               return FME_ID;
> > +
> > +       if (!strcmp(pdev->name, FPGA_FEATURE_DEV_PORT))
> > +               return PORT_ID;
> > +
> > +       WARN_ON(1);
> > +       return FPGA_ID_MAX;
> > +}
> > +
> > +/*
> > + * register current feature device, it is called when we need to switch to
> > + * another feature parsing or we have parsed all features
> > + */
> > +static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> > +{
> > +       int ret;
> > +
> > +       if (!binfo->feature_dev)
> > +               return 0;
> > +
> > +       ret = platform_device_add(binfo->feature_dev);
> > +       if (!ret) {
> > +               struct cci_drvdata *drvdata;
> > +
> > +               drvdata = dev_get_drvdata(&binfo->pdev->dev);
> > +               if (feature_dev_id_type(binfo->feature_dev) == PORT_ID)
> > +                       cci_pci_add_port_dev(binfo->pdev, binfo->feature_dev);
> > +               else
> > +                       drvdata->fme_dev = get_device(&binfo->feature_dev->dev);
> > +
> > +               /*
> > +                * reset it to avoid build_info_free() freeing their resource.
> > +                *
> > +                * The resource of successfully registered feature devices
> > +                * will be freed by platform_device_unregister(). See the
> > +                * comments in build_info_create_dev().
> > +                */
> > +               binfo->feature_dev = NULL;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +static int
> > +build_info_create_dev(struct build_feature_devs_info *binfo,
> > +                     enum fpga_id_type type, int feature_nr, const char *name)
> > +{
> > +       struct platform_device *fdev;
> > +       struct resource *res;
> > +       struct feature_platform_data *pdata;
> > +       int ret;
> > +
> > +       /* we will create a new device, commit current device first */
> > +       ret = build_info_commit_dev(binfo);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * we use -ENODEV as the initialization indicator which indicates
> > +        * whether the id need to be reclaimed
> > +        */
> > +       fdev = binfo->feature_dev = platform_device_alloc(name, -ENODEV);
> > +       if (!fdev)
> > +               return -ENOMEM;
> > +
> > +       fdev->id = alloc_fpga_id(type, &fdev->dev);
> > +       if (fdev->id < 0)
> > +               return fdev->id;
> > +
> > +       fdev->dev.parent = &binfo->parent_dev->dev;
> > +
> > +       /*
> > +        * we do not need to care for the memory which is associated with
> > +        * the platform device. After calling platform_device_unregister(),
> > +        * it will be automatically freed by device's release() callback,
> > +        * platform_device_release().
> > +        */
> > +       pdata = feature_platform_data_alloc_and_init(fdev, feature_nr);
> > +       if (!pdata)
> > +               return -ENOMEM;
> > +
> > +       /*
> > +        * the count should be initialized to 0 to make sure
> > +        *__fpga_port_enable() following __fpga_port_disable()
> > +        * works properly for port device.
> > +        * and it should always be 0 for fme device.
> > +        */
> > +       WARN_ON(pdata->disable_count);
> > +
> > +       fdev->dev.platform_data = pdata;
> > +       fdev->num_resources = feature_nr;
> > +       fdev->resource = kcalloc(feature_nr, sizeof(*res), GFP_KERNEL);
> > +       if (!fdev->resource)
> > +               return -ENOMEM;
> > +
> > +       return 0;
> > +}
> > +
> > +static int remove_feature_dev(struct device *dev, void *data)
> > +{
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +
> > +       platform_device_unregister(pdev);
> > +       return 0;
> > +}
> > +
> > +static int remove_parent_dev(struct device *dev, void *data)
> > +{
> > +       /* remove platform devices attached in the parent device */
> > +       device_for_each_child(dev, NULL, remove_feature_dev);
> > +       fpga_dev_destroy(to_fpga_dev(dev));
> > +       return 0;
> > +}
> > +
> > +static void remove_all_devs(struct pci_dev *pdev)
> > +{
> > +       /* remove parent device and all its children. */
> > +       device_for_each_child(&pdev->dev, NULL, remove_parent_dev);
> > +}
> > +
> > +static void build_info_free(struct build_feature_devs_info *binfo)
> > +{
> > +       if (!IS_ERR_OR_NULL(binfo->parent_dev))
> > +               remove_all_devs(binfo->pdev);
> > +
> > +       /*
> > +        * it is a valid id, free it. See comments in
> > +        * build_info_create_dev()
> > +        */
> > +       if (binfo->feature_dev && binfo->feature_dev->id >= 0)
> > +               free_fpga_id(feature_dev_id_type(binfo->feature_dev),
> > +                            binfo->feature_dev->id);
> > +
> > +       platform_device_put(binfo->feature_dev);
> > +
> > +       devm_kfree(&binfo->pdev->dev, binfo);
> > +}
> > +
> > +#define FEATURE_TYPE_AFU       0x1
> > +#define FEATURE_TYPE_PRIVATE   0x3
> > +
> > +/* FME and PORT GUID are fixed */
> > +#define FEATURE_FME_GUID "f9e17764-38f0-82fe-e346-524ae92aafbf"
> > +#define FEATURE_PORT_GUID "6b355b87-b06c-9642-eb42-8d139398b43a"
> > +
> > +static bool feature_is_fme(struct feature_afu_header *afu_hdr)
> > +{
> > +       uuid_le u;
> > +
> > +       uuid_le_to_bin(FEATURE_FME_GUID, &u);
> > +
> > +       return !uuid_le_cmp(u, afu_hdr->guid);
> > +}
> > +
