[PATCH v2] PCI: rcar: Fix writing the MACCTLR register value

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According to the R-Car Gen2/3 manual, the bit 0 of MACCTLR register
should be written to 0 because the register is set to 1 on reset.
To avoid unexpected behaviors from this incorrect setting, this
patch fixes it.

Fixes: b3327f7fae66 ("PCI: rcar: Try increasing PCIe link speed to 5 GT/s at boot")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.9+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
---
 Changes from v1:
 - Fix commit log.
 - Add Sergei-san's Reviewed-by.
 https://patchwork.kernel.org/patch/11179279/

 drivers/pci/controller/pcie-rcar.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index f6a669a..9eb9b25 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -93,6 +93,7 @@
 #define  LINK_SPEED_2_5GTS	(1 << 16)
 #define  LINK_SPEED_5_0GTS	(2 << 16)
 #define MACCTLR			0x011058
+#define  MACCTLR_RESERVED	BIT(0)
 #define  SPEED_CHANGE		BIT(24)
 #define  SCRAMBLE_DISABLE	BIT(27)
 #define PMSR			0x01105c
@@ -427,7 +428,8 @@ static void rcar_pcie_force_speedup(struct rcar_pcie *pcie)
 		rcar_pci_write_reg(pcie, macsr, MACSR);
 
 	/* Start link speed change */
-	rcar_rmw32(pcie, MACCTLR, SPEED_CHANGE, SPEED_CHANGE);
+	rcar_rmw32(pcie, MACCTLR, SPEED_CHANGE | MACCTLR_RESERVED,
+		   SPEED_CHANGE);
 
 	while (timeout--) {
 		macsr = rcar_pci_read_reg(pcie, MACSR);
-- 
2.7.4




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