On Wed, Jan 23, 2013 at 12:13:28PM -0600, [email protected] wrote: > From: Suravee Suthikulpanit <[email protected]> > > Changes from V1: > * Fix logic that check the processor model. > * Clear writing enable bit after apply the workaround > * Change function name
You need a proper commit message... > Signed-off-by: Suravee Suthikulpanit <[email protected]> > > diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c > index 81837b0..a04b20a 100644 > --- a/drivers/iommu/amd_iommu_init.c > +++ b/drivers/iommu/amd_iommu_init.c > @@ -975,6 +975,37 @@ static void __init free_iommu_all(void) > } > > /* > + * AMD family15h Model 10h-1fh erratum 746 (IOMMU Logging May Stall > Translations) > + * Workaround: > + * BIOS should disable L2B micellaneous clock gating by setting > + * L2_L2B_CK_GATE_CONTROL[CKGateL2BMiscDisable](D0F2xF4_x90[2]) = 1b > + */ ... like this one, for example. You could explain what the erratum does and what the workaround is in the commit message. > +static void __init amd_iommu_erratum_746_workaround(struct amd_iommu *iommu) > +{ > + u32 value; > + > + if ((boot_cpu_data.x86 != 0x15) || > + (boot_cpu_data.x86_model < 0x10) || > + (boot_cpu_data.x86_model > 0x1f)) > + return; > + > + pci_write_config_dword(iommu->dev, 0xf0, 0x90); > + pci_read_config_dword(iommu->dev, 0xf4, &value); > + > + if (!(value & 0x4)) { Save an indentation level by reversing the logic here: if (value & BIT(2)) return; /* Select NB... > + /* Select Northbridge indirect register 0x90 and enable writing > */ > + pci_write_config_dword(iommu->dev, 0xf0, 0x90 | (1 << 8)); > + > + pci_write_config_dword(iommu->dev, 0xf4, value | 0x4); > + pr_info("AMD-Vi: Applying erratum 746 workaround for IOMMU at > %s\n", > + dev_name(&iommu->dev->dev)); > + > + /* Clear the enable writing bit */ > + pci_write_config_dword(iommu->dev, 0xf0, 0x90); > + } > +} > + > +/* > * This function clues the initialization function for one IOMMU > * together and also allocates the command buffer and programs the > * hardware. It does NOT enable the IOMMU. This is done afterwards. > @@ -1171,6 +1202,8 @@ static int iommu_init_pci(struct amd_iommu *iommu) > for (i = 0; i < 0x83; i++) > iommu->stored_l2[i] = iommu_read_l2(iommu, i); > } > + > + amd_iommu_erratum_746_workaround(iommu); > > return pci_enable_device(iommu->dev); Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