> > +static bool feature_is_port(struct feature_afu_header *afu_hdr)
> > +{
> > +       uuid_le u;
> > +
> > +       uuid_le_to_bin(FEATURE_PORT_GUID, &u);
> > +
> > +       return !uuid_le_cmp(u, afu_hdr->guid);
> > +}
> > +
> > +/*
> > + * UAFU GUID is dynamic as it can be changed after FME downloads different
> > + * Green Bitstream to the port, so we treat the unknown GUIDs which are
> > + * attached on port's feature list as UAFU.
> > + */
> > +static bool feature_is_UAFU(struct build_feature_devs_info *binfo)
> > +{
> > +       if (!binfo->feature_dev ||
> > +             feature_dev_id_type(binfo->feature_dev) != PORT_ID)
> > +               return false;
> > +
> > +       return true;
> > +}
> > +
> > +static void
> > +build_info_add_sub_feature(struct build_feature_devs_info *binfo,
> > +                          int feature_id, const char *feature_name,
> > +                          resource_size_t resource_size, void __iomem *start)
> > +{
> > +
> > +       struct platform_device *fdev = binfo->feature_dev;
> > +       struct feature_platform_data *pdata = dev_get_platdata(&fdev->dev);
> > +       struct resource *res = &fdev->resource[feature_id];
> > +
> > +       res->start = pci_resource_start(binfo->pdev, binfo->current_bar) +
> > +               start - binfo->ioaddr;
> > +       res->end = res->start + resource_size - 1;
> > +       res->flags = IORESOURCE_MEM;
> > +       res->name = feature_name;
> > +
> > +       feature_platform_data_add(pdata, feature_id,
> > +                                 feature_name, feature_id, start);
> > +}
> > +
> > +struct feature_info {
> > +       const char *name;
> > +       resource_size_t resource_size;
> > +       int feature_index;
> > +};
> > +
> > +/* indexed by fme feature IDs which are defined in 'enum fme_feature_id'. */
> > +static struct feature_info fme_features[] = {
> > +       {
> > +               .name = FME_FEATURE_HEADER,
> > +               .resource_size = sizeof(struct feature_fme_header),
> > +               .feature_index = FME_FEATURE_ID_HEADER,
> > +       },
> > +       {
> > +               .name = FME_FEATURE_THERMAL_MGMT,
> > +               .resource_size = sizeof(struct feature_fme_thermal),
> > +               .feature_index = FME_FEATURE_ID_THERMAL_MGMT,
> > +       },
> > +       {
> > +               .name = FME_FEATURE_POWER_MGMT,
> > +               .resource_size = sizeof(struct feature_fme_power),
> > +               .feature_index = FME_FEATURE_ID_POWER_MGMT,
> > +       },
> > +       {
> > +               .name = FME_FEATURE_GLOBAL_PERF,
> > +               .resource_size = sizeof(struct feature_fme_gperf),
> > +               .feature_index = FME_FEATURE_ID_GLOBAL_PERF,
> > +       },
> > +       {
> > +               .name = FME_FEATURE_GLOBAL_ERR,
> > +               .resource_size = sizeof(struct feature_fme_err),
> > +               .feature_index = FME_FEATURE_ID_GLOBAL_ERR,
> > +       },
> > +       {
> > +               .name = FME_FEATURE_PR_MGMT,
> > +               .resource_size = sizeof(struct feature_fme_pr),
> > +               .feature_index = FME_FEATURE_ID_PR_MGMT,
> > +       }
> > +};
> > +
> > +/* indexed by port feature IDs which are defined in 'enum port_feature_id'. */
> > +static struct feature_info port_features[] = {
> > +       {
> > +               .name = PORT_FEATURE_HEADER,
> > +               .resource_size = sizeof(struct feature_port_header),
> > +               .feature_index = PORT_FEATURE_ID_HEADER,
> > +       },
> > +       {
> > +               .name = PORT_FEATURE_ERR,
> > +               .resource_size = sizeof(struct feature_port_error),
> > +               .feature_index = PORT_FEATURE_ID_ERROR,
> > +       },
> > +       {
> > +               .name = PORT_FEATURE_UMSG,
> > +               .resource_size = sizeof(struct feature_port_umsg),
> > +               .feature_index = PORT_FEATURE_ID_UMSG,
> > +       },
> > +       {
> > +               /* This feature isn't available for now */
> > +               .name = PORT_FEATURE_PR,
> > +               .resource_size = 0,
> > +               .feature_index = PORT_FEATURE_ID_PR,
> > +       },
> > +       {
> > +               .name = PORT_FEATURE_STP,
> > +               .resource_size = sizeof(struct feature_port_stp),
> > +               .feature_index = PORT_FEATURE_ID_STP,
> > +       },
> > +       {
> > +               /*
> > +                * For User AFU feature, its region size is not fixed, but
> > +                * reported by register PortCapability.mmio_size. Resource
> > +                * size of UAFU will be set while parse port device.
> > +                */
> > +               .name = PORT_FEATURE_UAFU,
> > +               .resource_size = 0,
> > +               .feature_index = PORT_FEATURE_ID_UAFU,
> > +       },
> > +};
> > +
> > +static int
> > +create_feature_instance(struct build_feature_devs_info *binfo,
> > +                       void __iomem *start, struct feature_info *finfo)
> > +{
> > +       if (binfo->ioend - start < finfo->resource_size)
> > +               return -EINVAL;
> > +
> > +       build_info_add_sub_feature(binfo, finfo->feature_index, finfo->name,
> > +                                  finfo->resource_size, start);
> > +       return 0;
> > +}
> 
> build_info_add_sub_feature() is only called one time - here.  Could
> you collapse these two functions together?

