[PATCH v2 0/3] arm64: qcom: sa8775p: add cache coherency support for SA8775P

[PATCH v2 0/3] arm64: qcom: sa8775p: add cache coherency support for SA8775P

[Mrinmay Sarkar]

In a multiprocessor system cache snooping maintains the consistency
of caches. Snooping logic is disabled from HW on this platform.
Cache coherency doesn’t work without enabling this logic.

This series is to enable cache snooping logic in both RC and EP
driver and add the "dma-coherent" property in dtsi to support
cache coherency in 8775 platform.

To verify this series we required [1]

[1] https://lore.kernel.org/all/1699669982-7691-1-git-send-email-quic_msarkar@quicinc.com/

v1 -> v2:
- update cover letter with explanation.
- define each of these bits and ORing at usage time rather than
  directly writing value in register. 

Mrinmay Sarkar (3):
  PCI: qcom: Enable cache coherency for SA8775P RC
  PCI: qcom-ep: Enable cache coherency for SA8775P EP
  arm64: dts: qcom: sa8775p: Mark PCIe controller as cache coherent

 arch/arm64/boot/dts/qcom/sa8775p.dtsi     |  1 +
 drivers/pci/controller/dwc/pcie-qcom-ep.c | 10 ++++++++++
 drivers/pci/controller/dwc/pcie-qcom.c    | 13 +++++++++++++
 3 files changed, 24 insertions(+)

-- 
2.7.4

[PATCH v2 1/3] PCI: qcom: Enable cache coherency for SA8775P RC

[Mrinmay Sarkar]

This change will enable cache snooping logic to support
cache coherency for 8755 RC platform.

Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 6902e97..b82ccd1 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -51,6 +51,7 @@
 #define PARF_SID_OFFSET				0x234
 #define PARF_BDF_TRANSLATE_CFG			0x24c
 #define PARF_SLV_ADDR_SPACE_SIZE		0x358
+#define PCIE_PARF_NO_SNOOP_OVERIDE		0x3d4
 #define PARF_DEVICE_TYPE			0x1000
 #define PARF_BDF_TO_SID_TABLE_N			0x2000
 
@@ -117,6 +118,10 @@
 /* PARF_LTSSM register fields */
 #define LTSSM_EN				BIT(8)
 
+/* 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 DEVICE_TYPE_RC				0x4
 
@@ -961,6 +966,14 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
 
 static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
 {
+	struct dw_pcie *pci = pcie->pci;
+	struct device *dev = pci->dev;
+
+	/* Enable cache snooping for SA8775P */
+	if (of_device_is_compatible(dev->of_node, "qcom,pcie-sa8775p"))
+		writel(WR_NO_SNOOP_OVERIDE_EN | RD_NO_SNOOP_OVERIDE_EN,
+				pcie->parf + PCIE_PARF_NO_SNOOP_OVERIDE);
+
 	qcom_pcie_clear_hpc(pcie->pci);
 
 	return 0;
-- 
2.7.4

[PATCH v2 2/3] PCI: qcom-ep: Enable cache coherency for SA8775P EP

[Mrinmay Sarkar]

This change will enable cache snooping logic to support
cache coherency for 8755 EP platform.

Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
---
 drivers/pci/controller/dwc/pcie-qcom-ep.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 3a53d97..ee99fb1 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -47,6 +47,7 @@
 #define PARF_DBI_BASE_ADDR_HI			0x354
 #define PARF_SLV_ADDR_SPACE_SIZE		0x358
 #define PARF_SLV_ADDR_SPACE_SIZE_HI		0x35c
+#define PCIE_PARF_NO_SNOOP_OVERIDE		0x3d4
 #define PARF_ATU_BASE_ADDR			0x634
 #define PARF_ATU_BASE_ADDR_HI			0x638
 #define PARF_SRIS_MODE				0x644
@@ -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
 
@@ -489,6 +494,11 @@ 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 (of_device_is_compatible(dev->of_node, "qcom,sa8775p-pcie-ep"))
+		writel_relaxed(WR_NO_SNOOP_OVERIDE_EN | RD_NO_SNOOP_OVERIDE_EN,
+				pcie_ep->parf + PCIE_PARF_NO_SNOOP_OVERIDE);
+
 	return 0;
 
 err_disable_resources:
-- 
2.7.4

[PATCH v2 3/3] arm64: dts: qcom: sa8775p: Mark PCIe controller as cache coherent

[Mrinmay Sarkar]

The PCIe controller on SA8775P supports cache coherency, hence add the
"dma-coherent" property to mark it as such.

Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
---
 arch/arm64/boot/dts/qcom/sa8775p.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/qcom/sa8775p.dtsi b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
index 7eab458..ab01efe 100644
--- a/arch/arm64/boot/dts/qcom/sa8775p.dtsi
+++ b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
@@ -3620,6 +3620,7 @@
 				<&gem_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_PCIE_0 0>;
 		interconnect-names = "pcie-mem", "cpu-pcie";
 
+		dma-coherent;
 		iommus = <&pcie_smmu 0x0000 0x7f>;
 		resets = <&gcc GCC_PCIE_0_BCR>;
 		reset-names = "core";
-- 
2.7.4