usb: langwell_udc: Init SRAM on S0i3 resume

On an exit from S0i3, the USB stack tries to access the SRAM
without initializing. Add SRAM initialization code to avoid
ECC error. This patch is for langwell_udc controller driver.

Change-Id: I92c80eed95094706020b8659a3db6585bdd8fca3
Signed-off-by: Sundar Iyer <sundar.iyer@intel.com>
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>

diff --git a/drivers/usb/gadget/langwell_udc.c b/drivers/usb/gadget/langwell_udc.c
index 262d120..5e2e575 100644 (file)
--- a/drivers/usb/gadget/langwell_udc.c
+++ b/drivers/usb/gadget/langwell_udc.c
@@ -2968,6 +2968,8 @@ static void gadget_release(struct device *_dev)
 static void sram_init(struct langwell_udc *dev)
 {
        struct pci_dev          *pdev = dev->pdev;
+       void __iomem            *base = NULL;
+       void __iomem            *addr = NULL;
 
        dev_dbg(&dev->pdev->dev, "---> %s()\n", __func__);
 
@@ -2975,6 +2977,23 @@ static void sram_init(struct langwell_udc *dev)
        dev->sram_size = pci_resource_len(pdev, 1);
        dev_info(&dev->pdev->dev, "Found private SRAM at %x size:%x\n",
                        dev->sram_addr, dev->sram_size);
+
+       /* initialize SRAM to 0 to avoid ECC errors */
+       base = ioremap_nocache(dev->sram_addr, dev->sram_size);
+       if (base == NULL) {
+               dev_err(&dev->pdev->dev, "SRAM init: ioremap failed\n");
+               return;
+       }
+
+       addr = base;
+
+       while (addr < base + dev->sram_size) {
+               writel(0x0, addr);
+               addr = addr + 4;
+       }
+
+       iounmap(base);
+
        dev->got_sram = 1;
 
        if (pci_request_region(pdev, 1, kobject_name(&pdev->dev.kobj))) {