Sure.

> 
> > +
> > +static int parse_feature_fme(struct build_feature_devs_info *binfo,
> > +                            void __iomem *start)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&binfo->pdev->dev);
> > +       int ret;
> > +
> > +       ret = build_info_create_dev(binfo, FME_ID, fme_feature_num(),
> > +                                       FPGA_FEATURE_DEV_FME);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (drvdata->fme_dev) {
> > +               dev_err(&binfo->pdev->dev, "Multiple FMEs are detected.\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       return create_feature_instance(binfo, start,
> > +                                      &fme_features[FME_FEATURE_ID_HEADER]);
> > +}
> > +
> > +static int parse_feature_fme_private(struct build_feature_devs_info *binfo,
> > +                                    struct feature_header *hdr)
> > +{
> > +       struct feature_header header;
> > +
> > +       header.csr = readq(hdr);
> > +
> > +       if (header.id >= ARRAY_SIZE(fme_features)) {
> > +               dev_info(&binfo->pdev->dev, "FME feature id %x is not supported yet.\n",
> > +                        header.id);
> > +               return 0;
> > +       }
> > +
> > +       return create_feature_instance(binfo, hdr, &fme_features[header.id]);
> > +}
> > +
> > +static int parse_feature_port(struct build_feature_devs_info *binfo,
> > +                            void __iomem *start)
> > +{
> > +       int ret;
> > +
> > +       ret = build_info_create_dev(binfo, PORT_ID, port_feature_num(),
> > +                                       FPGA_FEATURE_DEV_PORT);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return create_feature_instance(binfo, start,
> > +                                      &port_features[PORT_FEATURE_ID_HEADER]);
> > +}
> > +
> > +static void enable_port_uafu(struct build_feature_devs_info *binfo,
> > +                            void __iomem *start)
> > +{
> > +       enum port_feature_id id = PORT_FEATURE_ID_UAFU;
> > +       struct feature_port_header *port_hdr;
> > +       struct feature_port_capability capability;
> > +
> > +       port_hdr = (struct feature_port_header *)start;
> > +       capability.csr = readq(&port_hdr->capability);
> > +       port_features[id].resource_size = capability.mmio_size << 10;
> > +
> > +       /*
> > +        * To enable User AFU, driver needs to clear reset bit on related port,
> > +        * otherwise the mmio space of this user AFU will be invalid.
> > +        */
> > +       if (port_features[id].resource_size)
> > +               fpga_port_reset(binfo->feature_dev);
> > +}
> > +
> > +static int parse_feature_port_private(struct build_feature_devs_info *binfo,
> > +                                     struct feature_header *hdr)
> > +{
> > +       struct feature_header header;
> > +       enum port_feature_id id;
> > +
> > +       header.csr = readq(hdr);
> > +       /*
> > +        * the region of port feature id is [0x10, 0x13], + 1 to reserve 0
> > +        * which is dedicated for port-hdr.
> > +        */
> > +       id = (header.id & 0x000f) + 1;
> > +
> > +       if (id >= ARRAY_SIZE(port_features)) {
> > +               dev_info(&binfo->pdev->dev, "Port feature id %x is not supported yet.\n",
> > +                        header.id);
> > +               return 0;
> > +       }
> > +
> > +       return create_feature_instance(binfo, hdr, &port_features[id]);
> > +}
> > +
> > +static int parse_feature_port_uafu(struct build_feature_devs_info *binfo,
> > +                                struct feature_header *hdr)
> > +{
> > +       enum port_feature_id id = PORT_FEATURE_ID_UAFU;
> > +       int ret;
> > +
> > +       if (port_features[id].resource_size) {
> > +               ret = create_feature_instance(binfo, hdr, &port_features[id]);
> > +               port_features[id].resource_size = 0;
> > +       } else {
