[PATCH 3/3] PCI: qcom: Add D3cold support

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

Add pme_turn_off() support and use DWC common suspend resume methods
for device D3cold entry & exit. If the device is not kept in D3cold
use existing methods like keeping icc votes, opp votes etc.. intact.

In qcom_pcie_deinit_2_7_0(), explicitly disable PCIe clocks and resets
in the controller.

Remove suspended flag from qcom_pcie structure as it is no longer needed.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 114 ++++++++++++++++++++-------------
 1 file changed, 68 insertions(+), 46 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 7b92e7a1c0d9364a9cefe1450818f9cbfc7fd3ac..bb4e5a29c452a6c0d4b31b2a9ff3aa62b984fb64 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -150,6 +150,7 @@
 
 /* ELBI_SYS_CTRL register fields */
 #define ELBI_SYS_CTRL_LT_ENABLE			BIT(0)
+#define ELBI_SYS_CTRL_PME_TURNOFF_MSG		BIT(4)
 
 /* AXI_MSTR_RESP_COMP_CTRL0 register fields */
 #define CFG_REMOTE_RD_REQ_BRIDGE_SIZE_2K	0x4
@@ -283,7 +284,6 @@ struct qcom_pcie {
 	const struct qcom_pcie_cfg *cfg;
 	struct dentry *debugfs;
 	struct list_head ports;
-	bool suspended;
 	bool use_pm_opp;
 };
 
@@ -1075,6 +1075,12 @@ static void qcom_pcie_host_post_init_2_7_0(struct qcom_pcie *pcie)
 static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie)
 {
 	struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
+	u32 val;
+
+	/* Disable PCIe clocks and resets */
+	val = readl(pcie->parf + PARF_PHY_CTRL);
+	val |= PHY_TEST_PWR_DOWN;
+	writel(val, pcie->parf + PARF_PHY_CTRL);
 
 	clk_bulk_disable_unprepare(res->num_clks, res->clks);
 
@@ -1355,10 +1361,18 @@ static void qcom_pcie_host_post_init(struct dw_pcie_rp *pp)
 		pcie->cfg->ops->host_post_init(pcie);
 }
 
+static void qcom_pcie_host_pme_turn_off(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+
+	writel(ELBI_SYS_CTRL_PME_TURNOFF_MSG, pci->elbi_base + ELBI_SYS_CTRL);
+}
+
 static const struct dw_pcie_host_ops qcom_pcie_dw_ops = {
 	.init		= qcom_pcie_host_init,
 	.deinit		= qcom_pcie_host_deinit,
 	.post_init	= qcom_pcie_host_post_init,
+	.pme_turn_off	= qcom_pcie_host_pme_turn_off,
 };
 
 /* Qcom IP rev.: 2.1.0	Synopsys IP rev.: 4.01a */
@@ -2016,53 +2030,51 @@ static int qcom_pcie_suspend_noirq(struct device *dev)
 	if (!pcie)
 		return 0;
 
-	/*
-	 * Set minimum bandwidth required to keep data path functional during
-	 * suspend.
-	 */
-	if (pcie->icc_mem) {
-		ret = icc_set_bw(pcie->icc_mem, 0, kBps_to_icc(1));
-		if (ret) {
-			dev_err(dev,
-				"Failed to set bandwidth for PCIe-MEM interconnect path: %d\n",
-				ret);
-			return ret;
-		}
-	}
+	ret = dw_pcie_suspend_noirq(pcie->pci);
+	if (ret)
+		return ret;
 
