Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932531Ab2JNOoc (ORCPT ); Sun, 14 Oct 2012 10:44:32 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46825 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932486Ab2JNOoY (ORCPT ); Sun, 14 Oct 2012 10:44:24 -0400 Message-Id: <20121014143537.047362248@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 14 Oct 2012 15:35:57 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Elric Fu , Sarah Sharp , Miroslav Sabljic Subject: [ 024/147] xHCI: add aborting command ring function In-Reply-To: <20121014143533.742627615@decadent.org.uk> X-SA-Exim-Connect-IP: 77.75.106.1 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8182 Lines: 246 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Elric Fu commit b92cc66c047ff7cf587b318fe377061a353c120f upstream. Software have to abort command ring and cancel command when a command is failed or hang. Otherwise, the command ring will hang up and can't handle the others. An example of a command that may hang is the Address Device Command, because waiting for a SET_ADDRESS request to be acknowledged by a USB device is outside of the xHC's ability to control. To cancel a command, software will initialize a command descriptor for the cancel command, and add it into a cancel_cmd_list of xhci. Sarah: Fixed missing newline on "Have the command ring been stopped?" debugging statement. This patch should be backported to kernels as old as 3.0, that contain the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an assertion to check for virt_dev=0 bug." That commit papers over a NULL pointer dereference, and this patch fixes the underlying issue that caused the NULL pointer dereference. Signed-off-by: Elric Fu Signed-off-by: Sarah Sharp Tested-by: Miroslav Sabljic Signed-off-by: Ben Hutchings --- drivers/usb/host/xhci-mem.c | 7 +++ drivers/usb/host/xhci-ring.c | 108 ++++++++++++++++++++++++++++++++++++++++++ drivers/usb/host/xhci.c | 2 +- drivers/usb/host/xhci.h | 12 +++++ 4 files changed, 128 insertions(+), 1 deletion(-) --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1680,6 +1680,7 @@ void xhci_mem_cleanup(struct xhci_hcd *x { struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller); struct dev_info *dev_info, *next; + struct xhci_cd *cur_cd, *next_cd; unsigned long flags; int size; int i, j, num_ports; @@ -1701,6 +1702,11 @@ void xhci_mem_cleanup(struct xhci_hcd *x xhci_ring_free(xhci, xhci->cmd_ring); xhci->cmd_ring = NULL; xhci_dbg(xhci, "Freed command ring\n"); + list_for_each_entry_safe(cur_cd, next_cd, + &xhci->cancel_cmd_list, cancel_cmd_list) { + list_del(&cur_cd->cancel_cmd_list); + kfree(cur_cd); + } for (i = 1; i < MAX_HC_SLOTS; ++i) xhci_free_virt_device(xhci, i); @@ -2246,6 +2252,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, xhci->cmd_ring = xhci_ring_alloc(xhci, 1, true, false, flags); if (!xhci->cmd_ring) goto fail; + INIT_LIST_HEAD(&xhci->cancel_cmd_list); xhci_dbg(xhci, "Allocated command ring at %p\n", xhci->cmd_ring); xhci_dbg(xhci, "First segment DMA is 0x%llx\n", (unsigned long long)xhci->cmd_ring->first_seg->dma); --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -318,6 +318,114 @@ void xhci_ring_cmd_db(struct xhci_hcd *x xhci_readl(xhci, &xhci->dba->doorbell[0]); } +static int xhci_abort_cmd_ring(struct xhci_hcd *xhci) +{ + u64 temp_64; + int ret; + + xhci_dbg(xhci, "Abort command ring\n"); + + if (!(xhci->cmd_ring_state & CMD_RING_STATE_RUNNING)) { + xhci_dbg(xhci, "The command ring isn't running, " + "Have the command ring been stopped?\n"); + return 0; + } + + temp_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring); + if (!