> > +               dev_err(&binfo->pdev->dev, "the uafu feature header is mis-configured.\n");
> > +               ret = -EINVAL;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +static int parse_feature_afus(struct build_feature_devs_info *binfo,
> > +                             struct feature_header *hdr)
> > +{
> > +       int ret;
> > +       struct feature_afu_header *afu_hdr, header;
> > +       void __iomem *start;
> > +       void __iomem *end = binfo->ioend;
> > +
> > +       start = hdr;
> > +       for (; start < end; start += header.next_afu) {
> > +               if (end - start < (sizeof(*afu_hdr) + sizeof(*hdr)))
> > +                       return -EINVAL;
> > +
> > +               hdr = start;
> > +               afu_hdr = (struct feature_afu_header *) (hdr + 1);
> > +               header.csr = readq(&afu_hdr->csr);
> > +
> > +               if (feature_is_fme(afu_hdr)) {
> > +                       ret = parse_feature_fme(binfo, hdr);
> > +                       binfo->pfme_hdr = hdr;
> > +                       if (ret)
> > +                               return ret;
> > +               } else if (feature_is_port(afu_hdr)) {
> > +                       ret = parse_feature_port(binfo, hdr);
> > +                       enable_port_uafu(binfo, hdr);
> > +                       if (ret)
> > +                               return ret;
> > +               } else if (feature_is_UAFU(binfo)) {
> > +                       ret = parse_feature_port_uafu(binfo, hdr);
> > +                       if (ret)
> > +                               return ret;
> > +               } else
> > +                       dev_info(&binfo->pdev->dev, "AFU GUID %pUl is not supported yet.\n",
> > +                                afu_hdr->guid.b);
> > +
> > +               if (!header.next_afu)
> > +                       break;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int parse_feature_private(struct build_feature_devs_info *binfo,
> > +                                struct feature_header *hdr)
> > +{
> > +       struct feature_header header;
> > +
> > +       header.csr = readq(hdr);
> > +
> > +       if (!binfo->feature_dev) {
> > +               dev_err(&binfo->pdev->dev, "the private feature %x does not belong to any AFU.\n",
> > +                       header.id);
> > +               return -EINVAL;
> > +       }
> > +
> > +       switch (feature_dev_id_type(binfo->feature_dev)) {
> > +       case FME_ID:
> > +               return parse_feature_fme_private(binfo, hdr);
> > +       case PORT_ID:
> > +               return parse_feature_port_private(binfo, hdr);
> > +       default:
> > +               dev_info(&binfo->pdev->dev, "private feature %x belonging to AFU %s is not supported yet.\n",
> > +                        header.id, binfo->feature_dev->name);
> > +       }
> > +       return 0;
> > +}
> > +
> > +static int parse_feature(struct build_feature_devs_info *binfo,
> > +                        struct feature_header *hdr)
> > +{
> > +       struct feature_header header;
> > +       int ret = 0;
> > +
> > +       header.csr = readq(hdr);
> > +
> > +       switch (header.type) {
> > +       case FEATURE_TYPE_AFU:
> > +               ret = parse_feature_afus(binfo, hdr);
> > +               break;
> > +       case FEATURE_TYPE_PRIVATE:
> > +               ret = parse_feature_private(binfo, hdr);
> > +               break;
> > +       default:
> > +               dev_info(&binfo->pdev->dev,
> > +                        "Feature Type %x is not supported.\n", hdr->type);
> > +       };
> > +
> > +       return ret;
> > +}
> > +
> > +static int
> > +parse_feature_list(struct build_feature_devs_info *binfo, void __iomem *start)
> > +{
> > +       struct feature_header *hdr, header;
> > +       void __iomem *end = binfo->ioend;
> > +       int ret = 0;
> > +
> 
> Maybe a helpful comment that we are stepping through a linked list of features.

