Re: [PATCH V8 2/2] scsi: ufs: Add configfs support for UFS provisioning

[Sayali Lokhande]

On 8/17/2018 11:47 PM, Evan Green wrote:
> On Thu, Aug 9, 2018 at 2:10 AM Sayali Lokhande <sayalil@xxxxxxxxxxxxxx> wrote:
> > This patch adds configfs support to provision UFS device at
> > runtime. This feature can be primarily useful in factory or
> > assembly line as some devices may be required to be configured
> > multiple times during initial system development phase.
> > Configuration Descriptors can be written multiple times until
> > bConfigDescrLock attribute is zero.
> >
> > Configuration descriptor buffer consists of Device and Unit
> > descriptor configurable parameters which are parsed from vendor
> > specific provisioning file and then passed via configfs node at
> > runtime to provision ufs device.
> > CONFIG_CONFIGFS_FS needs to be enabled for using this feature.
> >
> > Usage:
> > 1) To read current configuration descriptor :
> >     cat /config/XXXX.ufshc/ufs_provision
> > 2) To provision ufs device:
> >     echo <config_desc_buf> > /config/XXXX.ufshc/ufs_provision
> >
> > Signed-off-by: Sayali Lokhande <sayalil@xxxxxxxxxxxxxx>
> > ---
> >   Documentation/ABI/testing/configfs-driver-ufs |  18 +++
> >   drivers/scsi/ufs/Kconfig                      |  10 ++
> >   drivers/scsi/ufs/Makefile                     |   1 +
> >   drivers/scsi/ufs/ufs-configfs.c               | 159 ++++++++++++++++++++++++++
> >   drivers/scsi/ufs/ufshcd.c                     |   7 +-
> >   drivers/scsi/ufs/ufshcd.h                     |  10 ++
> >   6 files changed, 204 insertions(+), 1 deletion(-)
> >   create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
> >   create mode 100644 drivers/scsi/ufs/ufs-configfs.c
> >
> > diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs
> > new file mode 100644
> > index 0000000..eeee499c
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/configfs-driver-ufs
> > @@ -0,0 +1,18 @@
> > +What:          /config/ufshcd/ufs_provision
> > +Date:          Jun 2018
> > +KernelVersion: 4.14
> > +Description:
> > +               This file shows the current ufs configuration descriptor set in device.
> > +               This can be used to provision ufs device if bConfigDescrLock is 0.
> > +               For more details, refer 14.1.6.3 Configuration Descriptor and
> > +               Table 14-12 - Unit Descriptor configurable parameters from specs for
> > +               description of each configuration descriptor parameter.
> > +               Configuration descriptor buffer needs to be passed in space separated
> > +               format specificied as below:
> > +               echo <bLength> <bDescriptorIDN> <bConfDescContinue> <bBootEnable>
> > +               <bDescrAccessEn> <bInitPowerMode> <bHighPriorityLUN>
> > +               <bSecureRemovalType> <bInitActiveICCLevel> <wPeriodicRTCUpdate>
> > +               <0Bh:0Fh_ReservedAs_0> <bLUEnable> <bBootLunID> <bLUWriteProtect>
> > +               <bMemoryType> <dNumAllocUnits> <bDataReliability> <bLogicalBlockSize>
> > +               <bProvisioningType> <wContextCapabilities> <0Dh:0Fh_ReservedAs_0>
> > +               > /config/XXXX.ufshc/ufs_provision
> > diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> > index e27b4d4..a9a0a58 100644
> > --- a/drivers/scsi/ufs/Kconfig
> > +++ b/drivers/scsi/ufs/Kconfig
> > @@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
> >
> >            Select this if you have UFS controller on QCOM chipset.
> >            If unsure, say N.
> > +
> > +config UFS_PROVISION
> > +       tristate "Runtime UFS Provisioning support"
> > +       depends on SCSI_UFSHCD && CONFIGFS_FS
> > +       help
> > +         This enables runtime UFS provisioning support. This can be used
> > +         primarily during assembly line as some devices may be required to
> > +         be configured multiple times during initial development phase.
> > +
> > +         If unsure, say N.
> > diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
> > index 918f579..00110ea 100644
> > --- a/drivers/scsi/ufs/Makefile
> > +++ b/drivers/scsi/ufs/Makefile
> > @@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
> >   obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
> >   obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
> >   ufshcd-core-objs := ufshcd.o ufs-sysfs.o
> > +obj-$(CONFIG_UFS_PROVISION) += ufs-configfs.o
> >   obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
> >   obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
> > diff --git a/drivers/scsi/ufs/ufs-configfs.c b/drivers/scsi/ufs/ufs-configfs.c
> > new file mode 100644
> > index 0000000..cd1a227
> > --- /dev/null
> > +++ b/drivers/scsi/ufs/ufs-configfs.c
> > @@ -0,0 +1,159 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +// Copyright (c) 2018, Linux Foundation.
> > +
> > +#include <linux/configfs.h>
> > +#include <linux/err.h>
> > +#include <linux/string.h>
> > +
> > +#include "ufs.h"
> > +#include "ufshcd.h"
> > +
> > +static inline struct ufs_hba *config_item_to_hba(struct config_item *item)
> > +{
> > +       struct config_group *group = to_config_group(item);
> > +       struct configfs_subsystem *subsys = to_configfs_subsystem(group);
> > +       struct ufs_hba *hba = container_of(subsys, struct ufs_hba, subsys);
> > +
> > +       return subsys ? hba : NULL;
> > +}
> > +
> > +static ssize_t ufs_provision_show(struct config_item *item, char *buf)
> > +{
> > +       u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
> > +       int buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
> > +       int i, ret, curr_len = 0;
> > +       struct ufs_hba *hba = config_item_to_hba(item);
> > +
> > +       if (!hba)
> > +               return -EINVAL;
> I don't think this is actually possible. Is a configfs show function
> ever called with a null item?
Agree. In init , we get the valid hba pointer. So I can remove this 
check. Will update.
> > +
> > +       ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
> > +               QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &buff_len);
> > +
> > +       if (ret)
> > +               return ret;
> > +
> > +       for (i = 0; i < buff_len; i++)
> > +               curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
> > +                               "0x%x ", desc_buf[i]);
> > +
> > +       return curr_len;
> > +}
> > +
> > +ssize_t ufshcd_desc_configfs_store(struct ufs_hba *hba,
> > +               const char *buf, size_t count)
> > +{
> > +       char *strbuf;
> > +       char *strbuf_copy;
> > +       u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
> > +       int buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
> > +       char *token;
> > +       int i, ret, value;
> > +       u32 bConfigDescrLock = 0;
> I haven't seen many examples of variables named this way. I know it
> follows what the UFS spec does, but I haven't noticed examples of
> people naming their locals outside of normal Linux conventions.
Done. Will update the naming.
> > +
> > +       /* reserve one byte for null termination */
> > +       strbuf = kmalloc(count + 1, GFP_KERNEL);
> > +       if (!strbuf)
> > +               return -ENOMEM;
> > +
> > +       strbuf_copy = strbuf;
> > +       strlcpy(strbuf, buf, count + 1);
> > +
> > +       if (!hba)
> > +               goto out;
> Again, is this possible?
Done. will remove this check.
> > +
> > +       /* Just return if bConfigDescrLock is already set */
> > +       ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> > +               QUERY_ATTR_IDN_CONF_DESC_LOCK, 0, 0, &bConfigDescrLock);
> > +       if (ret)
> > +               goto out;
> > +
> > +       if (bConfigDescrLock) {
> > +               dev_err(hba->dev, "%s: bConfigDescrLock already set to %u, cannot re-provision device!\n",
> > +               __func__, bConfigDescrLock);
> > +               goto out;
> You're succeeding here, shouldn't you fail the write? In fact, you
> succeed the write in a whole bunch of failure cases. Please fail the
> write in error cases.
Agree. Will set the err val in return and check for error/ret set and 
return accordingly.
