scsi: smartpqi: correct bdma hw bug

Orabug: 26191021, 26447813

add workaround for BDMA hardware bug that can cause
hw to read up to 12 SGL elements (192 bytes) beyond the
last element in the list. This fix avoids IOMMU violations

Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Signed-off-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit e1d213bdc3e359c6c5da8ebbc5b2e87b376e8777)
Signed-off-by: Brian Maly <brian.maly@oracle.com>

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index e30d9d9d3c341a94d6c72503c64588237c910ccc..752bb175e345b01df71503012fa70ab875772642 100644 (file)
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -48,6 +48,8 @@
 #define DRIVER_NAME            "Microsemi PQI Driver (v" DRIVER_VERSION ")"
 #define DRIVER_NAME_SHORT      "smartpqi"
 
+#define PQI_EXTRA_SGL_MEMORY   (12 * sizeof(struct pqi_sg_descriptor))
+
 MODULE_AUTHOR("Microsemi");
 MODULE_DESCRIPTION("Driver for Microsemi Smart Family Controller version "
        DRIVER_VERSION);
@@ -3243,6 +3245,8 @@ static int pqi_alloc_operational_queues(struct pqi_ctrl_info *ctrl_info)
        alloc_length = (size_t)aligned_pointer +
                PQI_QUEUE_ELEMENT_ARRAY_ALIGNMENT;
 
+       alloc_length += PQI_EXTRA_SGL_MEMORY;
+
        ctrl_info->queue_memory_base =
                dma_zalloc_coherent(&ctrl_info->pci_dev->dev,
                        alloc_length,
@@ -4360,7 +4364,8 @@ static void pqi_calculate_io_resources(struct pqi_ctrl_info *ctrl_info)
        max_transfer_size = (max_sg_entries - 1) * PAGE_SIZE;
 
        ctrl_info->sg_chain_buffer_length =
-               max_sg_entries * sizeof(struct pqi_sg_descriptor);
+               (max_sg_entries * sizeof(struct pqi_sg_descriptor)) +
+               PQI_EXTRA_SGL_MEMORY;
        ctrl_info->sg_tablesize = max_sg_entries;
        ctrl_info->max_sectors = max_transfer_size / 512;
 }