Add suspend/resume support for Layerscape LS1043a.
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. Then the link would 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@xxxxxxx>
---
Notes:
Change from v4 to v5
- update commit message
- use comments
/* Reset the PEX wrapper to bring the link out of L2 */
Change from v3 to v4
- Call scfg_pcie_send_turnoff_msg() shared with ls1021a
- update commit message
Change from v2 to v3
- Remove ls_pcie_lut_readl(writel) function
Change from v1 to v2
- Update subject 'a' to 'A'
drivers/pci/controller/dwc/pci-layerscape.c | 63 ++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
index a9151e98fde6f..715365e91f8ef 100644
--- a/drivers/pci/controller/dwc/pci-layerscape.c
+++ b/drivers/pci/controller/dwc/pci-layerscape.c
@@ -41,6 +41,15 @@
#define SCFG_PEXSFTRSTCR 0x190
#define PEXSR(idx) BIT(idx)
+/* LS1043A PEX PME control register */
+#define SCFG_PEXPMECR 0x144
+#define PEXPME(idx) BIT(31 - (idx) * 4)
+
+/* LS1043A PEX LUT debug register */
+#define LS_PCIE_LDBG 0x7fc
+#define LDBG_SR BIT(30)
+#define LDBG_WE BIT(31)
+
#define PCIE_IATU_NUM 6
struct ls_pcie_drvdata {
@@ -224,6 +233,45 @@ static int ls1021a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
return scfg_pcie_exit_from_l2(pcie->scfg, SCFG_PEXSFTRSTCR, PEXSR(pcie->index));
}
+static void ls1043a_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_PEXPMECR, PEXPME(pcie->index));
+}
+
+static int ls1043a_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);
+ u32 val;
+
+ /*
+ * Reset the PEX wrapper to bring the link out of L2.
+ * LDBG_WE: allows the user to have write access to the PEXDBG[SR] for both setting and
+ * clearing the soft reset on the PEX module.
+ * LDBG_SR: When SR is set to 1, the PEX module enters soft reset.
+ */
+ val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
+ val |= LDBG_WE;
+ ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
+
+ val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
+ val |= LDBG_SR;
+ ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
+
+ val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
+ val &= ~LDBG_SR;
+ ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
+
+ val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
+ val &= ~LDBG_WE;
+ ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
+
+ return 0;
+}
+
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,
@@ -241,6 +289,19 @@ static const struct ls_pcie_drvdata ls1021a_drvdata = {
.exit_from_l2 = ls1021a_pcie_exit_from_l2,
};
+static const struct dw_pcie_host_ops ls1043a_pcie_host_ops = {
+ .host_init = ls_pcie_host_init,
+ .pme_turn_off = ls1043a_pcie_send_turnoff_msg,
+};
+
+static const struct ls_pcie_drvdata ls1043a_drvdata = {
+ .pf_lut_off = 0x10000,
+ .pm_support = true,
+ .scfg_support = true,
+ .ops = &ls1043a_pcie_host_ops,
+ .exit_from_l2 = ls1043a_pcie_exit_from_l2,
+};
+
static const struct ls_pcie_drvdata layerscape_drvdata = {
.pf_lut_off = 0xc0000,
.pm_support = true,
@@ -252,7 +313,7 @@ static const struct of_device_id ls_pcie_of_match[] = {
{ .compatible = "fsl,ls1012a-pcie", .data = &layerscape_drvdata },
{ .compatible = "fsl,ls1021a-pcie", .data = &ls1021a_drvdata },
{ .compatible = "fsl,ls1028a-pcie", .data = &layerscape_drvdata },
- { .compatible = "fsl,ls1043a-pcie", .data = &ls1021a_drvdata },
+ { .compatible = "fsl,ls1043a-pcie", .data = &ls1043a_drvdata },
{ .compatible = "fsl,ls1046a-pcie", .data = &layerscape_drvdata },
{ .compatible = "fsl,ls2080a-pcie", .data = &layerscape_drvdata },
{ .compatible = "fsl,ls2085a-pcie", .data = &layerscape_drvdata },
--
2.34.1