-	/*
-	 * Turn OFF the resources only for controllers without active PCIe
-	 * devices. For controllers with active devices, the resources are kept
-	 * ON and the link is expected to be in L0/L1 (sub)states.
-	 *
-	 * Turning OFF the resources for controllers with active PCIe devices
-	 * will trigger access violation during the end of the suspend cycle,
-	 * as kernel tries to access the PCIe devices config space for masking
-	 * MSIs.
-	 *
-	 * Also, it is not desirable to put the link into L2/L3 state as that
-	 * implies VDD supply will be removed and the devices may go into
-	 * powerdown state. This will affect the lifetime of the storage devices
-	 * like NVMe.
-	 */
-	if (!dw_pcie_link_up(pcie->pci)) {
-		qcom_pcie_host_deinit(&pcie->pci->pp);
-		pcie->suspended = true;
-	}
+	if (pcie->pci->suspended) {
+		ret = icc_disable(pcie->icc_mem);
+		if (ret)
+			dev_err(dev, "Failed to disable PCIe-MEM interconnect path: %d\n", ret);
 
-	/*
-	 * Only disable CPU-PCIe interconnect path if the suspend is non-S2RAM.
-	 * Because on some platforms, DBI access can happen very late during the
-	 * S2RAM and a non-active CPU-PCIe interconnect path may lead to NoC
-	 * error.
-	 */
-	if (pm_suspend_target_state != PM_SUSPEND_MEM) {
 		ret = icc_disable(pcie->icc_cpu);
 		if (ret)
 			dev_err(dev, "Failed to disable CPU-PCIe interconnect path: %d\n", ret);
 
 		if (pcie->use_pm_opp)
 			dev_pm_opp_set_opp(pcie->pci->dev, NULL);
+	} else {
+		/*
+		 * Set minimum bandwidth required to keep data path functional during
+		 * suspend.
+		 */
+		if (pcie->icc_mem) {
+			ret = icc_set_bw(pcie->icc_mem, 0, kBps_to_icc(1));
+			if (ret) {
+				dev_err(dev,
+					"Failed to set bandwidth for PCIe-MEM interconnect path: %d\n",
+					ret);
+				return ret;
+			}
+		}
+
+		/*
+		 * Only disable CPU-PCIe interconnect path if the suspend is non-S2RAM.
+		 * Because on some platforms, DBI access can happen very late during the
+		 * S2RAM and a non-active CPU-PCIe interconnect path may lead to NoC
+		 * error.
+		 */
+		if (pm_suspend_target_state != PM_SUSPEND_MEM) {
+			ret = icc_disable(pcie->icc_cpu);
+			if (ret)
+				dev_err(dev, "Failed to disable CPU-PCIe interconnect path: %d\n",
+					ret);
+
+			if (pcie->use_pm_opp)
+				dev_pm_opp_set_opp(pcie->pci->dev, NULL);
+		}
 	}
 	return ret;
 }
@@ -2076,20 +2088,30 @@ static int qcom_pcie_resume_noirq(struct device *dev)
 	if (!pcie)
 		return 0;
 
-	if (pm_suspend_target_state != PM_SUSPEND_MEM) {
+	if (pcie->pci->suspended) {
 		ret = icc_enable(pcie->icc_cpu);
 		if (ret) {
 			dev_err(dev, "Failed to enable CPU-PCIe interconnect path: %d\n", ret);
 			return ret;
 		}
-	}
 
-	if (pcie->suspended) {
-		ret = qcom_pcie_host_init(&pcie->pci->pp);
+		ret = icc_enable(pcie->icc_mem);
+		if (ret) {
+			dev_err(dev, "Failed to enable PCIe-MEM interconnect path: %d\n", ret);
+			return ret;
+		}
+		ret = dw_pcie_resume_noirq(pcie->pci);
 		if (ret)
 			return ret;
-
-		pcie->suspended = false;
+	} else {
+		if (pm_suspend_target_state != PM_SUSPEND_MEM) {
+			ret = icc_enable(pcie->icc_cpu);
+			if (ret) {
+				dev_err(dev, "Failed to enable CPU-PCIe interconnect path: %d\n",
+					ret);
+				return ret;
+			}
+		}
 	}
 
 	qcom_pcie_icc_opp_update(pcie);

-- 
2.34.1