pci: pcie_imx: Fix hang on mx6qp

PCI driver currently hangs on mx6qp.

Toggle the reset bit with the appropriate timings to fix the issue.

Based on the FSL kernel driver implementation.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>

arch/arm/include/asm/arch-mx6/iomux.h

@@ -18,6 +18,8 @@
 #define IOMUXC_GPR1_REF_SSP_EN			(1 << 16)
 #define IOMUXC_GPR1_TEST_POWERDOWN		(1 << 18)
 
+#define IOMUXC_GPR1_PCIE_SW_RST		(1 << 29)
+
 /*
  * IOMUXC_GPR5 bit fields
  */

drivers/pci/pcie_imx.c

@@ -19,6 +19,7 @@
 #include <asm/io.h>
 #include <linux/sizes.h>
 #include <errno.h>
+#include <asm/arch/sys_proto.h>
 
 #define PCI_ACCESS_READ  0
 #define PCI_ACCESS_WRITE 1
@@ -430,6 +431,10 @@ static int imx_pcie_write_config(struct pci_controller *hose, pci_dev_t d,
 static int imx6_pcie_assert_core_reset(void)
 {
 	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
+
+	if (is_mx6dqp())
+		setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);
+
 #if defined(CONFIG_MX6SX)
 	struct gpc *gpc_regs = (struct gpc *)GPC_BASE_ADDR;
 
@@ -536,6 +541,9 @@ static int imx6_pcie_deassert_core_reset(void)
 
 	enable_pcie_clock();
 
+	if (is_mx6dqp())
+		clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);
+
 	/*
 	 * Wait for the clock to settle a bit, when the clock are sourced
 	 * from the CPU, we need about 30 ms to settle.