[PATCH 2/2] usb: dwc3: Add driver for Xilinx platforms
Felipe Balbi
balbi at kernel.org
Thu Aug 27 02:31:30 EDT 2020
Manish Narani <manish.narani at xilinx.com> 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
> 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 at xilinx.com>
> + * Manish Narani <manish.narani at 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
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