usb: dwc3: dwc3-am62: Re-initialize controller if lost power in PM suspend

If controller looses power during PM suspend then re-initialize
it. We use the DEBUG_CFG register to track if controller lost power
or was reset in PM suspend.

Move all initialization code into dwc3_ti_init() so it can be re-used.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20241212-am62-dwc3-io-ddr-v3-1-10b95cd7e9c0@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 5e3d1741701f7e871487e609066beadc022a59f4..a740d3d70e87940c8d9fa0e33951f3a4c9e1a4d2 100644 (file)
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -108,6 +108,9 @@
 
 #define DWC3_AM62_AUTOSUSPEND_DELAY    100
 
+#define USBSS_DEBUG_CFG_OFF            0x0
+#define USBSS_DEBUG_CFG_DISABLED       0x7
+
 struct dwc3_am62 {
        struct device *dev;
        void __iomem *usbss;
@@ -117,6 +120,7 @@ struct dwc3_am62 {
        unsigned int offset;
        unsigned int vbus_divider;
        u32 wakeup_stat;
+       void __iomem *phy_regs;
 };
 
 static const int dwc3_ti_rate_table[] = {      /* in KHZ */
@@ -184,15 +188,47 @@ static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
        return 0;
 }
 
+static int dwc3_ti_init(struct dwc3_am62 *am62)
+{
+       int ret;
+       u32 reg;
+
+       /* Read the syscon property and set the rate code */
+       ret = phy_syscon_pll_refclk(am62);
+       if (ret)
+               return ret;
+
+       /* Workaround Errata i2409 */
+       if (am62->phy_regs) {
+               reg = readl(am62->phy_regs + USB_PHY_PLL_REG12);
+               reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
+               writel(reg, am62->phy_regs + USB_PHY_PLL_REG12);
+       }
+
+       /* VBUS divider select */
+       reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);
+       if (am62->vbus_divider)
+               reg |= 1 << USBSS_PHY_VBUS_SEL_SHIFT;
+
+       dwc3_ti_writel(am62, USBSS_PHY_CONFIG, reg);
+
+       clk_prepare_enable(am62->usb2_refclk);
+
+       /* Set mode valid bit to indicate role is valid */
+       reg = dwc3_ti_readl(am62, USBSS_MODE_CONTROL);
+       reg |= USBSS_MODE_VALID;
+       dwc3_ti_writel(am62, USBSS_MODE_CONTROL, reg);
+
+       return 0;
+}
+
 static int dwc3_ti_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
        struct device_node *node = pdev->dev.of_node;
        struct dwc3_am62 *am62;
        unsigned long rate;
-       void __iomem *phy;
        int i, ret;
-       u32 reg;
 
        am62 = devm_kzalloc(dev, sizeof(*am62), GFP_KERNEL);
        if (!am62)
@@ -228,29 +264,17 @@ static int dwc3_ti_probe(struct platform_device *pdev)
 
        am62->rate_code = i;
 
-       /* Read the syscon property and set the rate code */
-       ret = phy_syscon_pll_refclk(am62);
-       if (ret)
-               return ret;
-
-       /* Workaround Errata i2409 */
-       phy = devm_platform_ioremap_resource(pdev, 1);
-       if (IS_ERR(phy)) {
+       am62->phy_regs = devm_platform_ioremap_resource(pdev, 1);
+       if (IS_ERR(am62->phy_regs)) {
                dev_err(dev, "can't map PHY IOMEM resource. Won't apply i2409 fix.\n");
-               phy = NULL;
-       } else {
-               reg = readl(phy + USB_PHY_PLL_REG12);
-               reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
-               writel(reg, phy + USB_PHY_PLL_REG12);
+               am62->phy_regs = NULL;
        }
 
-       /* VBUS divider select */
        am62->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
-       reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);
-       if (am62->vbus_divider)
-               reg |= 1 << USBSS_PHY_VBUS_SEL_SHIFT;
 
-       dwc3_ti_writel(am62, USBSS_PHY_CONFIG, reg);
+       ret = dwc3_ti_init(am62);
+       if (ret)
+               return ret;
 
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);
@@ -258,7 +282,6 @@ static int dwc3_ti_probe(struct platform_device *pdev)
         * Don't ignore its dependencies with its children
         */
        pm_suspend_ignore_children(dev, false);
-       clk_prepare_enable(am62->usb2_refclk);
        pm_runtime_get_noresume(dev);
 
        ret = of_platform_populate(node, NULL, NULL, dev);
@@ -267,11 +290,6 @@ static int dwc3_ti_probe(struct platform_device *pdev)
                goto err_pm_disable;
        }
 
-       /* Set mode valid bit to indicate role is valid */
-       reg = dwc3_ti_readl(am62, USBSS_MODE_CONTROL);
-       reg |= USBSS_MODE_VALID;
-       dwc3_ti_writel(am62, USBSS_MODE_CONTROL, reg);
-
        /* Device has capability to wakeup system from sleep */
        device_set_wakeup_capable(dev, true);
        ret = device_wakeup_enable(dev);
@@ -338,6 +356,9 @@ static int dwc3_ti_suspend_common(struct device *dev)
                dwc3_ti_writel(am62, USBSS_WAKEUP_STAT, USBSS_WAKEUP_STAT_CLR);
        }
 
+       /* just to track if module resets on suspend */
+       dwc3_ti_writel(am62, USBSS_DEBUG_CFG, USBSS_DEBUG_CFG_DISABLED);
+
        clk_disable_unprepare(am62->usb2_refclk);
 
        return 0;
@@ -348,7 +369,14 @@ static int dwc3_ti_resume_common(struct device *dev)
        struct dwc3_am62 *am62 = dev_get_drvdata(dev);
        u32 reg;
 
-       clk_prepare_enable(am62->usb2_refclk);
+       reg = dwc3_ti_readl(am62, USBSS_DEBUG_CFG);
+       if (reg != USBSS_DEBUG_CFG_DISABLED) {
+               /* lost power/context */
+               dwc3_ti_init(am62);
+       } else {
+               dwc3_ti_writel(am62, USBSS_DEBUG_CFG, USBSS_DEBUG_CFG_OFF);
+               clk_prepare_enable(am62->usb2_refclk);
+       }
 
        if (device_may_wakeup(dev)) {
                /* Clear wakeup config enable bits */