According to the R-Car Gen2/3 manual, "Be sure to write the initial
value (= H'80FF 0000) to MACCTLR before enabling PCIETCTLR.CFINIT".
To avoid unexpected behaviors, this patch fixes it. Note that
the SPCHG bit of MACCTLR register description said "Only writing 1
is valid and writing 0 is invalid" but this "invalid" means
"ignored", not "prohibited". So, any documentation conflict doesn't
exist about writing the MACCTLR register.
Reported-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Fixes: c25da4778803 ("PCI: rcar: Add Renesas R-Car PCIe driver")
Fixes: be20bbcb0a8c ("PCI: rcar: Add the initialization of PCIe link in resume_noirq()")
Cc: <stable@xxxxxxxxxxxxxxx> # v5.2+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
drivers/pci/controller/pcie-rcar.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index 40d8c54..1bfec1f 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -91,8 +91,12 @@
#define LINK_SPEED_2_5GTS (1 << 16)
#define LINK_SPEED_5_0GTS (2 << 16)
#define MACCTLR 0x011058
+#define MACCTLR_RESERVED23_16 GENMASK(23, 16)
#define SPEED_CHANGE BIT(24)
#define SCRAMBLE_DISABLE BIT(27)
+#define LTSMDIS BIT(31)
+ /* Be sure to write the initial value (H'80FF 0000) to MACCTLR */
+#define MACCTLR_INIT_VAL (LTSMDIS | MACCTLR_RESERVED23_16)
#define PMSR 0x01105c
#define MACS2R 0x011078
#define MACCGSPSETR 0x011084
@@ -613,6 +617,8 @@ static int rcar_pcie_hw_init(struct rcar_pcie *pcie)
if (IS_ENABLED(CONFIG_PCI_MSI))
rcar_pci_write_reg(pcie, 0x801f0000, PCIEMSITXR);
+ rcar_pci_write_reg(pcie, MACCTLR_INIT_VAL, MACCTLR);
+
/* Finish initialization - establish a PCI Express link */
rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
@@ -1235,6 +1241,7 @@ static int rcar_pcie_resume_noirq(struct device *dev)
return 0;
/* Re-establish the PCIe link */
+ rcar_pci_write_reg(pcie, MACCTLR_INIT_VAL, MACCTLR);
rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
return rcar_pcie_wait_for_dl(pcie);
}
--
2.7.4
