[PATCH v2 36/38] cxlflash: Register for translation errors

Uma Krishnan
2018-02-26T22:24:49Z

While enabling a context on the link, a predefined callback can be
registered with the OCXL provider services to be notified on translation
errors. These errors can in turn be passed back to the user on a read
operation.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
---
drivers/scsi/cxlflash/ocxl_hw.c | 31 +++++++++++++++++++++++++++++--
drivers/scsi/cxlflash/ocxl_hw.h | 4 ++++
2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c
index d707e4c..9356672 100644
--- a/drivers/scsi/cxlflash/ocxl_hw.c
+++ b/drivers/scsi/cxlflash/ocxl_hw.c
@@ -335,6 +335,25 @@ static u64 ocxlflash_get_irq_objhndl(void *ctx_cookie, int irq)
}

/**
+ * ocxlflash_xsl_fault() - callback when translation error is triggered
+ * @data: Private data provided at callback registration, the context.
+ * @addr: Address that triggered the error.
+ * @dsisr: Value of dsisr register.
+ */
+static void ocxlflash_xsl_fault(void *data, u64 addr, u64 dsisr)
+{
+ struct ocxlflash_context *ctx = data;
+
+ spin_lock(&ctx->slock);
+ ctx->fault_addr = addr;
+ ctx->fault_dsisr = dsisr;
+ ctx->pending_fault = true;
+ spin_unlock(&ctx->slock);
+
+ wake_up_all(&ctx->wq);
+}
+
+/**
* start_context() - local routine to start a context
* @ctx: Adapter context to be started.
*
@@ -378,7 +397,8 @@ static int start_context(struct ocxlflash_context *ctx)
mm = current->mm;
}

- rc = ocxl_link_add_pe(link_token, ctx->pe, pid, 0, 0, mm, NULL, NULL);
+ rc = ocxl_link_add_pe(link_token, ctx->pe, pid, 0, 0, mm,
+ ocxlflash_xsl_fault, ctx);
if (unlikely(rc)) {
dev_err(dev, "%s: ocxl_link_add_pe failed rc=%d\n",
__func__, rc);
@@ -512,6 +532,7 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie)
ctx->hw_afu = afu;
ctx->irq_bitmap = 0;
ctx->pending_irq = false;
+ ctx->pending_fault = false;
out:
return ctx;
err2:
@@ -957,7 +978,7 @@ static void *ocxlflash_create_afu(struct pci_dev *pdev)
*/
static inline bool ctx_event_pending(struct ocxlflash_context *ctx)
{
- if (ctx->pending_irq)
+ if (ctx->pending_irq || ctx->pending_fault)
return true;

return false;
@@ -1062,6 +1083,12 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
event.irq.irq = bit + 1;
if (bitmap_empty(&ctx->irq_bitmap, ctx->num_irqs))
ctx->pending_irq = false;
+ } else if (ctx->pending_fault) {
+ event.header.size += sizeof(struct cxl_event_data_storage);
+ event.header.type = CXL_EVENT_DATA_STORAGE;
+ event.fault.addr = ctx->fault_addr;
+ event.fault.dsisr = ctx->fault_dsisr;
+ ctx->pending_fault = false;
}

spin_unlock_irqrestore(&ctx->slock, lock_flags);
diff --git a/drivers/scsi/cxlflash/ocxl_hw.h b/drivers/scsi/cxlflash/ocxl_hw.h
index a4f3b90..eb1c24a 100644
--- a/drivers/scsi/cxlflash/ocxl_hw.h
+++ b/drivers/scsi/cxlflash/ocxl_hw.h
@@ -69,4 +69,8 @@ struct ocxlflash_context {
int num_irqs; /* Number of interrupts */
bool pending_irq; /* Pending interrupt on the context */
ulong irq_bitmap; /* Bits indicating pending irq num */
+
+ u64 fault_addr; /* Address that triggered the fault */
+ u64 fault_dsisr; /* Value of dsisr register at fault */
+ bool pending_fault; /* Pending translation fault */
};
--
2.1.0