On 6/20/2024 2:34 PM, Prudhvi Yarlagadda wrote:
PARF hardware block which is a wrapper on top of DWC PCIe controller
mirrors the DBI and ATU register space. It uses PARF_SLV_ADDR_SPACE_SIZE
register to get the size of the memory block to be mirrored and uses
PARF_DBI_BASE_ADDR, PARF_ATU_BASE_ADDR registers to determine the base
address of DBI and ATU space inside the memory block that is being
mirrored.
When a memory region which is located above the SLV_ADDR_SPACE_SIZE
boundary is used for BAR region then there could be an overlap of DBI and
ATU address space that is getting mirrored and the BAR region. This
results in DBI and ATU address space contents getting updated when a PCIe
function driver tries updating the BAR/MMIO memory region. Reference
memory map of the PCIe memory region with DBI and ATU address space
overlapping BAR region is as below.
|---------------|
| |
| |
------- --------|---------------|
| | |---------------|
| | | DBI |
| | |---------------|---->DBI_BASE_ADDR
| | | |
| | | |
| PCIe | |---->2*SLV_ADDR_SPACE_SIZE
| BAR/MMIO|---------------|
| Region | ATU |
| | |---------------|---->ATU_BASE_ADDR
| | | |
PCIe | |---------------|
Memory | | DBI |
Region | |---------------|---->DBI_BASE_ADDR
| | | |
| --------| |
| | |---->SLV_ADDR_SPACE_SIZE
| |---------------|
| | ATU |
| |---------------|---->ATU_BASE_ADDR
| | |
| |---------------|
| | DBI |
| |---------------|---->DBI_BASE_ADDR
| | |
| | |
----------------|---------------|
| |
| |
| |
|---------------|
Currently memory region beyond the SLV_ADDR_SPACE_SIZE boundary is not
used for BAR region which is why the above mentioned issue is not
encountered. This issue is discovered as part of internal testing when we
tried moving the BAR region beyond the SLV_ADDR_SPACE_SIZE boundary. Hence
we are trying to fix this.
As PARF hardware block mirrors DBI and ATU register space after every
PARF_SLV_ADDR_SPACE_SIZE (default 0x1000000) boundary multiple, write
U64_MAX to PARF_SLV_ADDR_SPACE_SIZE register to avoid mirroring DBI and
ATU to BAR/MMIO region. Write the physical base address of DBI and ATU
register blocks to PARF_DBI_BASE_ADDR (default 0x0) and PARF_ATU_BASE_ADDR
(default 0x1000) respectively to make sure DBI and ATU blocks are at
expected memory locations.
Signed-off-by: Prudhvi Yarlagadda <quic_pyarlaga@xxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-qcom.c | 40 ++++++++++++++++++++++----
1 file changed, 35 insertions(+), 5 deletions(-)
Tested:
- Validated NVME functionality with PCIe6a on x1e80100 platform.
- Validated WiFi functionality with PCIe4 on x1e80100 platform.
- Validated NVME functionality with PCIe0 and PCIe1 on SA8775p platform.
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 5f9f0ff19baa..864548657551 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -49,7 +49,12 @@
#define PARF_LTSSM 0x1b0
#define PARF_SID_OFFSET 0x234
#define PARF_BDF_TRANSLATE_CFG 0x24c
+#define PARF_DBI_BASE_ADDR_V2 0x350
+#define PARF_DBI_BASE_ADDR_V2_HI 0x354
#define PARF_SLV_ADDR_SPACE_SIZE 0x358
+#define PARF_SLV_ADDR_SPACE_SIZE_HI 0x35C
+#define PARF_ATU_BASE_ADDR 0x634
+#define PARF_ATU_BASE_ADDR_HI 0x638
#define PARF_NO_SNOOP_OVERIDE 0x3d4
#define PARF_DEVICE_TYPE 0x1000
#define PARF_BDF_TO_SID_TABLE_N 0x2000
@@ -319,6 +324,33 @@ static void qcom_pcie_clear_hpc(struct dw_pcie *pci)
dw_pcie_dbi_ro_wr_dis(pci);
}
+static void qcom_pcie_avoid_dbi_atu_mirroring(struct qcom_pcie *pcie)
+{
+ struct dw_pcie *pci = pcie->pci;
+ struct platform_device *pdev;
+ struct resource *atu_res;
+ struct resource *dbi_res;
+
+ pdev = to_platform_device(pci->dev);
+ if (!pdev)
+ return;
+
+ dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+ if (dbi_res) {
+ writel(lower_32_bits(dbi_res->start), pcie->parf + PARF_DBI_BASE_ADDR_V2);
+ writel(upper_32_bits(dbi_res->start), pcie->parf + PARF_DBI_BASE_ADDR_V2_HI);
+ }
+
+ atu_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "atu");
+ if (atu_res) {
+ writel(lower_32_bits(atu_res->start), pcie->parf + PARF_ATU_BASE_ADDR);
+ writel(upper_32_bits(atu_res->start), pcie->parf + PARF_ATU_BASE_ADDR_HI);
+ }
+
+ writel(lower_32_bits(U64_MAX), pcie->parf + PARF_SLV_ADDR_SPACE_SIZE);
+ writel(upper_32_bits(U64_MAX), pcie->parf + PARF_SLV_ADDR_SPACE_SIZE_HI);
+}
+
static void qcom_pcie_2_1_0_ltssm_enable(struct qcom_pcie *pcie)
{
u32 val;
@@ -623,8 +655,7 @@ static int qcom_pcie_post_init_2_3_2(struct qcom_pcie *pcie)
val &= ~PHY_TEST_PWR_DOWN;
writel(val, pcie->parf + PARF_PHY_CTRL);
- /* change DBI base address */
- writel(0, pcie->parf + PARF_DBI_BASE_ADDR);
+ qcom_pcie_avoid_dbi_atu_mirroring(pcie);
/* MAC PHY_POWERDOWN MUX DISABLE */
val = readl(pcie->parf + PARF_SYS_CTRL);
@@ -900,6 +931,8 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
/* Wait for reset to complete, required on SM8450 */
usleep_range(1000, 1500);
+ qcom_pcie_avoid_dbi_atu_mirroring(pcie);
+
/* configure PCIe to RC mode */
writel(DEVICE_TYPE_RC, pcie->parf + PARF_DEVICE_TYPE);
@@ -908,9 +941,6 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
val &= ~PHY_TEST_PWR_DOWN;
writel(val, pcie->parf + PARF_PHY_CTRL);
- /* change DBI base address */
- writel(0, pcie->parf + PARF_DBI_BASE_ADDR);
-
/* MAC PHY_POWERDOWN MUX DISABLE */
val = readl(pcie->parf + PARF_SYS_CTRL);
val &= ~MAC_PHY_POWERDOWN_IN_P2_D_MUX_EN;
Reviewed-by: Mayank Rana <quic_mrana@xxxxxxxxxxx>
