| Message ID | 1708697021-16877-3-git-send-email-quic_msarkar@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: qcom: sa8775p: add cache coherency support for SA8775P | expand |
On 23.02.2024 15:03, Mrinmay Sarkar wrote: > Due to some hardware changes, SA8775P has set the NO_SNOOP attribute > in its TLP for all the PCIe controllers. NO_SNOOP attribute when set, > the requester is indicating that there no cache coherency issues exit > for the addressed memory on the host i.e., memory is not cached. But > in reality, requester cannot assume this unless there is a complete > control/visibility over the addressed memory on the host. > > And worst case, if the memory is cached on the host, it may lead to > memory corruption issues. It should be noted that the caching of memory > on the host is not solely dependent on the NO_SNOOP attribute in TLP. > > So to avoid the corruption, this patch overrides the NO_SNOOP attribute > by setting the PCIE_PARF_NO_SNOOP_OVERIDE register. This patch is not > needed for other upstream supported platforms since they do not set > NO_SNOOP attribute by default. > > Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com> > --- > drivers/pci/controller/dwc/pcie-qcom-ep.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c > index 89d06a3e6e06..369954649254 100644 > --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c > +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c > @@ -45,6 +45,7 @@ > #define PARF_SLV_ADDR_MSB_CTRL 0x2c0 > #define PARF_DBI_BASE_ADDR 0x350 > #define PARF_DBI_BASE_ADDR_HI 0x354 > +#define PARF_NO_SNOOP_OVERIDE 0x3d4 Any reason for this to be unsorted? Konrad
On 2/24/2024 5:37 AM, Konrad Dybcio wrote: > On 23.02.2024 15:03, Mrinmay Sarkar wrote: >> Due to some hardware changes, SA8775P has set the NO_SNOOP attribute >> in its TLP for all the PCIe controllers. NO_SNOOP attribute when set, >> the requester is indicating that there no cache coherency issues exit >> for the addressed memory on the host i.e., memory is not cached. But >> in reality, requester cannot assume this unless there is a complete >> control/visibility over the addressed memory on the host. >> >> And worst case, if the memory is cached on the host, it may lead to >> memory corruption issues. It should be noted that the caching of memory >> on the host is not solely dependent on the NO_SNOOP attribute in TLP. >> >> So to avoid the corruption, this patch overrides the NO_SNOOP attribute >> by setting the PCIE_PARF_NO_SNOOP_OVERIDE register. This patch is not >> needed for other upstream supported platforms since they do not set >> NO_SNOOP attribute by default. >> >> Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com> >> --- >> drivers/pci/controller/dwc/pcie-qcom-ep.c | 20 +++++++++++++++++--- >> 1 file changed, 17 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c >> index 89d06a3e6e06..369954649254 100644 >> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c >> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c >> @@ -45,6 +45,7 @@ >> #define PARF_SLV_ADDR_MSB_CTRL 0x2c0 >> #define PARF_DBI_BASE_ADDR 0x350 >> #define PARF_DBI_BASE_ADDR_HI 0x354 >> +#define PARF_NO_SNOOP_OVERIDE 0x3d4 > Any reason for this to be unsorted? > > Konrad Yes, this should be sorted. Will fix this in next series. Thanks Mrinmay
