From: Tim Harvey <tharvey@gateworks.com>
Date: Fri, 8 Aug 2014 05:57:29 +0000 (-0700)
Subject: pci: mx6: fix occasional link failures
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=5a82e1a21d1229e7e3d1c64187735794019e9a1b;p=u-boot.git

pci: mx6: fix occasional link failures

According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable
for SS function) must remain deasserted until the reference clock is running
at the appropriate frequency.

Without this patch we find a high link failure rate (>5%) on certain
IMX6 boards at various temperatures.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
---

diff --git a/drivers/pci/pcie_imx.c b/drivers/pci/pcie_imx.c
index c48737e6c9..a3982c4553 100644
--- a/drivers/pci/pcie_imx.c
+++ b/drivers/pci/pcie_imx.c
@@ -509,10 +509,6 @@ static int imx6_pcie_deassert_core_reset(void)
 
 	imx6_pcie_toggle_power();
 
-	/* Enable PCIe */
-	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
-	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
-
 	enable_pcie_clock();
 
 	/*
@@ -521,6 +517,10 @@ static int imx6_pcie_deassert_core_reset(void)
 	 */
 	mdelay(50);
 
+	/* Enable PCIe */
+	clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
+	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
+
 	imx6_pcie_toggle_reset();
 
 	return 0;