diff mbox series

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

Message ID 20200327204711.10614-4-alcooperx@gmail.com (mailing list archive)
State Superseded
Headers show
Series Add XHCI, EHCI and OHCI support for Broadcom STB SoS's | expand

Commit Message

Alan Cooper March 27, 2020, 8:47 p.m. UTC
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

Comments

Alan Stern March 28, 2020, 12:38 a.m. UTC | #1
On Fri, 27 Mar 2020, Al Cooper wrote:

> 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>
> ---

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Andy Shevchenko March 28, 2020, 8:18 p.m. UTC | #2
On Fri, Mar 27, 2020 at 04:47:10PM -0400, Al Cooper wrote:
> 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.

I'm not sure this has been tested. See below.

...

> +#include <linux/acpi.h>
> +#include <linux/of.h>

I didn;t find evidence these are needed.

...


> +	res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,
> +					 (val != frame_idx), 1, 130);

Too many parentheses.

> +	if (res)
> +		dev_err(ehci_to_hcd(ehci)->self.controller,
> +			"Error waiting for SOF\n");

...

> +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;

I'm not sure it was an intention to leave a lot of dead code below.

> +	/* Hook the hub control routine to work around a bug */

> +	if (org_hub_control == NULL)

	if (!org_hub_control) ?

> +		org_hub_control = ehci_brcm_hc_driver.hub_control;
> +	ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;

> +	device_wakeup_enable(hcd->self.controller);
> +	device_enable_async_suspend(hcd->self.controller);
> +	platform_set_drvdata(pdev, hcd);
> +

> +	return err;

	return 0; ?

> +err_clk:
> +	clk_disable_unprepare(priv->clk);
> +err_hcd:
> +	usb_put_hcd(hcd);
> +
> +	return err;
> +}

...

> +#ifdef CONFIG_PM_SLEEP

You also can use __maybe_unused annotations.

> +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;

So, if you fail to suspend the device, clocks will become unusable, how to recover from such case?

> +}

> +#endif /* CONFIG_PM_SLEEP */

...

> +MODULE_DESCRIPTION(BRCM_DRIVER_DESC);

Better to have it explicit.
Alan Cooper April 6, 2020, 6:46 p.m. UTC | #3
On Sat, Mar 28, 2020 at 4:18 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Fri, Mar 27, 2020 at 04:47:10PM -0400, Al Cooper wrote:
> > 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.
>
> I'm not sure this has been tested. See below.
>
> ...
>
> > +#include <linux/acpi.h>
> > +#include <linux/of.h>
>
> I didn;t find evidence these are needed.

I removed them.

>
> ...
>
>
> > +     res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,
> > +                                      (val != frame_idx), 1, 130);
>
> Too many parentheses.
>

Fixed

> > +     if (res)
> > +             dev_err(ehci_to_hcd(ehci)->self.controller,
> > +                     "Error waiting for SOF\n");
>
> ...
>
> > +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;
>
> I'm not sure it was an intention to leave a lot of dead code below.
>

Fixed.

> > +     /* Hook the hub control routine to work around a bug */
>
> > +     if (org_hub_control == NULL)
>
>         if (!org_hub_control) ?
>

Changed.

> > +             org_hub_control = ehci_brcm_hc_driver.hub_control;
> > +     ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;
>
> > +     device_wakeup_enable(hcd->self.controller);
> > +     device_enable_async_suspend(hcd->self.controller);
> > +     platform_set_drvdata(pdev, hcd);
> > +
>
> > +     return err;
>
>         return 0; ?
>
Changed.


> > +err_clk:
> > +     clk_disable_unprepare(priv->clk);
> > +err_hcd:
> > +     usb_put_hcd(hcd);
> > +
> > +     return err;
> > +}
>
> ...
>
> > +#ifdef CONFIG_PM_SLEEP
>
> You also can use __maybe_unused annotations.
>

Changed.

> > +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;
>
> So, if you fail to suspend the device, clocks will become unusable, how to recover from such case?
>

Changed to handle the failure.

> > +}
>
> > +#endif /* CONFIG_PM_SLEEP */
>
> ...
>
> > +MODULE_DESCRIPTION(BRCM_DRIVER_DESC);
>
> Better to have it explicit.
>

Changed.

> --
> With Best Regards,
> Andy Shevchenko
>
>

v3 coming.
Thanks again for the review
Al
diff mbox series

Patch

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");