RE: [PATCH v3 04/11] PCI: designware-ep: Modify MSI and MSIX CAP way of finding

From: Xiaowei Bao
Date: Mon Sep 02 2019 - 22:33:34 EST

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> -----Original Message-----
> From: Andrew Murray <andrew.murray@xxxxxxx>
> Sent: 2019年9月2日 23:07
> To: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> Cc: robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; shawnguo@xxxxxxxxxx; Leo
> Li <leoyang.li@xxxxxxx>; kishon@xxxxxx; lorenzo.pieralisi@xxxxxxx; M.h.
> Lian <minghuan.lian@xxxxxxx>; Mingkai Hu <mingkai.hu@xxxxxxx>; Roy
> Zang <roy.zang@xxxxxxx>; jingoohan1@xxxxxxxxx;
> gustavo.pimentel@xxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx;
> arnd@xxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Z.q. Hou
> <zhiqiang.hou@xxxxxxx>
> Subject: Re: [PATCH v3 04/11] PCI: designware-ep: Modify MSI and MSIX CAP
> way of finding
>
> On Mon, Sep 02, 2019 at 11:17:09AM +0800, Xiaowei Bao wrote:
> > Each PF of EP device should have it's own MSI or MSIX capabitily
> > struct, so create a dw_pcie_ep_func struct and remover the msi_cap
>
> remover?

Sorry. ^_^

>
> > and msix_cap to this struce, and manage the PFs with a list.
>
> struce?
>
> >
> > Signed-off-by: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > ---
> > v1:
> > - This is a new patch, to fix the issue of MSI and MSIX CAP way of
> > finding.
> > v2:
> > - No change.
> > v3:
> > - No change.
>
> This makes it look like you introduced the patch in v1 and haven't changed it
> since.
>
> I think it's more common to have a history like this:
>
> ---
> v3:
> - Introduced new patch, to fix the issue of MSI and MSIX CAP way of
> finding.

OK, thanks, I am not clear the rules, thanks a lot for your help.

Thanks
Xiaowei

>
>
> >
> > drivers/pci/controller/dwc/pcie-designware-ep.c | 135
> +++++++++++++++++++++---
> > drivers/pci/controller/dwc/pcie-designware.h | 18 +++-
> > 2 files changed, 134 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > index c3bc7bd..144eb12 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > @@ -19,6 +19,19 @@ void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
> > pci_epc_linkup(epc);
> > }
> >
> > +struct dw_pcie_ep_func *
> > +dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no) {
> > + struct dw_pcie_ep_func *ep_func;
> > +
> > + list_for_each_entry(ep_func, &ep->func_list, list) {
> > + if (ep_func->func_no == func_no)
> > + return ep_func;
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > static unsigned int dw_pcie_ep_func_select(struct dw_pcie_ep *ep, u8
> > func_no) {
> > unsigned int func_offset = 0;
> > @@ -59,6 +72,47 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci,
> enum pci_barno bar)
> > __dw_pcie_ep_reset_bar(pci, func_no, bar, 0); }
> >
> > +static u8 __dw_pcie_ep_find_next_cap(struct dw_pcie_ep *ep, u8
> func_no,
> > + u8 cap_ptr, u8 cap)
> > +{
> > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + unsigned int func_offset = 0;
> > + u8 cap_id, next_cap_ptr;
> > + u16 reg;
> > +
> > + if (!cap_ptr)
> > + return 0;
> > +
> > + func_offset = dw_pcie_ep_func_select(ep, func_no);
> > +
> > + reg = dw_pcie_readw_dbi(pci, func_offset + cap_ptr);
> > + cap_id = (reg & 0x00ff);
> > +
> > + if (cap_id > PCI_CAP_ID_MAX)
> > + return 0;
> > +
> > + if (cap_id == cap)
> > + return cap_ptr;
> > +
> > + next_cap_ptr = (reg & 0xff00) >> 8;
> > + return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap); }
>
> Which tree have you based this patchset on? v5.3-rc3 and pci/dwc both
> already have this function (without the func_no). See beb4641a787d
> ("PCI: dwc: Add MSI-X callbacks handler").

There is a commit 7a6854f68 in the latest kernel.

