| Message ID | 1509132569-9398-8-git-send-email-mmaddireddy@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Saturday 28 October 2017 12:59 AM, Manikanta Maddireddy wrote: > When there are 32 outstanding writes from AFI to memory, the outstanding > write counter overflows and indicates that there are "0" outstanding write > transactions. This outstanding write counter is used to generate IDLE > signal to dynamically gate the AFI clock. > > When memory controller is under heavy load, its possible that write > completions will come back to AFI after long delay and AFI write counter > overflows. AFI clock gets gated even when there are outstanding > transactions towards memory controller resutling in system hang. > > Disable dynamic clock gating of AFI clock to avoid system hang. > > Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com> > --- > drivers/pci/host/pci-tegra.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c > index 27a8211c48b2..b8cac871712b 100644 > --- a/drivers/pci/host/pci-tegra.c > +++ b/drivers/pci/host/pci-tegra.c > @@ -103,8 +103,9 @@ > #define AFI_MSI_EN_VEC6 0xa4 > #define AFI_MSI_EN_VEC7 0xa8 > > -#define AFI_CONFIGURATION 0xac > -#define AFI_CONFIGURATION_EN_FPCI (1 << 0) > +#define AFI_CONFIGURATION 0xac > +#define AFI_CONFIGURATION_EN_FPCI (1 << 0) > +#define AFI_CONFIGURATION_CLKEN_OVERRIDE (1 << 31) BIT macro is preferred here. > > #define AFI_FPCI_ERROR_MASKS 0xb0 > > @@ -1057,9 +1058,10 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie) > } > } > > - /* finally enable PCIe */ > + /* Disable AFI dynamic clock gating and enable PCIe */ > value = afi_readl(pcie, AFI_CONFIGURATION); > - value |= AFI_CONFIGURATION_EN_FPCI; > + value |= (AFI_CONFIGURATION_EN_FPCI | > + AFI_CONFIGURATION_CLKEN_OVERRIDE); > afi_writel(pcie, value, AFI_CONFIGURATION); > > value = AFI_INTR_EN_INI_SLVERR | AFI_INTR_EN_INI_DECERR |
On 29-Oct-17 3:12 PM, Vidya Sagar wrote: > > > On Saturday 28 October 2017 12:59 AM, Manikanta Maddireddy wrote: >> When there are 32 outstanding writes from AFI to memory, the outstanding >> write counter overflows and indicates that there are "0" outstanding write >> transactions. This outstanding write counter is used to generate IDLE >> signal to dynamically gate the AFI clock. >> >> When memory controller is under heavy load, its possible that write >> completions will come back to AFI after long delay and AFI write counter >> overflows. AFI clock gets gated even when there are outstanding >> transactions towards memory controller resutling in system hang. >> >> Disable dynamic clock gating of AFI clock to avoid system hang. >> >> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com> >> --- >> drivers/pci/host/pci-tegra.c | 10 ++++++---- >> 1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c >> index 27a8211c48b2..b8cac871712b 100644 >> --- a/drivers/pci/host/pci-tegra.c >> +++ b/drivers/pci/host/pci-tegra.c >> @@ -103,8 +103,9 @@ >> #define AFI_MSI_EN_VEC6 0xa4 >> #define AFI_MSI_EN_VEC7 0xa8 >> -#define AFI_CONFIGURATION 0xac >> -#define AFI_CONFIGURATION_EN_FPCI (1 << 0) >> +#define AFI_CONFIGURATION 0xac >> +#define AFI_CONFIGURATION_EN_FPCI (1 << 0) >> +#define AFI_CONFIGURATION_CLKEN_OVERRIDE (1 << 31) > BIT macro is preferred here. Left shift is used everywhere, so to be inline with that I used same format >> #define AFI_FPCI_ERROR_MASKS 0xb0 >> @@ -1057,9 +1058,10 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie) >> } >> } >> - /* finally enable PCIe */ >> + /* Disable AFI dynamic clock gating and enable PCIe */ >> value = afi_readl(pcie, AFI_CONFIGURATION); >> - value |= AFI_CONFIGURATION_EN_FPCI; >> + value |= (AFI_CONFIGURATION_EN_FPCI | >> + AFI_CONFIGURATION_CLKEN_OVERRIDE); >> afi_writel(pcie, value, AFI_CONFIGURATION); >> value = AFI_INTR_EN_INI_SLVERR | AFI_INTR_EN_INI_DECERR | >
From: Manikanta Maddireddy > Sent: 27 October 2017 20:29 > When there are 32 outstanding writes from AFI to memory, the outstanding > write counter overflows and indicates that there are "0" outstanding write > transactions. This outstanding write counter is used to generate IDLE > signal to dynamically gate the AFI clock. > > When memory controller is under heavy load, its possible that write > completions will come back to AFI after long delay and AFI write counter > overflows. AFI clock gets gated even when there are outstanding > transactions towards memory controller resutling in system hang. > > Disable dynamic clock gating of AFI clock to avoid system hang. At least some of the above really ought to be comments in the code. (and with the earlier fix for limiting the number of writes.) David
On 30-Oct-17 9:28 PM, David Laight wrote: > From: Manikanta Maddireddy >> Sent: 27 October 2017 20:29 >> When there are 32 outstanding writes from AFI to memory, the outstanding >> write counter overflows and indicates that there are "0" outstanding write >> transactions. This outstanding write counter is used to generate IDLE >> signal to dynamically gate the AFI clock. >> >> When memory controller is under heavy load, its possible that write >> completions will come back to AFI after long delay and AFI write counter >> overflows. AFI clock gets gated even when there are outstanding >> transactions towards memory controller resutling in system hang. >> >> Disable dynamic clock gating of AFI clock to avoid system hang. > > At least some of the above really ought to be comments in the code. > (and with the earlier fix for limiting the number of writes.) > > David > Ok, will take care of it in next version
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c index 27a8211c48b2..b8cac871712b 100644 --- a/drivers/pci/host/pci-tegra.c +++ b/drivers/pci/host/pci-tegra.c @@ -103,8 +103,9 @@ #define AFI_MSI_EN_VEC6 0xa4 #define AFI_MSI_EN_VEC7 0xa8 -#define AFI_CONFIGURATION 0xac -#define AFI_CONFIGURATION_EN_FPCI (1 << 0) +#define AFI_CONFIGURATION 0xac +#define AFI_CONFIGURATION_EN_FPCI (1 << 0) +#define AFI_CONFIGURATION_CLKEN_OVERRIDE (1 << 31) #define AFI_FPCI_ERROR_MASKS 0xb0 @@ -1057,9 +1058,10 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie) } } - /* finally enable PCIe */ + /* Disable AFI dynamic clock gating and enable PCIe */ value = afi_readl(pcie, AFI_CONFIGURATION); - value |= AFI_CONFIGURATION_EN_FPCI; + value |= (AFI_CONFIGURATION_EN_FPCI | + AFI_CONFIGURATION_CLKEN_OVERRIDE); afi_writel(pcie, value, AFI_CONFIGURATION); value = AFI_INTR_EN_INI_SLVERR | AFI_INTR_EN_INI_DECERR |
When there are 32 outstanding writes from AFI to memory, the outstanding write counter overflows and indicates that there are "0" outstanding write transactions. This outstanding write counter is used to generate IDLE signal to dynamically gate the AFI clock. When memory controller is under heavy load, its possible that write completions will come back to AFI after long delay and AFI write counter overflows. AFI clock gets gated even when there are outstanding transactions towards memory controller resutling in system hang. Disable dynamic clock gating of AFI clock to avoid system hang. Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com> --- drivers/pci/host/pci-tegra.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)