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Message-ID: <8d3045b22bf9524eba9dddf1ff470858d4b748be.camel@pengutronix.de>
Date: Thu, 27 Aug 2020 11:02:58 +0200
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Manish Narani <manish.narani@...inx.com>,
gregkh@...uxfoundation.org, robh+dt@...nel.org,
michal.simek@...inx.com, balbi@...nel.org
Cc: linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
git@...inx.com
Subject: Re: [PATCH 2/2] usb: dwc3: Add driver for Xilinx platforms
Hi Manish,
On Thu, 2020-08-27 at 00:14 +0530, Manish Narani wrote:
> Add a new driver for supporting Xilinx platforms. This driver handles
> the USB 3.0 PHY initialization and PIPE control & reset operations for
> ZynqMP platforms. This also handles the USB 2.0 PHY initialization and
> reset operations for Versal platforms.
>
> Signed-off-by: Manish Narani <manish.narani@...inx.com>
> ---
[...]
> +static int dwc3_xlnx_rst_assert(struct reset_control *rstc)
> +{
> + unsigned long loop_time = msecs_to_jiffies(RST_TIMEOUT);
> + unsigned long timeout;
> +
> + reset_control_assert(rstc);
> +
> + /* wait until reset is asserted or timeout */
> + timeout = jiffies + loop_time;
> +
> + while (!time_after_eq(jiffies, timeout)) {
> + if (reset_control_status(rstc) > 0)
> + return 0;
> +
> + cpu_relax();
> + }
> +
> + return -ETIMEDOUT;
> +}
I think this should be done in the reset controller driver instead.
When reset_control_assert() is called with an exclusive reset control,
the reset line should be already asserted when the function returns.
> +
> +static int dwc3_xlnx_rst_deassert(struct reset_control *rstc)
> +{
> + unsigned long loop_time = msecs_to_jiffies(RST_TIMEOUT);
> + unsigned long timeout;
> +
> + reset_control_deassert(rstc);
> +
> + /* wait until reset is de-asserted or timeout */
> + timeout = jiffies + loop_time;
> + while (!time_after_eq(jiffies, timeout)) {
> + if (!reset_control_status(rstc))
> + return 0;
> +
> + cpu_relax();
> + }
> +
> + return -ETIMEDOUT;
> +}
Same as above, this belongs in the reset controller driver.
> +static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
> +{
> + struct device *dev = priv_data->dev;
> + int ret;
> +
> + dwc3_xlnx_mask_phy_rst(priv_data, false);
> +
> + /* Assert and De-assert reset */
> + ret = zynqmp_pm_reset_assert(VERSAL_USB_RESET_ID,
> + PM_RESET_ACTION_ASSERT);
> + if (ret < 0) {
> + dev_err(dev, "failed to assert Reset\n");
> + return ret;
> + }
> +
> + ret = zynqmp_pm_reset_assert(VERSAL_USB_RESET_ID,
> + PM_RESET_ACTION_RELEASE);
> + if (ret < 0) {
> + dev_err(dev, "failed to De-assert Reset\n");
> + return ret;
> + }
> +
> + dwc3_xlnx_mask_phy_rst(priv_data, true);
> +
> + return 0;
> +}
> +
> +static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
> +{
> + struct device *dev = priv_data->dev;
> + int ret;
> + u32 reg;
> +
> + priv_data->crst = devm_reset_control_get(dev, "usb_crst");
Please use devm_reset_control_get_exclusive() instead.
> + if (IS_ERR(priv_data->crst)) {
> + dev_err(dev, "failed to get %s reset signal\n", "usb_crst");
Consider using dev_err_probe() to hide -EPROBE_DEFER error values.
> + ret = PTR_ERR(priv_data->crst);
> + goto err;
> + }
> +
> + priv_data->hibrst = devm_reset_control_get(dev, "usb_hibrst");
> + if (IS_ERR(priv_data->hibrst)) {
> + dev_err(dev, "failed to get %s reset signal\n", "usb_hibrst");
> + ret = PTR_ERR(priv_data->hibrst);
> + goto err;
> + }
> +
> + priv_data->apbrst = devm_reset_control_get(dev, "usb_apbrst");
> + if (IS_ERR(priv_data->apbrst)) {
> + dev_err(dev, "failed to get %s reset signal\n", "usb_apbrst");
> + ret = PTR_ERR(priv_data->apbrst);
> + goto err;
> + }
Same as above for the other two reset controls.
> + priv_data->usb3_phy = devm_phy_get(dev, "usb3-phy");
> +
> + ret = dwc3_xlnx_rst_assert(priv_data->crst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to assert reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + ret = dwc3_xlnx_rst_assert(priv_data->hibrst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to assert reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + ret = dwc3_xlnx_rst_assert(priv_data->apbrst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to assert reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + ret = phy_init(priv_data->usb3_phy);
> + if (ret < 0) {
> + phy_exit(priv_data->usb3_phy);
> + goto err;
> + }
> +
> + ret = dwc3_xlnx_rst_deassert(priv_data->apbrst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to release reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + /* Set PIPE power present signal */
> + writel(PIPE_POWER_ON, priv_data->regs + PIPE_POWER_OFFSET);
> +
> + /* Clear PIPE CLK signal */
> + writel(PIPE_CLK_OFF, priv_data->regs + PIPE_CLK_OFFSET);
> +
> + ret = dwc3_xlnx_rst_deassert(priv_data->crst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to release reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + ret = dwc3_xlnx_rst_deassert(priv_data->hibrst);
> + if (ret < 0) {
> + dev_err(dev, "%s: %d: Failed to release reset\n",
> + __func__, __LINE__);
> + goto err;
> + }
> +
> + ret = phy_power_on(priv_data->usb3_phy);
> + if (ret < 0) {
> + phy_exit(priv_data->usb3_phy);
> + goto err;
> + }
> +
> + /*
> + * This routes the usb dma traffic to go through CCI 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) || dev->iommu_group) {
> + reg = readl(priv_data->regs + XLNX_USB_COHERENCY);
> + reg |= XLNX_USB_COHERENCY_ENABLE;
> + writel(reg, priv_data->regs + XLNX_USB_COHERENCY);
> + }
> +
> +err:
> + return ret;
> +}
> +
> +static int dwc3_xlnx_probe(struct platform_device *pdev)
> +{
> + struct dwc3_xlnx *priv_data;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct resource *res;
> + void __iomem *regs;
> + int ret;
> +
> + priv_data = devm_kzalloc(dev, sizeof(*priv_data), GFP_KERNEL);
> + if (!priv_data)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(dev, "missing memory resource\n");
> + return -ENODEV;
> + }
> +
> + regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +
> + /* Store the usb control regs into priv_data for further usage */
> + priv_data->regs = regs;
> +
> + priv_data->dev = dev;
> +
> + platform_set_drvdata(pdev, priv_data);
> +
> + ret = clk_bulk_get_all(priv_data->dev, &priv_data->clks);
Why not use devm_clk_bulk_get_all()?
regards
Philipp
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