[03/10] usb: host: xhci-tegra: Avoid a fixed duration sleep
diff mbox series

Message ID 20191125123210.1564323-4-thierry.reding@gmail.com
State Changes Requested
Headers show
Series
  • usb: host: xhci-tegra: Implement basic ELPG support
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Commit Message

Thierry Reding Nov. 25, 2019, 12:32 p.m. UTC
From: Thierry Reding <treding@nvidia.com>

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@nvidia.com>.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/usb/host/xhci-tegra.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

Comments

Mikko Perttunen Nov. 25, 2019, 1:33 p.m. UTC | #1
On 25.11.2019 14.32, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> 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@nvidia.com>.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>   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);
> 

readx_poll_timeout? I think you can define a local macro to "curry" the 
'tegra' argument to csb_readl..

#define tegra_csb_readl(x) csb_readl(tegra, x)
readx_poll_timeout(tegra_csb_readl, ...)

Cheers,
Mikko

Patch
diff mbox series

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);