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137 lines
3.9 KiB
137 lines
3.9 KiB
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Sat, 1 Oct 2016 22:54:48 +0200
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Subject: [PATCH] usb: xhci: add support for performing fake doorbell
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Broadcom's Northstar XHCI controllers seem to need a special start
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procedure to work correctly. There isn't any official documentation of
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this, the problem is that controller doesn't detect any connected
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devices with default setup. Moreover connecting USB device to controller
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that doesn't run properly can cause SoC's watchdog issues.
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A workaround that was successfully tested on multiple devices is to
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perform a fake doorbell. This patch adds code for doing this and enables
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it on BCM4708 family.
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---
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drivers/usb/host/xhci-plat.c | 6 +++++
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drivers/usb/host/xhci.c | 63 +++++++++++++++++++++++++++++++++++++++++---
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drivers/usb/host/xhci.h | 1 +
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3 files changed, 67 insertions(+), 3 deletions(-)
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--- a/drivers/usb/host/xhci-plat.c
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+++ b/drivers/usb/host/xhci-plat.c
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@@ -67,12 +67,18 @@ static int xhci_priv_resume_quirk(struct
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static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
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{
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+ struct platform_device *pdev = to_platform_device(dev);
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+ struct device_node *node = pdev->dev.of_node;
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+
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/*
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* As of now platform drivers don't provide MSI support so we ensure
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* here that the generic code does not try to make a pci_dev from our
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* dev struct in order to setup MSI
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*/
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xhci->quirks |= XHCI_PLAT;
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+
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+ if (node && of_machine_is_compatible("brcm,bcm4708"))
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+ xhci->quirks |= XHCI_FAKE_DOORBELL;
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}
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/* called during probe() after chip reset completes */
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--- a/drivers/usb/host/xhci.c
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+++ b/drivers/usb/host/xhci.c
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@@ -168,6 +168,49 @@ int xhci_start(struct xhci_hcd *xhci)
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return ret;
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}
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+/**
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+ * xhci_fake_doorbell - Perform a fake doorbell on a specified slot
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+ *
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+ * Some controllers require a fake doorbell to start correctly. Without that
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+ * they simply don't detect any devices.
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+ */
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+static int xhci_fake_doorbell(struct xhci_hcd *xhci, int slot_id)
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+{
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+ u32 temp;
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+
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+ /* Alloc a virt device for that slot */
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+ if (!xhci_alloc_virt_device(xhci, slot_id, NULL, GFP_NOIO)) {
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+ xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
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+ return -ENOMEM;
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+ }
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+
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+ /* Ring fake doorbell for slot_id ep 0 */
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+ xhci_ring_ep_doorbell(xhci, slot_id, 0, 0);
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+ usleep_range(1000, 1500);
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+
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+ /* Read the status to check if HSE is set or not */
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+ temp = readl(&xhci->op_regs->status);
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+
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+ /* Clear HSE if set */
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+ if (temp & STS_FATAL) {
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+ xhci_dbg(xhci, "HSE problem detected, status: 0x%08x\n", temp);
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+ temp &= ~0x1fff;
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+ temp |= STS_FATAL;
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+ writel(temp, &xhci->op_regs->status);
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+ usleep_range(1000, 1500);
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+ readl(&xhci->op_regs->status);
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+ }
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+
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+ /* Free virt device */
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+ xhci_free_virt_device(xhci, slot_id);
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+
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+ /* We're done if controller is already running */
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+ if (readl(&xhci->op_regs->command) & CMD_RUN)
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+ return 0;
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+
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+ return xhci_start(xhci);
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+}
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+
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/*
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* Reset a halted HC.
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*
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@@ -551,10 +594,20 @@ static int xhci_init(struct usb_hcd *hcd
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static int xhci_run_finished(struct xhci_hcd *xhci)
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{
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- if (xhci_start(xhci)) {
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- xhci_halt(xhci);
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- return -ENODEV;
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+ int err;
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+
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+ err = xhci_start(xhci);
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+ if (err) {
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+ err = -ENODEV;
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+ goto err_halt;
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}
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+
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+ if (xhci->quirks & XHCI_FAKE_DOORBELL) {
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+ err = xhci_fake_doorbell(xhci, 1);
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+ if (err)
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+ goto err_halt;
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+ }
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+
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xhci->shared_hcd->state = HC_STATE_RUNNING;
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xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
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@@ -564,6 +617,10 @@ static int xhci_run_finished(struct xhci
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xhci_dbg_trace(xhci, trace_xhci_dbg_init,
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"Finished xhci_run for USB3 roothub");
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return 0;
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+
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+err_halt:
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+ xhci_halt(xhci);
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+ return err;
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}
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/*
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--- a/drivers/usb/host/xhci.h
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+++ b/drivers/usb/host/xhci.h
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@@ -1835,6 +1835,7 @@ struct xhci_hcd {
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#define XHCI_LIMIT_ENDPOINT_INTERVAL_7 (1 << 26)
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#define XHCI_U2_DISABLE_WAKE (1 << 27)
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#define XHCI_ASMEDIA_MODIFY_FLOWCONTROL (1 << 28)
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+#define XHCI_FAKE_DOORBELL (1 << 29)
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#define XHCI_SUSPEND_DELAY (1 << 30)
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unsigned int num_active_eps;
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