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c index 89d06a3e6e06..369954649254 100644 --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c @@ -45,6 +45,7 @@ #define PARF_SLV_ADDR_MSB_CTRL 0x2c0 #define PARF_DBI_BASE_ADDR 0x350 #define PARF_DBI_BASE_ADDR_HI 0x354 +#define PARF_NO_SNOOP_OVERIDE 0x3d4 #define PARF_SLV_ADDR_SPACE_SIZE 0x358 #define PARF_SLV_ADDR_SPACE_SIZE_HI 0x35c #define PARF_ATU_BASE_ADDR 0x634 @@ -86,6 +87,10 @@ #define PARF_DEBUG_INT_CFG_BUS_MASTER_EN BIT(2) #define PARF_DEBUG_INT_RADM_PM_TURNOFF BIT(3) +/* PARF_NO_SNOOP_OVERIDE register fields */ +#define WR_NO_SNOOP_OVERIDE_EN BIT(1) +#define RD_NO_SNOOP_OVERIDE_EN BIT(3) + /* PARF_DEVICE_TYPE register fields */ #define PARF_DEVICE_TYPE_EP 0x0 @@ -152,9 +157,11 @@ enum qcom_pcie_ep_link_status { /** * struct qcom_pcie_ep_cfg - Per SoC config struct * @hdma_support: HDMA support on this SoC + * @enable_cache_snoop: enable cache snooping on this SoC */ struct qcom_pcie_ep_cfg { bool hdma_support; + bool enable_cache_snoop; }; /** @@ -175,6 +182,7 @@ struct qcom_pcie_ep_cfg { * @num_clks: PCIe clocks count * @perst_en: Flag for PERST enable * @perst_sep_en: Flag for PERST separation enable + * @cfg: PCIe EP config struct * @link_status: PCIe Link status * @global_irq: Qualcomm PCIe specific Global IRQ * @perst_irq: PERST# IRQ @@ -202,6 +210,7 @@ struct qcom_pcie_ep { u32 perst_en; u32 perst_sep_en; + const struct qcom_pcie_ep_cfg *cfg; enum qcom_pcie_ep_link_status link_status; int global_irq; int perst_irq; @@ -497,6 +506,11 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci) val |= BIT(8); writel_relaxed(val, pcie_ep->parf + PARF_LTSSM); + /* Enable cache snooping for SA8775P */ + if (pcie_ep->cfg && pcie_ep->cfg->enable_cache_snoop) + writel_relaxed(WR_NO_SNOOP_OVERIDE_EN | RD_NO_SNOOP_OVERIDE_EN, + pcie_ep->parf + PARF_NO_SNOOP_OVERIDE); + return 0; err_disable_resources: @@ -811,7 +825,6 @@ static const struct dw_pcie_ep_ops pci_ep_ops = { static int qcom_pcie_ep_probe(struct platform_device *pdev) { - const struct qcom_pcie_ep_cfg *cfg; struct device *dev = &pdev->dev; struct qcom_pcie_ep *pcie_ep; char *name; @@ -826,8 +839,8 @@ static int qcom_pcie_ep_probe(struct platform_device *pdev) pcie_ep->pci.ep.ops = &pci_ep_ops; pcie_ep->pci.edma.nr_irqs = 1; - cfg = of_device_get_match_data(dev); - if (cfg && cfg->hdma_support) { + pcie_ep->cfg = of_device_get_match_data(dev); + if (pcie_ep->cfg && pcie_ep->cfg->hdma_support) { pcie_ep->pci.edma.ll_wr_cnt = 8; pcie_ep->pci.edma.ll_rd_cnt = 8; pcie_ep->pci.edma.mf = EDMA_MF_HDMA_NATIVE; @@ -893,6 +906,7 @@ static void qcom_pcie_ep_remove(struct platform_device *pdev) static const struct qcom_pcie_ep_cfg cfg_1_34_0 = { .hdma_support = true, + .enable_cache_snoop = true, }; static const struct of_device_id qcom_pcie_ep_match[] = {
Due to some hardware changes, SA8775P has set the NO_SNOOP attribute in its TLP for all the PCIe controllers. NO_SNOOP attribute when set, the requester is indicating that there no cache coherency issues exit for the addressed memory on the host i.e., memory is not cached. But in reality, requester cannot assume this unless there is a complete control/visibility over the addressed memory on the host. And worst case, if the memory is cached on the host, it may lead to memory corruption issues. It should be noted that the caching of memory on the host is not solely dependent on the NO_SNOOP attribute in TLP. So to avoid the corruption, this patch overrides the NO_SNOOP attribute by setting the PCIE_PARF_NO_SNOOP_OVERIDE register. This patch is not needed for other upstream supported platforms since they do not set NO_SNOOP attribute by default. Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com> --- drivers/pci/controller/dwc/pcie-qcom-ep.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)