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Message-ID: <20250605003240.f66u3jf4r4ft2qtr@synopsys.com>
Date: Thu, 5 Jun 2025 00:32:44 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
CC: Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"michal.simek@....com" <michal.simek@....com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"git@....com" <git@....com>
Subject: Re: [PATCH] usb: dwc3: xilinx: set coherency mode for AMD versal
adaptive platform
On Wed, Jun 04, 2025, Radhey Shyam Pandey wrote:
> If device is coherent or if DMA (direct memory access) is translated by
> an IOMMU then program USB2.0 IP to route transactions through the CCI for
> coherency even if the target of transaction is in low power domain (LPD).
>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
> ---
> drivers/usb/dwc3/dwc3-xilinx.c | 34 ++++++++++++++++++++++------------
> 1 file changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
> index 4ca7f6240d07..00e613c4d8c0 100644
> --- a/drivers/usb/dwc3/dwc3-xilinx.c
> +++ b/drivers/usb/dwc3/dwc3-xilinx.c
> @@ -32,6 +32,9 @@
> #define XLNX_USB_TRAFFIC_ROUTE_CONFIG 0x005C
> #define XLNX_USB_TRAFFIC_ROUTE_FPD 0x1
>
> +/* USB 2.0 IP Register */
> +#define XLNX_USB2_TRAFFIC_ROUTE_CONFIG 0x0044
> +
> #define XLNX_USB_FPD_PIPE_CLK 0x7c
> #define PIPE_CLK_DESELECT 1
> #define PIPE_CLK_SELECT 0
> @@ -66,6 +69,23 @@ static void dwc3_xlnx_mask_phy_rst(struct dwc3_xlnx *priv_data, bool mask)
> writel(reg, priv_data->regs + XLNX_USB_PHY_RST_EN);
> }
>
> +static void dwc3_xlnx_set_coherency(struct dwc3_xlnx *priv_data, u32 coherency_offset)
> +{
> + struct device *dev = priv_data->dev;
> + u32 reg;
> +
> + /*
> + * This routes the USB DMA traffic to go through FPD path instead
> + * of reaching DDR directly. This traffic routing is needed to
> + * make SMMU and CCI work with USB DMA.
> + */
> + if (of_dma_is_coherent(dev->of_node) || device_iommu_mapped(dev)) {
> + reg = readl(priv_data->regs + coherency_offset);
> + reg |= XLNX_USB_TRAFFIC_ROUTE_FPD;
> + writel(reg, priv_data->regs + coherency_offset);
> + }
> +}
> +
> static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
> {
> struct device *dev = priv_data->dev;
> @@ -92,6 +112,7 @@ static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
> }
>
> dwc3_xlnx_mask_phy_rst(priv_data, true);
> + dwc3_xlnx_set_coherency(priv_data, XLNX_USB2_TRAFFIC_ROUTE_CONFIG);
>
> return 0;
> }
> @@ -102,7 +123,6 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
> struct reset_control *crst, *hibrst, *apbrst;
> struct gpio_desc *reset_gpio;
> int ret = 0;
> - u32 reg;
>
> priv_data->usb3_phy = devm_phy_optional_get(dev, "usb3-phy");
> if (IS_ERR(priv_data->usb3_phy)) {
> @@ -219,17 +239,7 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
> usleep_range(5000, 10000);
> }
>
> - /*
> - * This routes the USB DMA traffic to go through FPD path instead
> - * of reaching DDR directly. This traffic routing is needed to
> - * make SMMU and CCI work with USB DMA.
> - */
> - if (of_dma_is_coherent(dev->of_node) || device_iommu_mapped(dev)) {
> - reg = readl(priv_data->regs + XLNX_USB_TRAFFIC_ROUTE_CONFIG);
> - reg |= XLNX_USB_TRAFFIC_ROUTE_FPD;
> - writel(reg, priv_data->regs + XLNX_USB_TRAFFIC_ROUTE_CONFIG);
> - }
> -
> + dwc3_xlnx_set_coherency(priv_data, XLNX_USB_TRAFFIC_ROUTE_CONFIG);
> err:
> return ret;
> }
>
> base-commit: a0bea9e39035edc56a994630e6048c8a191a99d8
> --
> 2.34.1
>
Acked-by: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
BR,
Thinh
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