[PATCH v2 3/4] usb: ehci: Add new EHCI driver for Broadcom STB SoC's

Al Cooper
2020-03-27T20:47:48Z

Add a new EHCI driver for Broadcom STB SoC's. A new EHCI driver
was created instead of adding support to the existing ehci platform
driver because of the code required to workaround bugs in the EHCI
controller.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
---
drivers/usb/host/ehci-brcm.c | 290 +++++++++++++++++++++++++++++++++++
1 file changed, 290 insertions(+)
create mode 100644 drivers/usb/host/ehci-brcm.c

diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c
new file mode 100644
index 000000000000..af75f3267d01
--- /dev/null
+++ b/drivers/usb/host/ehci-brcm.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018, Broadcom */
+
+#include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/iopoll.h>
+
+#include "ehci.h"
+
+#define BRCM_DRIVER_DESC "EHCI Broadcom STB driver"
+
+#define hcd_to_ehci_priv(h) ((struct brcm_priv *)hcd_to_ehci(h)->priv)
+
+struct brcm_priv {
+ struct clk *clk;
+};
+
+static const char brcm_hcd_name[] = "ehci-brcm";
+
+static int (*org_hub_control)(struct usb_hcd *hcd,
+ u16 typeReq, u16 wValue, u16 wIndex,
+ char *buf, u16 wLength);
+
+/*
+ * ehci_brcm_wait_for_sof
+ * Wait for start of next microframe, then wait extra delay microseconds
+ */
+static inline void ehci_brcm_wait_for_sof(struct ehci_hcd *ehci, u32 delay)
+{
+ u32 frame_idx = ehci_readl(ehci, &ehci->regs->frame_index);
+ u32 val;
+ int res;
+
+ /* Wait for next microframe (every 125 usecs) */
+ res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,
+ (val != frame_idx), 1, 130);
+ if (res)
+ dev_err(ehci_to_hcd(ehci)->self.controller,
+ "Error waiting for SOF\n");
+ udelay(delay);
+}
+
+/*
+ * ehci_brcm_hub_control
+ * Intercept echi-hcd request to complete RESUME and align it to the start
+ * of the next microframe.
+ * If RESUME is complete too late in the microframe, host controller
+ * detects babble on suspended port and resets the port afterwards.
+ * This s/w workaround allows to avoid this problem.
+ * See SWLINUX-1909 for more details
+ */
+static int ehci_brcm_hub_control(
+ struct usb_hcd *hcd,
+ u16 typeReq,
+ u16 wValue,
+ u16 wIndex,
+ char *buf,
+ u16 wLength)
+{
+ struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ int ports = HCS_N_PORTS(ehci->hcs_params);
+ u32 __iomem *status_reg = &ehci->regs->port_status[
+ (wIndex & 0xff) - 1];
+ unsigned long flags;
+ int retval, irq_disabled = 0;
+
+ /*
+ * RESUME is cleared when GetPortStatus() is called 20ms after start
+ * of RESUME
+ */
+ if ((typeReq == GetPortStatus) &&
+ (wIndex && wIndex <= ports) &&
+ ehci->reset_done[wIndex-1] &&
+ time_after_eq(jiffies, ehci->reset_done[wIndex-1]) &&
+ (ehci_readl(ehci, status_reg) & PORT_RESUME)) {
+
+ /*
+ * to make sure we are not interrupted until RESUME bit
+ * is cleared, disable interrupts on current CPU
+ */
+ ehci_dbg(ehci, "SOF alignment workaround\n");
+ irq_disabled = 1;
+ local_irq_save(flags);
+ ehci_brcm_wait_for_sof(ehci, 5);
+ }
+ retval = (*org_hub_control)(hcd, typeReq, wValue, wIndex, buf, wLength);
+ if (irq_disabled)
+ local_irq_restore(flags);
+ return retval;
+}
+
+static int ehci_brcm_reset(struct usb_hcd *hcd)
+{
+ struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+
+ ehci->big_endian_mmio = 1;
+
+ ehci->caps = (struct ehci_caps *) hcd->regs;
+ ehci->regs = (struct ehci_regs *) (hcd->regs +
+ HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase)));
+
+ /* This fixes the lockup during reboot due to prior interrupts */
+ ehci_writel(ehci, CMD_RESET, &ehci->regs->command);
+ mdelay(10);
+
+ /*
+ * SWLINUX-1705: Avoid OUT packet underflows during high memory
+ * bus usage
+ * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90
+ */
+ ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);
+ ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);
+
+ return ehci_setup(hcd);
