usb: host: xhci-tegra: Use CNR as firmware ready indicator

The Falcon CPU state is a suboptimal indicator for firmware readiness,
since the Falcon can be in a running state if the firmware is handling
port state changes or running other tasks. Instead, the driver should
check the STS_CNR bit to determine whether or not the firmware has been
successfully loaded and is ready for XHCI operation.

Based on work by JC Kuo <jckuo@nvidia.com>.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20191206140653.2085561-5-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index e80fce712fd507de37897c9c33a71ff254e8c085..eda5e1d50828ca8c9a46a45130156778f429aedc 100644 (file)
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -830,10 +830,10 @@ static int tegra_xusb_request_firmware(struct tegra_xusb *tegra)
 static int tegra_xusb_load_firmware(struct tegra_xusb *tegra)
 {
        unsigned int code_tag_blocks, code_size_blocks, code_blocks;
+       struct xhci_cap_regs __iomem *cap = tegra->regs;
        struct tegra_xusb_fw_header *header;
-       struct xhci_cap_regs __iomem *cap;
-       struct xhci_op_regs __iomem *op;
        struct device *dev = tegra->dev;
+       struct xhci_op_regs __iomem *op;
        unsigned long timeout;
        time64_t timestamp;
        struct tm time;
@@ -842,6 +842,7 @@ static int tegra_xusb_load_firmware(struct tegra_xusb *tegra)
        int err;
 
        header = (struct tegra_xusb_fw_header *)tegra->fw.virt;
+       op = tegra->regs + HC_LENGTH(readl(&cap->hc_capbase));
 
        if (csb_readl(tegra, XUSB_CSB_MP_ILOAD_BASE_LO) != 0) {
                dev_info(dev, "Firmware already loaded, Falcon state %#x\n",
@@ -911,21 +912,23 @@ static int tegra_xusb_load_firmware(struct tegra_xusb *tegra)
        csb_writel(tegra, le32_to_cpu(header->boot_codetag),
                   XUSB_FALC_BOOTVEC);
 
-       /* Boot Falcon CPU and wait for it to enter the STOPPED (idle) state. */
-       timeout = jiffies + msecs_to_jiffies(5);
-
+       /* Boot Falcon CPU and wait for USBSTS_CNR to get cleared. */
        csb_writel(tegra, CPUCTL_STARTCPU, XUSB_FALC_CPUCTL);
 
-       while (time_before(jiffies, timeout)) {
-               if (csb_readl(tegra, XUSB_FALC_CPUCTL) == CPUCTL_STATE_STOPPED)
+       timeout = jiffies + msecs_to_jiffies(200);
+
+       do {
+               value = readl(&op->status);
+               if ((value & STS_CNR) == 0)
                        break;
 
-               usleep_range(100, 200);
-       }
+               usleep_range(1000, 2000);
+       } while (time_is_after_jiffies(timeout));
 
-       if (csb_readl(tegra, XUSB_FALC_CPUCTL) != CPUCTL_STATE_STOPPED) {
-               dev_err(dev, "Falcon failed to start, state: %#x\n",
-                       csb_readl(tegra, XUSB_FALC_CPUCTL));
+       value = readl(&op->status);
+       if (value & STS_CNR) {
+               value = csb_readl(tegra, XUSB_FALC_CPUCTL);
+               dev_err(dev, "XHCI controller not read: %#010x\n", value);
                return -EIO;
        }