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Message-Id: <20231129214412.327633-3-Frank.Li@nxp.com>
Date: Wed, 29 Nov 2023 16:44:10 -0500
From: Frank Li <Frank.Li@....com>
To: manivannan.sadhasivam@...aro.org
Cc: Frank.Li@....com, bhelgaas@...gle.com, imx@...ts.linux.dev,
kw@...ux.com, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, lpieralisi@...nel.org,
minghuan.Lian@....com, mingkai.hu@....com, robh@...nel.org,
roy.zang@....com
Subject: [PATCH v4 2/4] PCI: layerscape: Add suspend/resume for ls1021a
ls1021a add suspend/resume support.
In the suspend path, PME_Turn_Off message is sent to the endpoint to
transition the link to L2/L3_Ready state. In this SoC, there is no way to
check if the controller has received the PME_To_Ack from the endpoint or
not. So to be on the safer side, the driver just waits for
PCIE_PME_TO_L2_TIMEOUT_US before asserting the SoC specific PMXMTTURNOFF
bit to complete the PME_Turn_Off handshake. This link would then enter
L2/L3 state depending on the VAUX supply.
In the resume path, the link is brought back from L2 to L0 by doing a
software reset.
Signed-off-by: Frank Li <Frank.Li@....com>
---
Notes:
Change from v3 to v4
- update commit message.
- it is reset a glue logic part for PCI controller.
- use regmap_write_bits() to reduce code change.
Change from v2 to v3
- update according to mani's feedback
change from v1 to v2
- change subject 'a' to 'A'
drivers/pci/controller/dwc/pci-layerscape.c | 83 ++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
index aea89926bcc4f..42bca2c3b5c3e 100644
--- a/drivers/pci/controller/dwc/pci-layerscape.c
+++ b/drivers/pci/controller/dwc/pci-layerscape.c
@@ -35,11 +35,19 @@
#define PF_MCR_PTOMR BIT(0)
#define PF_MCR_EXL2S BIT(1)
+/* LS1021A PEXn PM Write Control Register */
+#define SCFG_PEXPMWRCR(idx) (0x5c + (idx) * 0x64)
+#define PMXMTTURNOFF BIT(31)
+#define SCFG_PEXSFTRSTCR 0x190
+#define PEXSR(idx) BIT(idx)
+
#define PCIE_IATU_NUM 6
struct ls_pcie_drvdata {
const u32 pf_off;
+ const struct dw_pcie_host_ops *ops;
int (*exit_from_l2)(struct dw_pcie_rp *pp);
+ bool scfg_support;
bool pm_support;
};
@@ -47,6 +55,8 @@ struct ls_pcie {
struct dw_pcie *pci;
const struct ls_pcie_drvdata *drvdata;
void __iomem *pf_base;
+ struct regmap *scfg;
+ int index;
bool big_endian;
};
@@ -171,13 +181,65 @@ static int ls_pcie_host_init(struct dw_pcie_rp *pp)
return 0;
}
+static void scfg_pcie_send_turnoff_msg(struct regmap *scfg, u32 reg, u32 mask)
+{
+ /* Send PME_Turn_Off message */
+ regmap_write_bits(scfg, reg, mask, mask);
+
+ /*
+ * There is no specific register to check for PME_To_Ack from endpoint.
+ * So on the safe side, wait for PCIE_PME_TO_L2_TIMEOUT_US.
+ */
+ mdelay(PCIE_PME_TO_L2_TIMEOUT_US/1000);
+
+ /*
+ * Layerscape hardware reference manual recommends clearing the PMXMTTURNOFF bit
+ * to complete the PME_Turn_Off handshake.
+ */
+ regmap_write_bits(scfg, reg, mask, 0);
+}
+
+static void ls1021a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct ls_pcie *pcie = to_ls_pcie(pci);
+
+ scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMWRCR(pcie->index), PMXMTTURNOFF);
+}
+
+static int scfg_pcie_exit_from_l2(struct regmap *scfg, u32 reg, u32 mask)
+{
+ /* Only way exit from l2 is that do software reset */
+ regmap_write_bits(scfg, reg, mask, mask);
+
+ regmap_write_bits(scfg, reg, mask, 0);
+
+ return 0;
+}
+
+static int ls1021a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct ls_pcie *pcie = to_ls_pcie(pci);
+
+ return scfg_pcie_exit_from_l2(pcie->scfg, SCFG_PEXSFTRSTCR, PEXSR(pcie->index));
+}
+
static const struct dw_pcie_host_ops ls_pcie_host_ops = {
.host_init = ls_pcie_host_init,
.pme_turn_off = ls_pcie_send_turnoff_msg,
};
+static const struct dw_pcie_host_ops ls1021a_pcie_host_ops = {
+ .host_init = ls_pcie_host_init,
+ .pme_turn_off = ls1021a_pcie_send_turnoff_msg,
+};
+
static const struct ls_pcie_drvdata ls1021a_drvdata = {
- .pm_support = false,
+ .pm_support = true,
+ .scfg_support = true,
+ .ops = &ls1021a_pcie_host_ops,
+ .exit_from_l2 = ls1021a_pcie_exit_from_l2,
};
static const struct ls_pcie_drvdata layerscape_drvdata = {
@@ -205,6 +267,8 @@ static int ls_pcie_probe(struct platform_device *pdev)
struct dw_pcie *pci;
struct ls_pcie *pcie;
struct resource *dbi_base;
+ u32 index[2];
+ int ret;
pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
if (!pcie)
@@ -220,6 +284,7 @@ static int ls_pcie_probe(struct platform_device *pdev)
pci->pp.ops = &ls_pcie_host_ops;
pcie->pci = pci;
+ pci->pp.ops = pcie->drvdata->ops ? pcie->drvdata->ops : &ls_pcie_host_ops;
dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
@@ -230,6 +295,22 @@ static int ls_pcie_probe(struct platform_device *pdev)
pcie->pf_base = pci->dbi_base + pcie->drvdata->pf_off;
+ if (pcie->drvdata->scfg_support) {
+ pcie->scfg = syscon_regmap_lookup_by_phandle(dev->of_node, "fsl,pcie-scfg");
+ if (IS_ERR(pcie->scfg)) {
+ dev_err(dev, "No syscfg phandle specified\n");
+ return PTR_ERR(pcie->scfg);
+ }
+
+ ret = of_property_read_u32_array(dev->of_node, "fsl,pcie-scfg", index, 2);
+ if (ret) {
+ pcie->scfg = NULL;
+ return ret;
+ }
+
+ pcie->index = index[1];
+ }
+
if (!ls_pcie_is_bridge(pcie))
return -ENODEV;
--
2.34.1
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