diff mbox series

[v9,4/5] usb: ehci: Add new EHCI driver for Broadcom STB SoC's

Message ID 20200511193643.30926-5-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State Superseded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 May 11, 2020, 7:36 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 work around bugs in the EHCI
controller. The primary workaround is for a bug where the Core
violates the SOF interval between the first two SOFs transmitted after
resume. This only happens if the resume occurs near the end of a
microframe. The fix is to intercept the ehci-hcd request to complete
RESUME and align it to the start of the next microframe.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/usb/host/ehci-brcm.c | 280 +++++++++++++++++++++++++++++++++++
 1 file changed, 280 insertions(+)
 create mode 100644 drivers/usb/host/ehci-brcm.c

Comments

Alan Stern May 11, 2020, 7:51 p.m. UTC | #1
On Mon, 11 May 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 work around bugs in the EHCI
> controller. The primary workaround is for a bug where the Core
> violates the SOF interval between the first two SOFs transmitted after
> resume. This only happens if the resume occurs near the end of a
> microframe. The fix is to intercept the ehci-hcd request to complete
> RESUME and align it to the start of the next microframe.
> 
> Signed-off-by: Al Cooper <alcooperx@gmail.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> ---

I hate to point this out...

> +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;
> +
> +	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +	if (err)
> +		return err;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq <= 0)
> +		return irq ? irq : EINVAL;

That should be -EINVAL.

To tell the truth, I'm not sure it's worthwhile checking for irq == 0.  
That's up to Greg to decide.

Anyway, as far as I'm concerned you can either change EINVAL to -EINVAL
or change the whole thing back to "if (irq < 0) return irq;".  Either
way, you may add:

Acked-by: Alan Stern <stern@rowland.harvard.edu>

Alan Stern
Alan Cooper May 12, 2020, 2:24 p.m. UTC | #2
On Mon, May 11, 2020 at 3:51 PM Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Mon, 11 May 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 work around bugs in the EHCI
> > controller. The primary workaround is for a bug where the Core
> > violates the SOF interval between the first two SOFs transmitted after
> > resume. This only happens if the resume occurs near the end of a
> > microframe. The fix is to intercept the ehci-hcd request to complete
> > RESUME and align it to the start of the next microframe.
> >
> > Signed-off-by: Al Cooper <alcooperx@gmail.com>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> > ---
>
> I hate to point this out...
>
> > +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;
> > +
> > +     err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> > +     if (err)
> > +             return err;
> > +
> > +     irq = platform_get_irq(pdev, 0);
> > +     if (irq <= 0)
> > +             return irq ? irq : EINVAL;
>
> That should be -EINVAL.
>
> To tell the truth, I'm not sure it's worthwhile checking for irq == 0.
> That's up to Greg to decide.

Darn, I've been looking at this code for too long :(
Since Greg originally requested <=, I'll fix this and send v10.

Thanks
Al

>
> Anyway, as far as I'm concerned you can either change EINVAL to -EINVAL
> or change the whole thing back to "if (irq < 0) return irq;".  Either
> way, you may add:
>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
>
> Alan Stern
>
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..9cb0ebdd2925
--- /dev/null
+++ b/drivers/usb/host/ehci-brcm.c
@@ -0,0 +1,280 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Broadcom */
+
+#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/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/iopoll.h>
+
+#include "ehci.h"
+
+#define hcd_to_ehci_priv(h) ((struct brcm_priv *)hcd_to_ehci(h)->priv)
+
+struct brcm_priv {
+	struct clk *clk;
+};
+
+/*
+ * 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)
+		ehci_err(ehci, "Error waiting for SOF\n");
+	udelay(delay);
+}
+
+/*
+ * ehci_brcm_hub_control
+ * The EHCI controller has a bug where it can violate the SOF
+ * interval between the first two SOF's transmitted after resume
+ * if the resume occurs near the end of the microframe. This causees
+ * the controller to detect babble on the suspended port and
+ * will eventually cause the controller to reset the port.
+ * The fix is to Intercept the echi-hcd request to complete RESUME and
+ * align it to the start of the next microframe.
+ * 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;
+	unsigned long flags;
+	int retval, irq_disabled = 0;
+
+	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
+
+	/*
+	 * 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 = ehci_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);
+	int len;
+
+	ehci->big_endian_mmio = 1;
+
+	ehci->caps = (void __iomem *)hcd->regs;
+	len = HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
+	ehci->regs = (void __iomem *)(hcd->regs + len);
+
+	/* 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;
+
+	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (err)
+		return err;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0)
+		return irq ? irq : EINVAL;
+
+	/* Hook the hub control routine to work around a bug */
+	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;
+
+	hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &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);
+
+	return 0;
+
+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;
+}
+
+static int __maybe_unused 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);
+	if (ret)
+		return ret;
+	clk_disable_unprepare(priv->clk);
+	return 0;
+}
+
+static int __maybe_unused 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);
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+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("EHCI Broadcom STB driver");
+MODULE_AUTHOR("Al Cooper");
+MODULE_LICENSE("GPL");