On Wed, Jul 28, 2021 at 01:54:16PM -0500, Shanker R Donthineni wrote:
> On 7/27/21 5:12 PM, Bjorn Helgaas wrote:
> > On Fri, Jul 09, 2021 at 06:08:06PM +0530, Amey Narkhede wrote:
> >> Add has_pcie_flr bitfield in struct pci_dev to indicate support for PCIe
> >> FLR to avoid reading PCI_EXP_DEVCAP multiple times.
> >>
> >> Currently there is separate function pcie_has_flr() to probe if PCIe FLR
> >> is supported by the device which does not match the calling convention
> >> followed by reset methods which use second function argument to decide
> >> whether to probe or not. Add new function pcie_reset_flr() that follows
> >> the calling convention of reset methods.
> >>
> >> Signed-off-by: Amey Narkhede <ameynarkhede03@xxxxxxxxx>
> >> ---
> >> drivers/crypto/cavium/nitrox/nitrox_main.c | 4 +-
> >> drivers/pci/pci.c | 59 +++++++++++-----------
> >> drivers/pci/pcie/aer.c | 12 ++---
> >> drivers/pci/probe.c | 6 ++-
> >> drivers/pci/quirks.c | 9 ++--
> >> include/linux/pci.h | 3 +-
> >> 6 files changed, 45 insertions(+), 48 deletions(-)
> >>
> >> diff --git a/drivers/crypto/cavium/nitrox/nitrox_main.c b/drivers/crypto/cavium/nitrox/nitrox_main.c
> >> index facc8e6bc..15d6c8452 100644
> >> --- a/drivers/crypto/cavium/nitrox/nitrox_main.c
> >> +++ b/drivers/crypto/cavium/nitrox/nitrox_main.c
> >> @@ -306,9 +306,7 @@ static int nitrox_device_flr(struct pci_dev *pdev)
> >> return -ENOMEM;
> >> }
> >>
> >> - /* check flr support */
> >> - if (pcie_has_flr(pdev))
> >> - pcie_flr(pdev);
> >> + pcie_reset_flr(pdev, 0);
> > I'm not really a fan of exposing the "probe" argument outside
> > drivers/pci/. I think this would be the only occurrence. Is there a
> > way to avoid that?
> >
> > Can we just make pcie_flr() do the equivalent of pcie_has_flr()
> > internally?
> >
> I like your suggestion don't change the existing definition of
> pcie_has_flr()/pcie_flr() and define a new function pcie_reset_flr()
> to fit into the reset framework. This way no need to modify
> logic/drivers outside of driver/pci/xxx.
>
> int pcie_reset_flr(struct pci_dev *dev, int probe)
> {
> if (!pcie_has_flr(dev))
> return -ENOTTY;
>
> if (probe)
> return 0;
>
> return pcie_flr(dev);
> }
Can't remember the whole context of this in the series, but I assume
this would be static?
> And add a new patch to begging of the series for caching 'devcap' in
> pci_dev structure.
>
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -333,6 +333,7 @@ struct pci_dev {
> struct rcec_ea *rcec_ea; /* RCEC cached endpoint association */
> struct pci_dev *rcec; /* Associated RCEC device */
> #endif
> + u32 devcap; /* Cached PCIe device capabilities */
> u8 pcie_cap; /* PCIe capability offset */
> u8 msi_cap; /* MSI capability offset */
> u8 msix_cap; /* MSI-X capability offset */
>
>
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -31,6 +31,7 @@
> #include <linux/vmalloc.h>
> #include <asm/dma.h>
> #include <linux/aer.h>
> +#include <linux/bitfield.h>
> #include "pci.h"
>
> DEFINE_MUTEX(pci_slot_mutex);
> @@ -4630,13 +4631,10 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction);
> */
> bool pcie_has_flr(struct pci_dev *dev)
> {
> - u32 cap;
> -
> if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
> return false;
>
> - pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
> - return cap & PCI_EXP_DEVCAP_FLR;
> + return !!FIELD_GET(PCI_EXP_DEVCAP_FLR, dev->devcap);
Nice, thanks for reminding me of FIELD_GET(). I like how that works
without having to #define *_SHIFT values. I personally don't care for
"!!" and would probably write something like:
return FIELD_GET(PCI_EXP_DEVCAP_FLR, dev->devcap) == 1;
> }
>
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -19,6 +19,7 @@
> #include <linux/hypervisor.h>
> #include <linux/irqdomain.h>
> #include <linux/pm_runtime.h>
> +#include <linux/bitfield.h>
> #include "pci.h"
>
> #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
> @@ -1498,8 +1499,8 @@ void set_pcie_port_type(struct pci_dev *pdev)
> pdev->pcie_cap = pos;
> pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, ®16);
> pdev->pcie_flags_reg = reg16;
> - pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16);
> - pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
> + pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP, &pdev->devcap);
> + pdev->pcie_mpss = FIELD_GET(PCI_EXP_DEVCAP_PAYLOAD, pdev->devcap);
>
