Re: [PATCH 2/2] usb: dwc3: Add driver for Xilinx platforms
From: Felipe Balbi <balbi@kernel.org>
Date: 2020-08-27 06:31:49
Also in:
linux-devicetree, linux-usb, lkml
Manish Narani [off-list ref] writes:
Add a new driver for supporting Xilinx platforms. This driver handles the USB 3.0 PHY initialization and PIPE control & reset operations for
PHY initialization should be done as part of a drivers/phy driver.
ZynqMP platforms. This also handles the USB 2.0 PHY initialization and reset operations for Versal platforms.
similarly for USB2 PHYs
quoted hunk ↗ jump to hunk
diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c new file mode 100644 index 000000000000..272906797a7a --- /dev/null +++ b/drivers/usb/dwc3/dwc3-xilinx.c@@ -0,0 +1,416 @@ +// SPDX-License-Identifier: GPL-2.0 +/** + * dwc3-xilinx.c - Xilinx DWC3 controller specific glue driver + * + * Authors: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com> + * Manish Narani <manish.narani@xilinx.com> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/clk.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/dma-mapping.h> +#include <linux/of_platform.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/of_address.h> +#include <linux/delay.h> +#include <linux/firmware/xlnx-zynqmp.h> +#include <linux/io.h> + +#include <linux/phy/phy.h> + +/* USB phy reset mask register */ +#define XLNX_USB_PHY_RST 0x001C +#define XLNX_PHY_RST_MASK 0x1 + +/* Xilinx USB 3.0 IP Register */ +#define XLNX_USB_COHERENCY 0x005C +#define XLNX_USB_COHERENCY_ENABLE 0x1 + +/* Versal USB Reset ID */ +#define VERSAL_USB_RESET_ID 0xC104036 + +#define PIPE_CLK_OFFSET 0x7c +#define PIPE_CLK_ON 1 +#define PIPE_CLK_OFF 0 +#define PIPE_POWER_OFFSET 0x80 +#define PIPE_POWER_ON 1 +#define PIPE_POWER_OFF 0 + +#define RST_TIMEOUT 1000 + +struct dwc3_xlnx { + int num_clocks; + struct clk_bulk_data *clks; + struct device *dev; + void __iomem *regs; + struct dwc3 *dwc; + struct phy *phy; + struct phy *usb3_phy; + struct reset_control *crst; + struct reset_control *hibrst; + struct reset_control *apbrst; +}; + +static void dwc3_xlnx_mask_phy_rst(struct dwc3_xlnx *priv_data, bool mask) +{ + u32 reg; + + reg = readl(priv_data->regs + XLNX_USB_PHY_RST); + + if (mask) + /* + * Mask the phy reset signal from comtroller
s/comtroller/controller But really, the comments don't bring any extra information. I'd say remove the comments as the code speaks for itself very clearly in this case.
+static int dwc3_xlnx_rst_assert(struct reset_control *rstc)
this looks like it should be an actual 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");
+ if (IS_ERR(priv_data->crst)) {
+ dev_err(dev, "failed to get %s reset signal\n", "usb_crst");
+ 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;
+ }
+
+ 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__);you don't need the function name or the line number here. Just improve your error message a bit: dev_err(dev, "Failed to assert usb3-phy reset\n");
+ 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__);dev_err(dev, "Failed to assert hibernation reset\n");
+ 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__);dev_err(dev, "Failed to assert APB reset\n");
+ goto err; + } + + ret = phy_init(priv_data->usb3_phy);
dwc3 core should be handling this already
+ 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);shouldn't this be hidden under clk_enable()?
+ 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;
+ }you don't need to check res here. devm_ioremap_resource() already does that for you.
+ regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(regs)) + return PTR_ERR(regs);
this looks like it could use an error message.
+ /* Store the usb control regs into priv_data for further usage */
pointless comment.
+ priv_data->regs = regs; +
unnecessary blank line.
+ priv_data->dev = dev;
+
+ platform_set_drvdata(pdev, priv_data);
+
+ ret = clk_bulk_get_all(priv_data->dev, &priv_data->clks);
+ if (ret < 0)
+ return ret;
+
+ priv_data->num_clocks = ret;
+
+ ret = clk_bulk_prepare_enable(priv_data->num_clocks, priv_data->clks);
+ if (ret)
+ return ret;
+
+ if (of_device_is_compatible(pdev->dev.of_node, "xlnx,zynqmp-dwc3")) {
+ ret = dwc3_xlnx_init_zynqmp(priv_data);
+ if (ret)
+ goto err_clk_put;
+ }instead, you could pass a pointer to dwc3_xlnx_init_zynqmp() as driver data and just call it unconditionally. It would avoid the compatible check here.
+ if (of_device_is_compatible(pdev->dev.of_node, "xlnx,versal-dwc3")) {
+ ret = dwc3_xlnx_init_versal(priv_data);
+ if (ret)
+ goto err_clk_put;
+ }same as above
+ ret = of_platform_populate(np, NULL, NULL, dev); + if (ret) + goto err_clk_put; + + pm_runtime_set_active(dev); + pm_runtime_enable(dev); + pm_suspend_ignore_children(dev, false); + pm_runtime_get_sync(dev); + + pm_runtime_forbid(dev);
why forbid? You already have a get_sync()
+ return 0;
+
+err_clk_put:
+ clk_bulk_disable_unprepare(priv_data->num_clocks, priv_data->clks);
+ clk_bulk_put_all(priv_data->num_clocks, priv_data->clks);
+
+ return ret;
+}
+
+static int dwc3_xlnx_remove(struct platform_device *pdev)
+{
+ struct dwc3_xlnx *priv_data = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ of_platform_depopulate(dev);
+
+ clk_bulk_disable_unprepare(priv_data->num_clocks, priv_data->clks);
+ clk_bulk_put_all(priv_data->num_clocks, priv_data->clks);
+ priv_data->num_clocks = 0;
+
+ pm_runtime_disable(dev);
+ pm_runtime_put_noidle(dev);
+ pm_runtime_set_suspended(dev);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int dwc3_xlnx_runtime_suspend(struct device *dev)
+{
+ struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
+
+ clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
+
+ return 0;
+}
+
+static int dwc3_xlnx_runtime_idle(struct device *dev)
+{
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_autosuspend(dev);
+
+ return 0;
+}
+
+static int dwc3_xlnx_runtime_resume(struct device *dev)
+{
+ struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
+
+ return clk_bulk_enable(priv_data->num_clocks, priv_data->clks);
+}
+#endif /* CONFIG_PM */
+
+#ifdef CONFIG_PM_SLEEP
+static int dwc3_xlnx_suspend(struct device *dev)
+{
+ struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
+
+ /* Disable the clocks */
+ clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
+
+ return 0;
+}
+
+static int dwc3_xlnx_resume(struct device *dev)
+{
+ struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
+
+ return clk_bulk_enable(priv_data->num_clocks, priv_data->clks);
+}
you have the same implementation for both types of suspend/resume. Maybe
extract dwc3_xlnx_{suspend,resume}_common() and just call it from both
callbacks?
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops dwc3_xlnx_dev_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(dwc3_xlnx_suspend, dwc3_xlnx_resume)
+ SET_RUNTIME_PM_OPS(dwc3_xlnx_runtime_suspend, dwc3_xlnx_runtime_resume,
+ dwc3_xlnx_runtime_idle)seems like it could be replaced with UNIVERSAL_PM_OPS with minor modifications. -- balbi