[U-Boot] [PATCH] pci: mx6: fix occasional link failures

[Fabio Estevam]

On Fri, Aug 8, 2014 at 10:33 AM, Marek Vasut <marex at denx.de> wrote:

> Can you guys test it on FSL hardware ?

Sure, I am running u-boot-imx with Tim's patch applied and this
additional debug patch that shows the number of reboots and PCI
linkups:

 drivers/pci/pcie_imx.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/pcie_imx.c b/drivers/pci/pcie_imx.c
index a3982c4..1ee77f9 100644
--- a/drivers/pci/pcie_imx.c
+++ b/drivers/pci/pcie_imx.c
@@ -20,6 +20,8 @@
 #include <linux/sizes.h>
 #include <errno.h>

+#define DEBUG
+
 #define PCI_ACCESS_READ  0
 #define PCI_ACCESS_WRITE 1

@@ -573,6 +575,10 @@ void imx_pcie_init(void)
     static struct pci_controller    pcc;
     struct pci_controller        *hose = &pcc;
     int ret;
+#ifdef DEBUG
+    u32 dbg_reg_addr = 0x020cc068;
+    u32 dbg_reg = readl(dbg_reg_addr) + 1;
+#endif

     memset(&pcc, 0, sizeof(pcc));

@@ -607,7 +613,14 @@ void imx_pcie_init(void)
     if (!ret) {
         pci_register_hose(hose);
         hose->last_busno = pci_hose_scan(hose);
+#ifdef DEBUG
+        dbg_reg += 1<<16;
+#endif
     }
+#ifdef DEBUG
+    writel(dbg_reg, dbg_reg_addr);
+    printf("PCIe Successes/Attempts: %d/%d\n", dbg_reg >> 16, dbg_reg
& 0xffff);
+#endif
 }

Then I do:

=> setenv bootcmd reset
=> save
=> reboot

,connect an Intel Wifi 7260HMW card to the mx6qsabresd and let the
system rebooting in loop.

It has been running with no PCI linkup failures here:

U-Boot 2014.07-16451-g7496820-dirty (Aug 08 2014 - 11:34:13)

CPU:   Freescale i.MX6Q rev1.1 at 792 MHz
Reset cause: WDOG
Board: MX6-SabreSD
I2C:   ready
DRAM:  1 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
  00:01.0     - 16c3:abcd - Bridge device
   01:00.0    - 8086:08b1 - Network controller
PCIe Successes/Attempts: 2350/2350
No panel detected: default to Hannstar-XGA
Display: Hannstar-XGA (1024x768)
In:    serial
Out:   serial
Err:   serial
PMIC:  PFUZE100 ID=0x10
Net:   FEC [PRIME]

So here goes my:

Tested-by: Fabio Estevam <fabio.estevam at freescale.com>

Regards,

Fabio Estevam