Ping !
Regards,
Parshuram Thombare
>-----Original Message-----
>From: Parshuram Raju Thombare <pthombar@xxxxxxxxxxx>
>Sent: Tuesday, November 16, 2021 1:09 PM
>To: bhelgaas@xxxxxxxxxx; kishon@xxxxxx; Tom Joseph
><tjoseph@xxxxxxxxxxx>; lorenzo.pieralisi@xxxxxxx; robh@xxxxxxxxxx;
>kw@xxxxxxxxx
>Cc: linux-omap@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-arm-
>kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Milind Parab
><mparab@xxxxxxxxxxx>; Parshuram Raju Thombare
><pthombar@xxxxxxxxxxx>
>Subject: [PATCH v2] PCI: cadence: Clear FLR in device capabilities register
>
>From: Parshuram Thombare <pthombar@xxxxxxxxxxx>
>
>Clear FLR (Function Level Reset) from device capabilities
>registers for all physical functions.
>
>During FLR, the Margining Lane Status and Margining Lane Control
>registers should not be reset, as per PCIe specification.
>However, the controller incorrectly resets these registers upon FLR.
>This causes PCISIG compliance FLR test to fail. Hence preventing
>all functions from advertising FLR support if flag quirk_disable_flr
>is set.
>
>Signed-off-by: Parshuram Thombare <pthombar@xxxxxxxxxxx>
>---
>Changes since v1:
>Changes suggested by Bjorn in the description.
>
>---
> drivers/pci/controller/cadence/pci-j721e.c | 3 +++
> drivers/pci/controller/cadence/pcie-cadence-ep.c | 18 +++++++++++++++++-
> drivers/pci/controller/cadence/pcie-cadence.h | 3 +++
> 3 files changed, 23 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/pci/controller/cadence/pci-j721e.c
>b/drivers/pci/controller/cadence/pci-j721e.c
>index ffb176d..635e36c 100644
>--- a/drivers/pci/controller/cadence/pci-j721e.c
>+++ b/drivers/pci/controller/cadence/pci-j721e.c
>@@ -70,6 +70,7 @@ struct j721e_pcie_data {
> enum j721e_pcie_mode mode;
> unsigned int quirk_retrain_flag:1;
> unsigned int quirk_detect_quiet_flag:1;
>+ unsigned int quirk_disable_flr:1;
> u32 linkdown_irq_regfield;
> unsigned int byte_access_allowed:1;
> };
>@@ -308,6 +309,7 @@ static int cdns_ti_pcie_config_write(struct pci_bus *bus,
>unsigned int devfn,
> static const struct j721e_pcie_data j7200_pcie_ep_data = {
> .mode = PCI_MODE_EP,
> .quirk_detect_quiet_flag = true,
>+ .quirk_disable_flr = true,
> };
>
> static const struct j721e_pcie_data am64_pcie_rc_data = {
>@@ -510,6 +512,7 @@ static int j721e_pcie_probe(struct platform_device
>*pdev)
> goto err_get_sync;
> }
> ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;
>+ ep->quirk_disable_flr = data->quirk_disable_flr;
>
> cdns_pcie = &ep->pcie;
> cdns_pcie->dev = dev;
>diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c
>b/drivers/pci/controller/cadence/pcie-cadence-ep.c
>index 88e05b9..4b1c4bc 100644
>--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
>+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
>@@ -565,7 +565,8 @@ static int cdns_pcie_ep_start(struct pci_epc *epc)
> struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
> struct cdns_pcie *pcie = &ep->pcie;
> struct device *dev = pcie->dev;
>- int ret;
>+ int max_epfs = sizeof(epc->function_num_map) * 8;
>+ int ret, value, epf;
>
> /*
> * BIT(0) is hardwired to 1, hence function 0 is always enabled
>@@ -573,6 +574,21 @@ static int cdns_pcie_ep_start(struct pci_epc *epc)
> */
> cdns_pcie_writel(pcie, CDNS_PCIE_LM_EP_FUNC_CFG, epc-
>>function_num_map);
>
>+ if (ep->quirk_disable_flr) {
>+ for (epf = 0; epf < max_epfs; epf++) {
>+ if (!(epc->function_num_map & BIT(epf)))
>+ continue;
>+
>+ value = cdns_pcie_ep_fn_readl(pcie, epf,
>+
> CDNS_PCIE_EP_FUNC_DEV_CAP_OFFSET +
>+ PCI_EXP_DEVCAP);
>+ value &= ~PCI_EXP_DEVCAP_FLR;
>+ cdns_pcie_ep_fn_writel(pcie, epf,
>+
> CDNS_PCIE_EP_FUNC_DEV_CAP_OFFSET +
>+ PCI_EXP_DEVCAP, value);
>+ }
>+ }
>+
> ret = cdns_pcie_start_link(pcie);
> if (ret) {
> dev_err(dev, "Failed to start link\n");
>diff --git a/drivers/pci/controller/cadence/pcie-cadence.h
>b/drivers/pci/controller/cadence/pcie-cadence.h
>index 262421e..e978e7c 100644
>--- a/drivers/pci/controller/cadence/pcie-cadence.h
>+++ b/drivers/pci/controller/cadence/pcie-cadence.h
>@@ -123,6 +123,7 @@
>
> #define CDNS_PCIE_EP_FUNC_MSI_CAP_OFFSET 0x90
> #define CDNS_PCIE_EP_FUNC_MSIX_CAP_OFFSET 0xb0
>+#define CDNS_PCIE_EP_FUNC_DEV_CAP_OFFSET 0xc0
> #define CDNS_PCIE_EP_FUNC_SRIOV_CAP_OFFSET 0x200
>
> /*
>@@ -357,6 +358,7 @@ struct cdns_pcie_epf {
> * minimize time between read and write
> * @epf: Structure to hold info about endpoint function
> * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk
>+ * @quirk_disable_flr: Disable FLR (Function Level Reset) quirk flag
> */
> struct cdns_pcie_ep {
> struct cdns_pcie pcie;
>@@ -372,6 +374,7 @@ struct cdns_pcie_ep {
> spinlock_t lock;
> struct cdns_pcie_epf *epf;
> unsigned int quirk_detect_quiet_flag:1;
>+ unsigned int quirk_disable_flr:1;
> };
>
>
>--
>1.9.1
