From: Mika Westerberg mika.westerberg@linux.intel.com
[ Upstream commit 17a0f3acdc6ec8b89ad40f6e22165a4beee25663 ]
Before sending a MSI the hardware writes information pertinent to the interrupt cause to a memory location pointed by SMTICL register. This memory holds three double words where the least significant bit tells whether the interrupt cause of master/target/error is valid. The driver does not use this but we need to set it up because otherwise it will perform DMA write to the default address (0) and this will cause an IOMMU fault such as below:
DMAR: DRHD: handling fault status reg 2 DMAR: [DMA Write] Request device [00:12.0] PASID ffffffff fault addr 0 [fault reason 05] PTE Write access is not set
To prevent this from happening, provide a proper DMA buffer for this that then gets mapped by the IOMMU accordingly.
Signed-off-by: Mika Westerberg mika.westerberg@linux.intel.com Reviewed-by: From: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-ismt.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c index a35a27c320e7..3d2d92640651 100644 --- a/drivers/i2c/busses/i2c-ismt.c +++ b/drivers/i2c/busses/i2c-ismt.c @@ -82,6 +82,7 @@
#define ISMT_DESC_ENTRIES 2 /* number of descriptor entries */ #define ISMT_MAX_RETRIES 3 /* number of SMBus retries to attempt */ +#define ISMT_LOG_ENTRIES 3 /* number of interrupt cause log entries */
/* Hardware Descriptor Constants - Control Field */ #define ISMT_DESC_CWRL 0x01 /* Command/Write Length */ @@ -175,6 +176,8 @@ struct ismt_priv { u8 head; /* ring buffer head pointer */ struct completion cmp; /* interrupt completion */ u8 buffer[I2C_SMBUS_BLOCK_MAX + 16]; /* temp R/W data buffer */ + dma_addr_t log_dma; + u32 *log; };
static const struct pci_device_id ismt_ids[] = { @@ -409,6 +412,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, memset(desc, 0, sizeof(struct ismt_desc)); desc->tgtaddr_rw = ISMT_DESC_ADDR_RW(addr, read_write);
+ /* Always clear the log entries */ + memset(priv->log, 0, ISMT_LOG_ENTRIES * sizeof(u32)); + /* Initialize common control bits */ if (likely(pci_dev_msi_enabled(priv->pci_dev))) desc->control = ISMT_DESC_INT | ISMT_DESC_FAIR; @@ -693,6 +699,8 @@ static void ismt_hw_init(struct ismt_priv *priv) /* initialize the Master Descriptor Base Address (MDBA) */ writeq(priv->io_rng_dma, priv->smba + ISMT_MSTR_MDBA);
+ writeq(priv->log_dma, priv->smba + ISMT_GR_SMTICL); + /* initialize the Master Control Register (MCTRL) */ writel(ISMT_MCTRL_MEIE, priv->smba + ISMT_MSTR_MCTRL);
@@ -780,6 +788,12 @@ static int ismt_dev_init(struct ismt_priv *priv) priv->head = 0; init_completion(&priv->cmp);
+ priv->log = dmam_alloc_coherent(&priv->pci_dev->dev, + ISMT_LOG_ENTRIES * sizeof(u32), + &priv->log_dma, GFP_KERNEL); + if (!priv->log) + return -ENOMEM; + return 0; }