+}
+
+static struct hc_driver __read_mostly ehci_brcm_hc_driver;
+
+static const struct ehci_driver_overrides brcm_overrides __initconst = {
+
+ .reset = ehci_brcm_reset,
+ .extra_priv_size = sizeof(struct brcm_priv),
+};
+
+static int ehci_brcm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res_mem;
+ struct brcm_priv *priv;
+ struct usb_hcd *hcd;
+ int irq;
+ int err;
+
+ if (usb_disabled())
+ return -ENODEV;
+
+ err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+ if (err)
+ return err;
+
+ irq = platform_get_irq(pdev, 0);
+ return irq;
+
+ /* Hook the hub control routine to work around a bug */
+ if (org_hub_control == NULL)
+ org_hub_control = ehci_brcm_hc_driver.hub_control;
+ ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;
+
+ /* initialize hcd */
+ hcd = usb_create_hcd(&ehci_brcm_hc_driver, dev, dev_name(dev));
+ if (!hcd)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, hcd);
+ priv = hcd_to_ehci_priv(hcd);
+
+ priv->clk = devm_clk_get_optional(dev, NULL);
+ if (IS_ERR(priv->clk)) {
+ err = PTR_ERR(priv->clk);
+ goto err_hcd;
+ }
+
+ err = clk_prepare_enable(priv->clk);
+ if (err)
+ goto err_hcd;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ hcd->regs = devm_ioremap_resource(dev, res_mem);
+ if (IS_ERR(hcd->regs)) {
+ err = PTR_ERR(hcd->regs);
+ goto err_clk;
+ }
+ hcd->rsrc_start = res_mem->start;
+ hcd->rsrc_len = resource_size(res_mem);
+ err = usb_add_hcd(hcd, irq, IRQF_SHARED);
+ if (err)
+ goto err_clk;
+
+ device_wakeup_enable(hcd->self.controller);
+ device_enable_async_suspend(hcd->self.controller);
+ platform_set_drvdata(pdev, hcd);
+
+ return err;
+
+err_clk:
+ clk_disable_unprepare(priv->clk);
+err_hcd:
+ usb_put_hcd(hcd);
+
+ return err;
+}
+
+static int ehci_brcm_remove(struct platform_device *dev)
+{
+ struct usb_hcd *hcd = platform_get_drvdata(dev);
+ struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
+
+ usb_remove_hcd(hcd);
+ clk_disable_unprepare(priv->clk);
+ usb_put_hcd(hcd);
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int ehci_brcm_suspend(struct device *dev)
+{
+ int ret;
+ struct usb_hcd *hcd = dev_get_drvdata(dev);
+ struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
+ bool do_wakeup = device_may_wakeup(dev);
+
+ ret = ehci_suspend(hcd, do_wakeup);
+ clk_disable_unprepare(priv->clk);
+ return ret;
+}
+
+static int ehci_brcm_resume(struct device *dev)
+{
+ struct usb_hcd *hcd = dev_get_drvdata(dev);
+ struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
+ int err;
+
+ err = clk_prepare_enable(priv->clk);
+ if (err)
+ return err;
+ /*
+ * SWLINUX-1705: Avoid OUT packet underflows during high memory
+ * bus usage
+ * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00
+ * @ 0x90
+ */
+ ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);
+ ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);
+
+ ehci_resume(hcd, false);
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(ehci_brcm_pm_ops, ehci_brcm_suspend,
+ ehci_brcm_resume);
+
+static const struct of_device_id brcm_ehci_of_match[] = {
+ { .compatible = "brcm,ehci-brcm-v2", },
+ { .compatible = "brcm,bcm7445-ehci", },
+ {}
+};
+
+static struct platform_driver ehci_brcm_driver = {
+ .probe = ehci_brcm_probe,
+ .remove = ehci_brcm_remove,
+ .shutdown = usb_hcd_platform_shutdown,
+ .driver = {
+ .name = "ehci-brcm",
+ .pm = &ehci_brcm_pm_ops,
+ .of_match_table = brcm_ehci_of_match,
+ }
+};
+
+static int __init ehci_brcm_init(void)
+{
+ if (usb_disabled())
+ return -ENODEV;
+
+ ehci_init_driver(&ehci_brcm_hc_driver, &brcm_overrides);
+ return platform_driver_register(&ehci_brcm_driver);
+}
+module_init(ehci_brcm_init);
+
+static void __exit ehci_brcm_exit(void)
+{
+ platform_driver_unregister(&ehci_brcm_driver);
+}
+module_exit(ehci_brcm_exit);
+
+MODULE_ALIAS("platform:ehci-brcm");
+MODULE_DESCRIPTION(BRCM_DRIVER_DESC);
+MODULE_AUTHOR("Al Cooper");
+MODULE_LICENSE("GPL");
--
2.17.1