x86/amd-iommu: Reenable AMD IOMMU if it's mysteriously vanished over suspend
AMD's reference BIOS code had a bug that could result in the
firmware failing to reenable the iommu on resume. It
transpires that this causes certain less than desirable
behaviour when it comes to PCI accesses, to whit them ending
up somewhere near Bristol when the more desirable outcome
was Edinburgh. Sadness ensues, perhaps along with filesystem
corruption. Let's make sure that it gets turned back on,
and that we restore its configuration so decisions it makes
bear some resemblance to those made by reasonable people
rather than crack-addled lemurs who spent all your DMA on
Thunderbird.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 5a170cb..44710d8 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -194,6 +194,39 @@
return 1UL << shift;
}
+/* Access to l1 and l2 indexed register spaces */
+
+static u32 iommu_read_l1(struct amd_iommu *iommu, u16 l1, u8 address)
+{
+ u32 val;
+
+ pci_write_config_dword(iommu->dev, 0xf8, (address | l1 << 16));
+ pci_read_config_dword(iommu->dev, 0xfc, &val);
+ return val;
+}
+
+static void iommu_write_l1(struct amd_iommu *iommu, u16 l1, u8 address, u32 val)
+{
+ pci_write_config_dword(iommu->dev, 0xf8, (address | l1 << 16 | 1 << 31));
+ pci_write_config_dword(iommu->dev, 0xfc, val);
+ pci_write_config_dword(iommu->dev, 0xf8, (address | l1 << 16));
+}
+
+static u32 iommu_read_l2(struct amd_iommu *iommu, u8 address)
+{
+ u32 val;
+
+ pci_write_config_dword(iommu->dev, 0xf0, address);
+ pci_read_config_dword(iommu->dev, 0xf4, &val);
+ return val;
+}
+
+static void iommu_write_l2(struct amd_iommu *iommu, u8 address, u32 val)
+{
+ pci_write_config_dword(iommu->dev, 0xf0, (address | 1 << 8));
+ pci_write_config_dword(iommu->dev, 0xf4, val);
+}
+
/****************************************************************************
*
* AMD IOMMU MMIO register space handling functions
@@ -619,6 +652,7 @@
{
int cap_ptr = iommu->cap_ptr;
u32 range, misc;
+ int i, j;
pci_read_config_dword(iommu->dev, cap_ptr + MMIO_CAP_HDR_OFFSET,
&iommu->cap);
@@ -633,12 +667,29 @@
MMIO_GET_LD(range));
iommu->evt_msi_num = MMIO_MSI_NUM(misc);
- if (is_rd890_iommu(iommu->dev)) {
- pci_read_config_dword(iommu->dev, 0xf0, &iommu->cache_cfg[0]);
- pci_read_config_dword(iommu->dev, 0xf4, &iommu->cache_cfg[1]);
- pci_read_config_dword(iommu->dev, 0xf8, &iommu->cache_cfg[2]);
- pci_read_config_dword(iommu->dev, 0xfc, &iommu->cache_cfg[3]);
- }
+ if (!is_rd890_iommu(iommu->dev))
+ return;
+
+ /*
+ * Some rd890 systems may not be fully reconfigured by the BIOS, so
+ * it's necessary for us to store this information so it can be
+ * reprogrammed on resume
+ */
+
+ pci_read_config_dword(iommu->dev, iommu->cap_ptr + 4,
+ &iommu->stored_addr_lo);
+ pci_read_config_dword(iommu->dev, iommu->cap_ptr + 8,
+ &iommu->stored_addr_hi);
+
+ /* Low bit locks writes to configuration space */
+ iommu->stored_addr_lo &= ~1;
+
+ for (i = 0; i < 6; i++)
+ for (j = 0; j < 0x12; j++)
+ iommu->stored_l1[i][j] = iommu_read_l1(iommu, i, j);
+
+ for (i = 0; i < 0x83; i++)
+ iommu->stored_l2[i] = iommu_read_l2(iommu, i);
}
/*
@@ -1127,14 +1178,53 @@
iommu_feature_enable(iommu, CONTROL_COHERENT_EN);
}
-static void iommu_apply_quirks(struct amd_iommu *iommu)
+static void iommu_apply_resume_quirks(struct amd_iommu *iommu)
{
- if (is_rd890_iommu(iommu->dev)) {
- pci_write_config_dword(iommu->dev, 0xf0, iommu->cache_cfg[0]);
- pci_write_config_dword(iommu->dev, 0xf4, iommu->cache_cfg[1]);
- pci_write_config_dword(iommu->dev, 0xf8, iommu->cache_cfg[2]);
- pci_write_config_dword(iommu->dev, 0xfc, iommu->cache_cfg[3]);
- }
+ int i, j;
+ u32 ioc_feature_control;
+ struct pci_dev *pdev = NULL;
+
+ /* RD890 BIOSes may not have completely reconfigured the iommu */
+ if (!is_rd890_iommu(iommu->dev))
+ return;
+
+ /*
+ * First, we need to ensure that the iommu is enabled. This is
+ * controlled by a register in the northbridge
+ */
+ pdev = pci_get_bus_and_slot(iommu->dev->bus->number, PCI_DEVFN(0, 0));
+
+ if (!pdev)
+ return;
+
+ /* Select Northbridge indirect register 0x75 and enable writing */
+ pci_write_config_dword(pdev, 0x60, 0x75 | (1 << 7));
+ pci_read_config_dword(pdev, 0x64, &ioc_feature_control);
+
+ /* Enable the iommu */
+ if (!(ioc_feature_control & 0x1))
+ pci_write_config_dword(pdev, 0x64, ioc_feature_control | 1);
+
+ pci_dev_put(pdev);
+
+ /* Restore the iommu BAR */
+ pci_write_config_dword(iommu->dev, iommu->cap_ptr + 4,
+ iommu->stored_addr_lo);
+ pci_write_config_dword(iommu->dev, iommu->cap_ptr + 8,
+ iommu->stored_addr_hi);
+
+ /* Restore the l1 indirect regs for each of the 6 l1s */
+ for (i = 0; i < 6; i++)
+ for (j = 0; j < 0x12; j++)
+ iommu_write_l1(iommu, i, j, iommu->stored_l1[i][j]);
+
+ /* Restore the l2 indirect regs */
+ for (i = 0; i < 0x83; i++)
+ iommu_write_l2(iommu, i, iommu->stored_l2[i]);
+
+ /* Lock PCI setup registers */
+ pci_write_config_dword(iommu->dev, iommu->cap_ptr + 4,
+ iommu->stored_addr_lo | 1);
}
/*
@@ -1147,7 +1237,6 @@
for_each_iommu(iommu) {
iommu_disable(iommu);
- iommu_apply_quirks(iommu);
iommu_init_flags(iommu);
iommu_set_device_table(iommu);
iommu_enable_command_buffer(iommu);
@@ -1173,6 +1262,11 @@
static int amd_iommu_resume(struct sys_device *dev)
{
+ struct amd_iommu *iommu;
+
+ for_each_iommu(iommu)
+ iommu_apply_resume_quirks(iommu);
+
/* re-load the hardware */
enable_iommus();