Thanks
Xiaowei

>
> > +
> > +static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8
> > +func_no, u8 cap) {
> > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + unsigned int func_offset = 0;
> > + u8 next_cap_ptr;
> > + u16 reg;
> > +
> > + func_offset = dw_pcie_ep_func_select(ep, func_no);
> > +
> > + reg = dw_pcie_readw_dbi(pci, func_offset + PCI_CAPABILITY_LIST);
> > + next_cap_ptr = (reg & 0x00ff);
> > +
> > + return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap); }
> > +
> > static int dw_pcie_ep_write_header(struct pci_epc *epc, u8 func_no,
> > struct pci_epf_header *hdr)
> > {
> > @@ -246,13 +300,18 @@ static int dw_pcie_ep_get_msi(struct pci_epc
> *epc, u8 func_no)
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > u32 val, reg;
> > unsigned int func_offset = 0;
> > + struct dw_pcie_ep_func *ep_func;
> >
> > - if (!ep->msi_cap)
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> > +
> > + if (!ep_func->msi_cap)
> > return -EINVAL;
> >
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > - reg = ep->msi_cap + func_offset + PCI_MSI_FLAGS;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_FLAGS;
> > val = dw_pcie_readw_dbi(pci, reg);
> > if (!(val & PCI_MSI_FLAGS_ENABLE))
> > return -EINVAL;
> > @@ -268,13 +327,18 @@ static int dw_pcie_ep_set_msi(struct pci_epc
> *epc, u8 func_no, u8 interrupts)
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > u32 val, reg;
> > unsigned int func_offset = 0;
> > + struct dw_pcie_ep_func *ep_func;
> > +
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> >
> > - if (!ep->msi_cap)
> > + if (!ep_func->msi_cap)
> > return -EINVAL;
> >
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > - reg = ep->msi_cap + func_offset + PCI_MSI_FLAGS;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_FLAGS;
> > val = dw_pcie_readw_dbi(pci, reg);
> > val &= ~PCI_MSI_FLAGS_QMASK;
> > val |= (interrupts << 1) & PCI_MSI_FLAGS_QMASK; @@ -291,13 +355,18
> > @@ static int dw_pcie_ep_get_msix(struct pci_epc *epc, u8 func_no)
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > u32 val, reg;
> > unsigned int func_offset = 0;
> > + struct dw_pcie_ep_func *ep_func;
> > +
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> >
> > - if (!ep->msix_cap)
> > + if (!ep_func->msix_cap)
> > return -EINVAL;
> >
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > - reg = ep->msix_cap + func_offset + PCI_MSIX_FLAGS;
> > + reg = ep_func->msix_cap + func_offset + PCI_MSIX_FLAGS;
> > val = dw_pcie_readw_dbi(pci, reg);
> > if (!(val & PCI_MSIX_FLAGS_ENABLE))
> > return -EINVAL;
> > @@ -313,13 +382,18 @@ static int dw_pcie_ep_set_msix(struct pci_epc
> *epc, u8 func_no, u16 interrupts)
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > u32 val, reg;
> > unsigned int func_offset = 0;
> > + struct dw_pcie_ep_func *ep_func;
> >
> > - if (!ep->msix_cap)
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> > +
> > + if (!ep_func->msix_cap)
> > return -EINVAL;
> >
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > - reg = ep->msix_cap + func_offset + PCI_MSIX_FLAGS;
> > + reg = ep_func->msix_cap + func_offset + PCI_MSIX_FLAGS;
> > val = dw_pcie_readw_dbi(pci, reg);
> > val &= ~PCI_MSIX_FLAGS_QSIZE;
> > val |= interrupts;
> > @@ -404,6 +478,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep
> *ep, u8 func_no,
> > u8 interrupt_num)
> > {
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + struct dw_pcie_ep_func *ep_func;
> > struct pci_epc *epc = ep->epc;
> > unsigned int aligned_offset;
> > unsigned int func_offset = 0;
> > @@ -413,25 +488,29 @@ int dw_pcie_ep_raise_msi_irq(struct
> dw_pcie_ep *ep, u8 func_no,
> > bool has_upper;
> > int ret;
> >
> > - if (!ep->msi_cap)
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> > +
> > + if (!ep_func->msi_cap)
> > return -EINVAL;
> >
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > /* Raise MSI per the PCI Local Bus Specification Revision 3.0, 6.8.1. */
> > - reg = ep->msi_cap + func_offset + PCI_MSI_FLAGS;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_FLAGS;
> > msg_ctrl = dw_pcie_readw_dbi(pci, reg);
> > has_upper = !!(msg_ctrl & PCI_MSI_FLAGS_64BIT);
> > - reg = ep->msi_cap + func_offset + PCI_MSI_ADDRESS_LO;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_ADDRESS_LO;
> > msg_addr_lower = dw_pcie_readl_dbi(pci, reg);
> > if (has_upper) {
> > - reg = ep->msi_cap + func_offset + PCI_MSI_ADDRESS_HI;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_ADDRESS_HI;
> > msg_addr_upper = dw_pcie_readl_dbi(pci, reg);
> > - reg = ep->msi_cap + func_offset + PCI_MSI_DATA_64;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_DATA_64;
> > msg_data = dw_pcie_readw_dbi(pci, reg);
> > } else {
> > msg_addr_upper = 0;
> > - reg = ep->msi_cap + func_offset + PCI_MSI_DATA_32;
> > + reg = ep_func->msi_cap + func_offset + PCI_MSI_DATA_32;
> > msg_data = dw_pcie_readw_dbi(pci, reg);
> > }
> > aligned_offset = msg_addr_lower & (epc->mem->page_size - 1); @@
> > -467,6 +546,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep,
> u8 func_no,
> > u16 interrupt_num)
> > {
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + struct dw_pcie_ep_func *ep_func;
> > struct pci_epc *epc = ep->epc;
> > u16 tbl_offset, bir;
> > unsigned int func_offset = 0;
> > @@ -477,9 +557,16 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep
> *ep, u8 func_no,
> > void __iomem *msix_tbl;
> > int ret;
> >
> > + ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > + if (!ep_func)
> > + return -EINVAL;
> > +
> > + if (!ep_func->msix_cap)
> > + return -EINVAL;
> > +
> > func_offset = dw_pcie_ep_func_select(ep, func_no);
> >
> > - reg = ep->msix_cap + func_offset + PCI_MSIX_TABLE;
> > + reg = ep_func->msix_cap + func_offset + PCI_MSIX_TABLE;
> > tbl_offset = dw_pcie_readl_dbi(pci, reg);
> > bir = (tbl_offset & PCI_MSIX_TABLE_BIR);
> > tbl_offset &= PCI_MSIX_TABLE_OFFSET; @@ -558,6 +645,7 @@ int
> > dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > int i;
> > int ret;
> > u32 reg;
> > + u8 func_no;
> > void *addr;
> > unsigned int nbars;
> > unsigned int offset;
> > @@ -565,6 +653,9 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > struct device *dev = pci->dev;
> > struct device_node *np = dev->of_node;
> > + struct dw_pcie_ep_func *ep_func;
> > +
> > + INIT_LIST_HEAD(&ep->func_list);
> >
> > if (!pci->dbi_base || !pci->dbi_base2) {
> > dev_err(dev, "dbi_base/dbi_base2 is not populated\n"); @@ -624,9
> > +715,19 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > if (ret < 0)
> > epc->max_functions = 1;
> >
> > - ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
> > + for (func_no = 0; func_no < epc->max_functions; func_no++) {
> > + ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
> > + if (!ep_func)
> > + return -ENOMEM;
> >
> > - ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
> > + ep_func->func_no = func_no;
> > + ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
> > + PCI_CAP_ID_MSI);
> > + ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
> > + PCI_CAP_ID_MSIX);
> > +
> > + list_add_tail(&ep_func->list, &ep->func_list);
> > + }
>
> Whilst your patch addresses the issue of giving each function the ability to
> have differing capabilities - I feel that this solution doesn't go deep enough.
>
> In my view the root issue here is that 'struct dw_pcie_ep' represents both a
> EP controller and a *single* EP function. I think that there should be a
> representation for an EP controller and a representation for a EP function (i.e.
> some separation). Thus allowing one EP controller to have many EP functions.
> This isn't too dissimilar to host bridges and their functions.
> Others here may have different views.
>
> It may be unlikely now, but EP functions belonging to the same bit of IP may
> have differing functionality - your approach addresses that for MSI/MSI
> capabilities, but what about other differences?