(temp_64 & CMD_RING_RUNNING)) { + xhci_dbg(xhci, "Command ring had been stopped\n"); + return 0; + } + xhci->cmd_ring_state = CMD_RING_STATE_ABORTED; + xhci_write_64(xhci, temp_64 | CMD_RING_ABORT, + &xhci->op_regs->cmd_ring); + + /* Section 4.6.1.2 of xHCI 1.0 spec says software should + * time the completion od all xHCI commands, including + * the Command Abort operation. If software doesn't see + * CRR negated in a timely manner (e.g. longer than 5 + * seconds), then it should assume that the there are + * larger problems with the xHC and assert HCRST. + */ + ret = handshake(xhci, &xhci->op_regs->cmd_ring, + CMD_RING_RUNNING, 0, 5 * 1000 * 1000); + if (ret < 0) { + xhci_err(xhci, "Stopped the command ring failed, " + "maybe the host is dead\n"); + xhci->xhc_state |= XHCI_STATE_DYING; + xhci_quiesce(xhci); + xhci_halt(xhci); + return -ESHUTDOWN; + } + + return 0; +} + +static int xhci_queue_cd(struct xhci_hcd *xhci, + struct xhci_command *command, + union xhci_trb *cmd_trb) +{ + struct xhci_cd *cd; + cd = kzalloc(sizeof(struct xhci_cd), GFP_ATOMIC); + if (!cd) + return -ENOMEM; + INIT_LIST_HEAD(&cd->cancel_cmd_list); + + cd->command = command; + cd->cmd_trb = cmd_trb; + list_add_tail(&cd->cancel_cmd_list, &xhci->cancel_cmd_list); + + return 0; +} + +/* + * Cancel the command which has issue. + * + * Some commands may hang due to waiting for acknowledgement from + * usb device. It is outside of the xHC's ability to control and + * will cause the command ring is blocked. When it occurs software + * should intervene to recover the command ring. + * See Section 4.6.1.1 and 4.6.1.2 + */ +int xhci_cancel_cmd(struct xhci_hcd *xhci, struct xhci_command *command, + union xhci_trb *cmd_trb) +{ + int retval = 0; + unsigned long flags; + + spin_lock_irqsave(&xhci->lock, flags); + + if (xhci->xhc_state & XHCI_STATE_DYING) { + xhci_warn(xhci, "Abort the command ring," + " but the xHCI is dead.\n"); + retval = -ESHUTDOWN; + goto fail; + } + + /* queue the cmd desriptor to cancel_cmd_list */ + retval = xhci_queue_cd(xhci, command, cmd_trb); + if (retval) { + xhci_warn(xhci, "Queuing command descriptor failed.\n"); + goto fail; + } + + /* abort command ring */ + retval = xhci_abort_cmd_ring(xhci); + if (retval) { + xhci_err(xhci, "Abort command ring failed\n"); + if (unlikely(retval == -ESHUTDOWN)) { + spin_unlock_irqrestore(&xhci->lock, flags); + usb_hc_died(xhci_to_hcd(xhci)->primary_hcd); + xhci_dbg(xhci, "xHCI host controller is dead.\n"); + return retval; + } + } + +fail: + spin_unlock_irqrestore(&xhci->lock, flags); + return retval; +} + void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id, unsigned int ep_index, --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -52,7 +52,7 @@ MODULE_PARM_DESC(link_quirk, "Don't clea * handshake done). There are two failure modes: "usec" have passed (major * hardware flakeout), or the register reads as all-ones (hardware removed). */ -static int handshake(struct xhci_hcd *xhci, void __iomem *ptr, +int handshake(struct xhci_hcd *xhci, void __iomem *ptr, u32 mask, u32 done, int usec) { u32 result; --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1255,6 +1255,13 @@ struct xhci_td { union xhci_trb *last_trb; }; +/* command descriptor */ +struct xhci_cd { + struct list_head cancel_cmd_list; + struct xhci_command *command; + union xhci_trb *cmd_trb; +}; + struct xhci_dequeue_state { struct xhci_segment *new_deq_seg; union xhci_trb *new_deq_ptr; @@ -1406,6 +1413,7 @@ struct xhci_hcd { #define CMD_RING_STATE_RUNNING (1 << 0) #define CMD_RING_STATE_ABORTED (1 << 1) #define CMD_RING_STATE_STOPPED (1 << 2) + struct list_head cancel_cmd_list; unsigned int cmd_ring_reserved_trbs; struct xhci_ring *event_ring; struct xhci_erst erst; @@ -1670,6 +1678,8 @@ static inline void xhci_unregister_pci(v /* xHCI host controller glue */ typedef void (*xhci_get_quirks_t)(struct device *, struct xhci_hcd *); +int handshake(struct xhci_hcd *xhci, void __iomem *ptr, + u32 mask, u32 done, int usec); void xhci_quiesce(struct xhci_hcd *xhci); int xhci_halt(struct xhci_hcd *xhci); int xhci_reset(struct xhci_hcd *xhci); @@ -1760,6 +1770,8 @@ void xhci_queue_config_ep_quirk(struct x unsigned int slot_id, unsigned int ep_index, struct xhci_dequeue_state *deq_state); void xhci_stop_endpoint_command_watchdog(unsigned long arg); +int xhci_cancel_cmd(struct xhci_hcd *xhci, struct xhci_command *command, + union xhci_trb *cmd_trb); void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id, unsigned int ep_index, unsigned int stream_id); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/