[PATCH v3 06/12] PCI: qcom-ep: Gate Master AXI clock to MHI bus during L1SS

Manivannan Sadhasivam
2022-09-10T06:32:27Z

During L1SS, gate the Master clock supplied to the MHI bus to save power.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/pci/controller/dwc/pcie-qcom-ep.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 2dc6d4e44aff..526e98ea23f6 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -27,6 +27,7 @@
#define PARF_SYS_CTRL 0x00
#define PARF_DB_CTRL 0x10
#define PARF_PM_CTRL 0x20
+#define PARF_MHI_CLOCK_RESET_CTRL 0x174
#define PARF_MHI_BASE_ADDR_LOWER 0x178
#define PARF_MHI_BASE_ADDR_UPPER 0x17c
#define PARF_DEBUG_INT_EN 0x190
@@ -89,6 +90,9 @@
#define PARF_PM_CTRL_READY_ENTR_L23 BIT(2)
#define PARF_PM_CTRL_REQ_NOT_ENTR_L1 BIT(5)

+/* PARF_MHI_CLOCK_RESET_CTRL fields */
+#define PARF_MSTR_AXI_CLK_EN BIT(1)
+
/* PARF_AXI_MSTR_RD_HALT_NO_WRITES register fields */
#define PARF_AXI_MSTR_RD_HALT_NO_WRITE_EN BIT(0)

@@ -394,6 +398,11 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
pcie_ep->parf + PARF_MHI_BASE_ADDR_LOWER);
writel_relaxed(0, pcie_ep->parf + PARF_MHI_BASE_ADDR_UPPER);

+ /* Gate Master AXI clock to MHI bus during L1SS */
+ val = readl_relaxed(pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
+ val &= ~PARF_MSTR_AXI_CLK_EN;
+ val = readl_relaxed(pcie_ep->parf + PARF_MHI_CLOCK_RESET_CTRL);
+
dw_pcie_ep_init_notify(&pcie_ep->pci.ep);

/* Enable LTSSM */
--
2.25.1