Re: [PATCH v8 6/8] PCI: cadence: Add support to configure virtual functions

Kishon Vijay Abraham I
2021-08-18T13:56:04Z

Hi Bjorn,

On 17/08/21 9:08 pm, Bjorn Helgaas wrote:
> On Wed, Aug 11, 2021 at 12:16:54PM +0530, Kishon Vijay Abraham I wrote:
>> Now that support for SR-IOV is added in PCIe endpoint core, add support
>> to configure virtual functions in the Cadence PCIe EP driver.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>> ---
>> .../pci/controller/cadence/pcie-cadence-ep.c | 136 +++++++++++++++---
>> drivers/pci/controller/cadence/pcie-cadence.h | 9 ++
>> 2 files changed, 125 insertions(+), 20 deletions(-)
>
>> @@ -92,21 +118,29 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, u8 vfn,
>>
>> addr0 = lower_32_bits(bar_phys);
>> addr1 = upper_32_bits(bar_phys);
>> - cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar),
>> - addr0);
>> - cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar),
>> - addr1);
>>
>> reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn);
>> + if (vfn == 1)
>> + reg = CDNS_PCIE_LM_EP_VFUNC_BAR_CFG(bar, fn);
>
> Seems sort of weird to compute "reg", then sometimes overwrite it, as
> opposed to:
>
> if (vfn == 1)
> reg = CDNS_PCIE_LM_EP_VFUNC_BAR_CFG(bar, fn);
> else
> reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn);

I tried to write it without "else". But I can change it back.
>
> Also slightly weird that "vfn" is basically used as a boolean, but
> it's actually a u8 virtual function number. I guess VF 1 is special
> and not like the other VFs?

VF1 is special in that it's enough for configuring the SR-IOV capability
but below the "vfn" is used for configuring inbound window.

Thanks
Kishon
>
>> b = (bar < BAR_4) ? bar : bar - BAR_4;
>>
>> - cfg = cdns_pcie_readl(pcie, reg);
>> - cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
>> - CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b));
>> - cfg |= (CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, aperture) |
>> - CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl));
>> - cdns_pcie_writel(pcie, reg, cfg);
>> + if (vfn == 0 || vfn == 1) {
>> + cfg = cdns_pcie_readl(pcie, reg);
>> + cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
>> + CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b));
>> + cfg |= (CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, aperture) |
>> + CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl));
>> + cdns_pcie_writel(pcie, reg, cfg);
>> + }
>>
>> + fn = cdns_pcie_get_fn_from_vfn(pcie, fn, vfn);
>> + cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar),
>> + addr0);
>> + cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar),
>> + addr1);
>> +
>> + if (vfn > 0)
>> + epf = &epf->epf[vfn - 1];
>> epf->epf_bar[bar] = epf_bar;
>>
>> return 0;
>> @@ -122,18 +156,25 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn, u8 vfn,
>> u32 reg, cfg, b, ctrl;
>>
>> reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG(bar, fn);
>> + if (vfn == 1)
>> + reg = CDNS_PCIE_LM_EP_VFUNC_BAR_CFG(bar, fn);
>
> Similar recomputation of "reg".
>
>> b = (bar < BAR_4) ? bar : bar - BAR_4;
>>
>> - ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>> - cfg = cdns_pcie_readl(pcie, reg);
>> - cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
>> - CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b));
>> - cfg |= CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl);
>> - cdns_pcie_writel(pcie, reg, cfg);
>> + if (vfn == 0 || vfn == 1) {
>> + ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>> + cfg = cdns_pcie_readl(pcie, reg);
>> + cfg &= ~(CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) |
>> + CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b));
>> + cfg |= CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl);
>> + cdns_pcie_writel(pcie, reg, cfg);
>> + }