Sorry, I am not clear about the other differences is? are there have any defect?

>
> (It would be really nice as well if an EP controller could provide config
> read/write ops such that existing functions in the core such as
> __pci_find_next_capability could be reused - instead of copying them like
> dw_pcie_ep_find_capability. However I don't think this is feasible.)

Yes, agree you viewpoint, but this is the best way that I can thought ^_^,
may be others can give the best solution.

Thanks
Xiaowei

>
> Thanks,
>
> Andrew Murray
>
> >
> > if (ep->ops->ep_init)
> > ep->ops->ep_init(ep);
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h
> > b/drivers/pci/controller/dwc/pcie-designware.h
> > index 56789be..a57743c 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -221,8 +221,16 @@ struct dw_pcie_ep_ops {
> > unsigned int (*func_conf_select)(struct dw_pcie_ep *ep, u8 func_no);
> > };
> >
> > +struct dw_pcie_ep_func {
> > + struct list_head list;
> > + u8 func_no;
> > + u8 msi_cap; /* MSI capability offset */
> > + u8 msix_cap; /* MSI-X capability offset */
> > +};
> > +
> > struct dw_pcie_ep {
> > struct pci_epc *epc;
> > + struct list_head func_list;
> > const struct dw_pcie_ep_ops *ops;
> > phys_addr_t phys_base;
> > size_t addr_size;
> > @@ -235,8 +243,6 @@ struct dw_pcie_ep {
> > u32 num_ob_windows;
> > void __iomem *msi_mem;
> > phys_addr_t msi_mem_phys;
> > - u8 msi_cap; /* MSI capability offset */
> > - u8 msix_cap; /* MSI-X capability offset */
> > };
> >
> > struct dw_pcie_ops {
> > @@ -425,6 +431,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep
> > *ep, u8 func_no, int dw_pcie_ep_raise_msix_irq_doorbell(struct
> dw_pcie_ep *ep, u8 func_no,
> > u16 interrupt_num);
> > void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar);
> > +struct dw_pcie_ep_func *
> > +dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no);
> > #else
> > static inline void dw_pcie_ep_linkup(struct dw_pcie_ep *ep) { @@
> > -466,5 +474,11 @@ static inline int
> > dw_pcie_ep_raise_msix_irq_doorbell(struct dw_pcie_ep *ep, static
> > inline void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno
> > bar) { }
> > +
> > +struct dw_pcie_ep_func *
> > +dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no) {
> > + return NULL;
> > +}
> > #endif
> > #endif /* _PCIE_DESIGNWARE_H */
> > --
> > 2.9.5
> >

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