From: Thierry Reding <treding@xxxxxxxxxx>
Do not use a fixed duration sleep to wait for the DMA controller to
become ready. Instead, poll the L2IMEMOP_RESULT register for the VLD
flag to determine when the XUSB controller's DMA master is ready.
Based on work by JC Kuo <jckuo@xxxxxxxxxx>.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/usb/host/xhci-tegra.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 5cfd54862670..d15fd16168ae 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -101,6 +101,8 @@
#define L2IMEMOP_ACTION_SHIFT 24
#define L2IMEMOP_INVALIDATE_ALL (0x40 << L2IMEMOP_ACTION_SHIFT)
#define L2IMEMOP_LOAD_LOCKED_RESULT (0x11 << L2IMEMOP_ACTION_SHIFT)
+#define XUSB_CSB_MEMPOOL_L2IMEMOP_RESULT 0x101a18
+#define L2IMEMOP_RESULT_VLD BIT(31)
#define XUSB_CSB_MP_APMAP 0x10181c
#define APMAP_BOOTPATH BIT(31)
@@ -893,7 +895,22 @@ static int tegra_xusb_load_firmware(struct tegra_xusb *tegra)
csb_writel(tegra, 0, XUSB_FALC_DMACTL);
- msleep(50);
+ /* wait for RESULT_VLD to get set */
+ timeout = jiffies + msecs_to_jiffies(10);
+
+ do {
+ value = csb_readl(tegra, XUSB_CSB_MEMPOOL_L2IMEMOP_RESULT);
+ if (value & L2IMEMOP_RESULT_VLD)
+ break;
+
+ usleep_range(50, 100);
+ } while (time_is_after_jiffies(timeout));
+
+ value = csb_readl(tegra, XUSB_CSB_MEMPOOL_L2IMEMOP_RESULT);
+ if ((value & L2IMEMOP_RESULT_VLD) == 0) {
+ dev_err(dev, "DMA controller not ready %#010x\n", value);
+ return -EBUSY;
+ }
csb_writel(tegra, le32_to_cpu(header->boot_codetag),
XUSB_FALC_BOOTVEC);
--
2.23.0