> > +       }
> > +
> > +       for (i = 0; i < QUERY_DESC_CONFIGURATION_DEF_SIZE; i++) {
> > +               token = strsep(&strbuf, " ");
> > +               if (!token && i)
> > +                       break;
> > +
> > +               ret = kstrtoint(token, 0, &value);
> > +               if (ret) {
> > +                       dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
> > +                               __func__, ret, token);
> > +                       goto out;
> > +               }
> > +               desc_buf[i] = (u8)value;
> > +       }
> > +
> > +       /* Write configuration descriptor to provision ufs */
> > +       ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_WRITE_DESC,
> > +               QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &buff_len);
> > +
> > +       if (!ret)
> > +               dev_err(hba->dev, "%s: UFS Provisioning done, reboot now!\n",
> > +               __func__);
> > +
> > +out:
> > +       kfree(strbuf_copy);
> > +       return count;
> > +}
> > +
> > +static ssize_t ufs_provision_store(struct config_item *item,
> > +               const char *buf, size_t count)
> > +{
> > +       struct ufs_hba *hba = config_item_to_hba(item);
> > +
> > +       return ufshcd_desc_configfs_store(hba, buf, count);
> > +}
> > +
> > +static struct configfs_attribute ufshcd_attr_provision = {
> > +       .ca_name        = "ufs_provision",
> > +       .ca_mode        = 0644,
> > +       .ca_owner       = THIS_MODULE,
> > +       .show           = ufs_provision_show,
> > +       .store          = ufs_provision_store,
> > +};
> > +
> > +static struct configfs_attribute *ufshcd_attrs[] = {
> > +       &ufshcd_attr_provision,
> > +       NULL,
> > +};
> > +
> > +static struct config_item_type ufscfg_type = {
> > +       .ct_attrs       = ufshcd_attrs,
> > +       .ct_owner       = THIS_MODULE,
> > +};
> > +
> > +static struct configfs_subsystem ufscfg_subsys = {
> > +       .su_group = {
> > +               .cg_item = {
> > +                       .ci_type = &ufscfg_type,
> > +               },
> > +       },
> > +};
> > +
> > +int ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
> > +{
> > +       int ret;
> > +       struct configfs_subsystem *subsys = &hba->subsys;
> > +
> > +       strncpy(ufscfg_subsys.su_group.cg_item.ci_namebuf, name, strlen(name));
> > +       subsys->su_group = ufscfg_subsys.su_group;
> > +       config_group_init(&subsys->su_group);
> > +       mutex_init(&subsys->su_mutex);
> > +       ret = configfs_register_subsystem(subsys);
> > +       if (ret)
> > +               pr_err("Error %d while registering subsystem %s\n",
> > +                      ret,
> > +                      subsys->su_group.cg_item.ci_namebuf);
> > +
> > +       return ret;
> > +}
> > +
> > +void ufshcd_configfs_exit(void)
> > +{
> > +       configfs_unregister_subsystem(&ufscfg_subsys);
> > +}
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 0cbdde7..bc7bffc 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -7711,6 +7711,9 @@ int ufshcd_shutdown(struct ufs_hba *hba)
> >   void ufshcd_remove(struct ufs_hba *hba)
> >   {
> >          ufs_sysfs_remove_nodes(hba->dev);
> > +#ifdef CONFIG_UFS_PROVISION
> > +       ufshcd_configfs_exit();
> > +#endif
> >          scsi_remove_host(hba->host);
> >          /* disable interrupts */
> >          ufshcd_disable_intr(hba, hba->intr_mask);
> > @@ -7964,7 +7967,9 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
> >
> >          async_schedule(ufshcd_async_scan, hba);
> >          ufs_sysfs_add_nodes(hba->dev);
> > -
> > +#ifdef CONFIG_UFS_PROVISION
> > +       ufshcd_configfs_init(hba, dev_name(hba->dev));
> > +#endif
> Normally the way I see this done is to define stub functions up in the
> header when !CONFIG_UFS_PROVISION, rather than ifdefs in the code. Can
> you do it that way?
Done. Will update.
> >          return 0;
> >
> >   out_remove_scsi_host:
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index 101a75c..7b6cc88 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -37,6 +37,7 @@
> >   #ifndef _UFSHCD_H
> >   #define _UFSHCD_H
> >
> > +#include <linux/configfs.h>
> >   #include <linux/module.h>
> >   #include <linux/kernel.h>
> >   #include <linux/init.h>
> > @@ -515,6 +516,9 @@ struct ufs_hba {
> >
> >          struct Scsi_Host *host;
> >          struct device *dev;
> > +#ifdef CONFIG_UFS_PROVISION
> > +       struct configfs_subsystem subsys;
> > +#endif
> >          /*
> >           * This field is to keep a reference to "scsi_device" corresponding to
> >           * "UFS device" W-LU.
> > @@ -868,6 +872,12 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
> >   int ufshcd_hold(struct ufs_hba *hba, bool async);
> >   void ufshcd_release(struct ufs_hba *hba);
> >
> > +/* Expose UFS configfs API's */
> > +#ifdef CONFIG_UFS_PROVISION
> > +extern int ufshcd_configfs_init(struct ufs_hba *hba, const char *name);
> > +extern void ufshcd_configfs_exit(void);
> > +#endif
> > +
> >   int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
> >          int *desc_length);
> >
> > --
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project