From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933281Ab0GAVes (ORCPT ); Thu, 1 Jul 2010 17:34:48 -0400 Received: from kroah.org ([198.145.64.141]:33084 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932632Ab0GAVOz (ORCPT ); Thu, 1 Jul 2010 17:14:55 -0400 X-Mailbox-Line: From gregkh@clark.site Thu Jul 1 10:42:59 2010 Message-Id: <20100701174259.485551438@clark.site> User-Agent: quilt/0.48-10.1 Date: Thu, 01 Jul 2010 10:44:04 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Sarah Sharp Subject: [154/200] USB: xhci: Wait for host to start running. In-Reply-To: <20100701175201.GA2149@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.34-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sarah Sharp commit ed07453fd356025cc25272629e982f5e4607632c upstream. When the run bit is set in the xHCI command register, it may take a few microseconds for the host to start running. We cannot ring any doorbells until the host is actually running, so wait until the status register says the host is running. Signed-off-by: Sarah Sharp Reported-by: Shinya Saito Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 39 ++++++++++++++++++++++++++++++++------- 1 file changed, 32 insertions(+), 7 deletions(-) --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -105,6 +105,33 @@ int xhci_halt(struct xhci_hcd *xhci) } /* + * Set the run bit and wait for the host to be running. + */ +int xhci_start(struct xhci_hcd *xhci) +{ + u32 temp; + int ret; + + temp = xhci_readl(xhci, &xhci->op_regs->command); + temp |= (CMD_RUN); + xhci_dbg(xhci, "// Turn on HC, cmd = 0x%x.\n", + temp); + xhci_writel(xhci, temp, &xhci->op_regs->command); + + /* + * Wait for the HCHalted Status bit to be 0 to indicate the host is + * running. + */ + ret = handshake(xhci, &xhci->op_regs->status, + STS_HALT, 0, XHCI_MAX_HALT_USEC); + if (ret == -ETIMEDOUT) + xhci_err(xhci, "Host took too long to start, " + "waited %u microseconds.\n", + XHCI_MAX_HALT_USEC); + return ret; +} + +/* * Reset a halted HC, and set the internal HC state to HC_STATE_HALT. * * This resets pipelines, timers, counters, state machines, etc. @@ -452,13 +479,11 @@ int xhci_run(struct usb_hcd *hcd) if (NUM_TEST_NOOPS > 0) doorbell = xhci_setup_one_noop(xhci); - temp = xhci_readl(xhci, &xhci->op_regs->command); - temp |= (CMD_RUN); - xhci_dbg(xhci, "// Turn on HC, cmd = 0x%x.\n", - temp); - xhci_writel(xhci, temp, &xhci->op_regs->command); - /* Flush PCI posted writes */ - temp = xhci_readl(xhci, &xhci->op_regs->command); + if (xhci_start(xhci)) { + xhci_halt(xhci); + return -ENODEV; + } + xhci_dbg(xhci, "// @%p = 0x%x\n", &xhci->op_regs->command, temp); if (doorbell) (*doorbell)(xhci);