Sure, will add more comments.

All kind of features has a common header, they are linked together via the
header.next_header_offset.

If it's a TYPE=AFU feature, it will have one more pointer named NEXT_AFU,
which could point to another TYPE=AFU feature, please refer to function
parse_feature_afus.

If it's a TYPE=private feature, there is no other pointers, please refer
to function parse_feature_private.

> 
> > +       for (; start < end; start += header.next_header_offset) {
> > +               if (end - start < sizeof(*hdr)) {
> > +                       dev_err(&binfo->pdev->dev, "The region is too small to contain a feature.\n");
> > +                       ret =  -EINVAL;
> > +                       break;
> > +               }
> > +
> > +               hdr = (struct feature_header *)start;
> > +               ret = parse_feature(binfo, hdr);
> > +               if (ret)
> > +                       break;
> 
> Instead of parse_feature, this can save off the enumeration info and
> continue to read in the linked list.  After all the headers are read
> in, call the (separate) enumeration code to step through the saved
> headers, parse them, and create the devices.  Since the memory is
> iomapped during the process of reading in the headers, the enumeration
> code doesn't have to be so pcie specific.  Then this code base is
> better set to run on embedded devices also.

Actually, it has parse_feature here, because they're different type of
features. e.g for TYPE = AFU, GUID = PORT, it requires driver to check
its NEXT_AFU pointer to find User AFU (and its header). For private
features, there is no next_afu pointer at all.

> 
> > +
> > +               header.csr = readq(hdr);
> > +               if (!header.next_header_offset)
> > +                       break;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +static int parse_ports_from_fme(struct build_feature_devs_info *binfo)
> > +{
> > +       struct feature_fme_header *fme_hdr;
> > +       struct feature_fme_port port;
> > +       int i = 0, ret = 0;
> > +
> > +       if (binfo->pfme_hdr == NULL) {
> > +               dev_dbg(&binfo->pdev->dev, "VF is detected.\n");
> > +               return ret;
> > +       }
> > +
> > +       fme_hdr = binfo->pfme_hdr;
> > +
> > +       do {
> > +               port.csr = readq(&fme_hdr->port[i]);
> > +               if (!port.port_implemented)
> > +                       break;
> > +
> > +               ret = parse_switch_to(binfo, port.port_bar);
> > +               if (ret)
> > +                       break;
> > +
> > +               ret = parse_feature_list(binfo,
> > +                               binfo->ioaddr + port.port_offset);
> > +               if (ret)
> > +                       break;
> > +       } while (++i < MAX_FPGA_PORT_NUM);
> > +
> > +       return ret;
> > +}
> > +
> > +static int create_init_drvdata(struct pci_dev *pdev)
> > +{
> > +       struct cci_drvdata *drvdata;
> > +
> > +       drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
> > +       if (!drvdata)
> > +               return -ENOMEM;
> > +
> > +       mutex_init(&drvdata->lock);
> > +       INIT_LIST_HEAD(&drvdata->port_dev_list);
> > +       INIT_LIST_HEAD(&drvdata->regions);
> > +
> > +       dev_set_drvdata(&pdev->dev, drvdata);
> > +       return 0;
> > +}
> > +
> > +static void destroy_drvdata(struct pci_dev *pdev)
> > +{
> > +       struct cci_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
> > +
> > +       if (drvdata->fme_dev) {
> > +               /* fme device should be unregistered first. */
> > +               WARN_ON(device_is_registered(drvdata->fme_dev));
> > +               free_fpga_id(FME_ID, to_platform_device(drvdata->fme_dev)->id);
> > +               put_device(drvdata->fme_dev);
> > +       }
> > +
> > +       cci_pci_remove_port_devs(pdev);
> > +       cci_pci_release_regions(pdev);
> > +       dev_set_drvdata(&pdev->dev, NULL);
> > +       devm_kfree(&pdev->dev, drvdata);
> > +}
> > +
> > +static int cci_pci_create_feature_devs(struct pci_dev *pdev)
> > +{
> > +       struct build_feature_devs_info *binfo;
> > +       int ret;
> > +
> > +       binfo = build_info_alloc_and_init(pdev);
> > +       if (!binfo)
> > +               return -ENOMEM;
> > +
> > +       binfo->parent_dev = fpga_dev_create(&pdev->dev, INTEL_FPGA_DEV);
> > +       if (IS_ERR(binfo->parent_dev)) {
> > +               ret = PTR_ERR(binfo->parent_dev);
> > +               goto free_binfo_exit;
> > +       }
> > +
> > +       ret = parse_start(binfo);
> > +       if (ret)
> > +               goto free_binfo_exit;
> > +
> > +       ret = parse_feature_list(binfo, binfo->ioaddr);
> > +       if (ret)
> > +               goto free_binfo_exit;
> > +
> > +       ret = parse_ports_from_fme(binfo);
> > +       if (ret)
> > +               goto free_binfo_exit;
> 
> So ideally, there would be a function call here that read all the
> headers from hardware, ioremapping as it went along.  Then after that,
> call the enumeration code to create the devices.

