From: "Singh, Sandeep" <Sandeep.Singh@amd.com> To: "kai.heng.feng@canonical.com" <kai.heng.feng@canonical.com>, "mathias.nyman@intel.com" <mathias.nyman@intel.com>, "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>, "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Cc: "Singh, Sandeep" <Sandeep.Singh@amd.com>, "S-k, Shyam-sundar" <Shyam-sundar.S-k@amd.com>, "Singh, Sandeep" <Sandeep.Singh@amd.com>, "Shah, Nehal-bakulchandra" <Nehal-bakulchandra.Shah@amd.com> Subject: [PATCH v3] xhci: workaround CSS timeout on AMD SNPS 3.0 xHC Date: Fri, 23 Nov 2018 16:24:01 +0000 [thread overview] Message-ID: <1542990218-30495-1-git-send-email-Sandeep.Singh@amd.com> (raw) From: Sandeep Singh <sandeep.singh@amd.com> Occasionally AMD SNPS 3.0 xHC does not respond to CSS when set, also it does not flag anything on SRE and HCE to point the internal xHC errors on USBSTS register. This stalls the entire system wide suspend and there is no point in stalling just because of xHC CSS is not responding. To work around this problem, if the xHC does not flag anything on SRE and HCE, we can skip the CSS timeout and allow the system to continue the suspend. Once the system resume happens we can internally reset the controller using XHCI_RESET_ON_RESUME quirk Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com> Signed-off-by: Sandeep Singh <Sandeep.Singh@amd.com> cc: Nehal Shah <Nehal-bakulchandra.Shah@amd.com> --- Changes since v1: -> New Variable based decision making when SNPS issue happens hence -> quirk interdependency removed. -> Removed STS conditional check in suspend function. Changes since v2: -> Updated quirk bit as per Kai-heng comment. drivers/usb/host/xhci-pci.c | 4 ++++ drivers/usb/host/xhci.c | 26 ++++++++++++++++++++++---- drivers/usb/host/xhci.h | 3 +++ 3 files changed, 29 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index a951526..a9ec705 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -139,6 +139,10 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) pdev->device == 0x43bb)) xhci->quirks |= XHCI_SUSPEND_DELAY; + if (pdev->vendor == PCI_VENDOR_ID_AMD && + (pdev->device == 0x15e0 || pdev->device == 0x15e1)) + xhci->quirks |= XHCI_SNPS_BROKEN_SUSPEND; + if (pdev->vendor == PCI_VENDOR_ID_AMD) xhci->quirks |= XHCI_TRUST_TX_LENGTH; diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index c928dbb..c20b85e 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -968,6 +968,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup) unsigned int delay = XHCI_MAX_HALT_USEC; struct usb_hcd *hcd = xhci_to_hcd(xhci); u32 command; + u32 res; if (!hcd->state) return 0; @@ -1021,11 +1022,28 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup) command = readl(&xhci->op_regs->command); command |= CMD_CSS; writel(command, &xhci->op_regs->command); + xhci->broken_suspend = 0; if (xhci_handshake(&xhci->op_regs->status, STS_SAVE, 0, 10 * 1000)) { - xhci_warn(xhci, "WARN: xHC save state timeout\n"); - spin_unlock_irq(&xhci->lock); - return -ETIMEDOUT; + /* + * AMD SNPS xHC 3.0 occasionally does not clear the + * SSS bit of USBSTS and when driver tries to poll + * to see if the xHC clears BIT(8) which never happens + * and driver assumes that controller is not responding + * and times out. To workaround this, its good to check + * if SRE and HCE bits are not set (as per xhci + * Section 5.4.2) and bypass the timeout. + */ + res = readl(&xhci->op_regs->status); + if ((xhci->quirks & XHCI_SNPS_BROKEN_SUSPEND) && + (((res & STS_SRE) == 0) && + ((res & STS_HCE) == 0))) { + xhci->broken_suspend = 1; + } else { + xhci_warn(xhci, "WARN: xHC save state timeout\n"); + spin_unlock_irq(&xhci->lock); + return -ETIMEDOUT; + } } spin_unlock_irq(&xhci->lock); @@ -1078,7 +1096,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags); spin_lock_irq(&xhci->lock); - if (xhci->quirks & XHCI_RESET_ON_RESUME) + if ((xhci->quirks & XHCI_RESET_ON_RESUME) || xhci->broken_suspend) hibernated = true; if (!hibernated) { diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 260b259..c3515ba 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1850,6 +1850,7 @@ struct xhci_hcd { #define XHCI_ZERO_64B_REGS BIT_ULL(32) #define XHCI_DEFAULT_PM_RUNTIME_ALLOW BIT_ULL(33) #define XHCI_RESET_PLL_ON_DISCONNECT BIT_ULL(34) +#define XHCI_SNPS_BROKEN_SUSPEND BIT_ULL(35) unsigned int num_active_eps; unsigned int limit_active_eps; @@ -1879,6 +1880,8 @@ struct xhci_hcd { void *dbc; /* platform-specific data -- must come last */ unsigned long priv[0] __aligned(sizeof(s64)); + /* Broken Suspend flag for SNPS Suspend resume issue */ + u8 broken_suspend; }; /* Platform specific overrides to generic XHCI hc_driver ops */ -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Sandeep Singh <Sandeep.Singh@amd.com> To: "kai.heng.feng@canonical.com" <kai.heng.feng@canonical.com>, "mathias.nyman@intel.com" <mathias.nyman@intel.com>, "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>, "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Cc: "Singh, Sandeep" <Sandeep.Singh@amd.com>, "S-k, Shyam-sundar" <Shyam-sundar.S-k@amd.com>"Singh, Sandeep" <Sandeep.Singh@amd.com>, "Shah, Nehal-bakulchandra" <Nehal-bakulchandra.Shah@amd.com> Subject: [v3] xhci: workaround CSS timeout on AMD SNPS 3.0 xHC Date: Fri, 23 Nov 2018 16:24:01 +0000 [thread overview] Message-ID: <1542990218-30495-1-git-send-email-Sandeep.Singh@amd.com> (raw) From: Sandeep Singh <sandeep.singh@amd.com> Occasionally AMD SNPS 3.0 xHC does not respond to CSS when set, also it does not flag anything on SRE and HCE to point the internal xHC errors on USBSTS register. This stalls the entire system wide suspend and there is no point in stalling just because of xHC CSS is not responding. To work around this problem, if the xHC does not flag anything on SRE and HCE, we can skip the CSS timeout and allow the system to continue the suspend. Once the system resume happens we can internally reset the controller using XHCI_RESET_ON_RESUME quirk Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com> Signed-off-by: Sandeep Singh <Sandeep.Singh@amd.com> cc: Nehal Shah <Nehal-bakulchandra.Shah@amd.com> --- Changes since v1: -> New Variable based decision making when SNPS issue happens hence -> quirk interdependency removed. -> Removed STS conditional check in suspend function. Changes since v2: -> Updated quirk bit as per Kai-heng comment. drivers/usb/host/xhci-pci.c | 4 ++++ drivers/usb/host/xhci.c | 26 ++++++++++++++++++++++---- drivers/usb/host/xhci.h | 3 +++ 3 files changed, 29 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index a951526..a9ec705 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -139,6 +139,10 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) pdev->device == 0x43bb)) xhci->quirks |= XHCI_SUSPEND_DELAY; + if (pdev->vendor == PCI_VENDOR_ID_AMD && + (pdev->device == 0x15e0 || pdev->device == 0x15e1)) + xhci->quirks |= XHCI_SNPS_BROKEN_SUSPEND; + if (pdev->vendor == PCI_VENDOR_ID_AMD) xhci->quirks |= XHCI_TRUST_TX_LENGTH; diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index c928dbb..c20b85e 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -968,6 +968,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup) unsigned int delay = XHCI_MAX_HALT_USEC; struct usb_hcd *hcd = xhci_to_hcd(xhci); u32 command; + u32 res; if (!hcd->state) return 0; @@ -1021,11 +1022,28 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup) command = readl(&xhci->op_regs->command); command |= CMD_CSS; writel(command, &xhci->op_regs->command); + xhci->broken_suspend = 0; if (xhci_handshake(&xhci->op_regs->status, STS_SAVE, 0, 10 * 1000)) { - xhci_warn(xhci, "WARN: xHC save state timeout\n"); - spin_unlock_irq(&xhci->lock); - return -ETIMEDOUT; + /* + * AMD SNPS xHC 3.0 occasionally does not clear the + * SSS bit of USBSTS and when driver tries to poll + * to see if the xHC clears BIT(8) which never happens + * and driver assumes that controller is not responding + * and times out. To workaround this, its good to check + * if SRE and HCE bits are not set (as per xhci + * Section 5.4.2) and bypass the timeout. + */ + res = readl(&xhci->op_regs->status); + if ((xhci->quirks & XHCI_SNPS_BROKEN_SUSPEND) && + (((res & STS_SRE) == 0) && + ((res & STS_HCE) == 0))) { + xhci->broken_suspend = 1; + } else { + xhci_warn(xhci, "WARN: xHC save state timeout\n"); + spin_unlock_irq(&xhci->lock); + return -ETIMEDOUT; + } } spin_unlock_irq(&xhci->lock); @@ -1078,7 +1096,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags); spin_lock_irq(&xhci->lock); - if (xhci->quirks & XHCI_RESET_ON_RESUME) + if ((xhci->quirks & XHCI_RESET_ON_RESUME) || xhci->broken_suspend) hibernated = true; if (!hibernated) { diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 260b259..c3515ba 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1850,6 +1850,7 @@ struct xhci_hcd { #define XHCI_ZERO_64B_REGS BIT_ULL(32) #define XHCI_DEFAULT_PM_RUNTIME_ALLOW BIT_ULL(33) #define XHCI_RESET_PLL_ON_DISCONNECT BIT_ULL(34) +#define XHCI_SNPS_BROKEN_SUSPEND BIT_ULL(35) unsigned int num_active_eps; unsigned int limit_active_eps; @@ -1879,6 +1880,8 @@ struct xhci_hcd { void *dbc; /* platform-specific data -- must come last */ unsigned long priv[0] __aligned(sizeof(s64)); + /* Broken Suspend flag for SNPS Suspend resume issue */ + u8 broken_suspend; }; /* Platform specific overrides to generic XHCI hc_driver ops */
next reply other threads:[~2018-11-23 16:24 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-23 16:24 Singh, Sandeep [this message] 2018-11-23 16:24 ` [v3] xhci: workaround CSS timeout on AMD SNPS 3.0 xHC Sandeep Singh 2018-11-27 7:44 ` [PATCH v3] " Kai Heng Feng 2018-11-27 7:44 ` [v3] " Kai-Heng Feng 2018-11-27 11:48 ` [PATCH v3] " Mathias Nyman 2018-11-27 11:48 ` [v3] " Mathias Nyman
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