If we have a function call here which read all the headers, then it
finish most works of parsing the device feature list. The only thing
that enumeration code to do is to create the devices with prepared
resources. It's fine to me, as we can just save information to this
binfo, and create devices later, but is this matches with what you
think? :)

Thanks
Hao

> 
> > +
> > +       ret = build_info_commit_dev(binfo);
> > +       if (ret)
> > +               goto free_binfo_exit;
> > +
> > +       /*
> > +        * everything is okay, reset ->parent_dev to stop it being
> > +        * freed by build_info_free()
> > +        */
> > +       binfo->parent_dev = NULL;
> > +
> > +free_binfo_exit:
> > +       build_info_free(binfo);
> > +       return ret;
> > +}
> > +
> >  /* PCI Device ID */
> >  #define PCIe_DEVICE_ID_PF_INT_5_X      0xBCBD
> >  #define PCIe_DEVICE_ID_PF_INT_6_X      0xBCC0
> > @@ -81,9 +898,18 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
> >                 goto release_region_exit;
> >         }
> >
> > -       /* TODO: create and add the platform device per feature list */
> > +       ret = create_init_drvdata(pcidev);
> > +       if (ret)
> > +               goto release_region_exit;
> > +
> > +       ret = cci_pci_create_feature_devs(pcidev);
> > +       if (ret)
> > +               goto destroy_drvdata_exit;
> > +
> >         return 0;
> >
> > +destroy_drvdata_exit:
> > +       destroy_drvdata(pcidev);
> >  release_region_exit:
> >         pci_release_regions(pcidev);
> >  disable_error_report_exit:
> > @@ -94,6 +920,8 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
> >
> >  static void cci_pci_remove(struct pci_dev *pcidev)
> >  {
> > +       remove_all_devs(pcidev);
> > +       destroy_drvdata(pcidev);
> >         pci_release_regions(pcidev);
> >         pci_disable_pcie_error_reporting(pcidev);
> >         pci_disable_device(pcidev);
> > @@ -108,14 +936,23 @@ static void cci_pci_remove(struct pci_dev *pcidev)
> >
> >  static int __init ccidrv_init(void)
> >  {
> > +       int ret;
> > +
> >         pr_info("Intel(R) FPGA PCIe Driver: Version %s\n", DRV_VERSION);
> >
> > -       return pci_register_driver(&cci_pci_driver);
> > +       fpga_ids_init();
> > +
> > +       ret = pci_register_driver(&cci_pci_driver);
> > +       if (ret)
> > +               fpga_ids_destroy();
> > +
> > +       return ret;
> >  }
> >
> >  static void __exit ccidrv_exit(void)
> >  {
> >         pci_unregister_driver(&cci_pci_driver);
> > +       fpga_ids_destroy();
> >  }
> >
> >  module_init(ccidrv_init);
> > --
> > 1.8.3.1
> >