[SeaBIOS] Re: [PATCH 2/5] nvme: Add nvme_bounce_xfer() helper function

[Alexander Graf via SeaBIOS]

On 19.01.22 19:45, Kevin O'Connor wrote:

Move bounce buffer processing to a new helper function.

Signed-off-by: Kevin O'Connor <ke...@koconnor.net>

Reviewed-by: Alexander Graf <g...@amazon.com>

Alex

---
  src/hw/nvme.c | 35 +++++++++++++++++++++--------------
  1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/src/hw/nvme.c b/src/hw/nvme.c
index a97501b..fd7c1d0 100644
--- a/src/hw/nvme.c
+++ b/src/hw/nvme.c
@@ -465,6 +465,25 @@ nvme_io_xfer(struct nvme_namespace *ns, u64 lba, void 
*buf, u16 count,
      return count;
  }

+// Transfer up to one page of data using the internal dma bounce buffer
+static int
+nvme_bounce_xfer(struct nvme_namespace *ns, u64 lba, void *buf, u16 count,
+                 int write)
+{
+    u16 const max_blocks = NVME_PAGE_SIZE / ns->block_size;
+    u16 blocks = count < max_blocks ? count : max_blocks;
+
+    if (write)
+        memcpy(ns->dma_buffer, buf, blocks * ns->block_size);
+
+    int res = nvme_io_xfer(ns, lba, ns->dma_buffer, blocks, write);
+
+    if (!write && res >= 0)
+        memcpy(buf, ns->dma_buffer, res * ns->block_size);
+
+    return res;
+}
+
  static void nvme_reset_prpl(struct nvme_namespace *ns)
  {
      ns->prpl_len = 0;
@@ -718,7 +737,6 @@ nvme_scan(void)
  static int
  nvme_cmd_readwrite(struct nvme_namespace *ns, struct disk_op_s *op, int write)
  {
-    u16 const max_blocks = NVME_PAGE_SIZE / ns->block_size;
      u16 i, blocks;

      for (i = 0; i < op->count;) {
@@ -731,21 +749,10 @@ nvme_cmd_readwrite(struct nvme_namespace *ns, struct 
disk_op_s *op, int write)
              if (res < 0)
                  return DISK_RET_EBADTRACK;
          } else {
-            blocks = blocks_remaining < max_blocks ? blocks_remaining
-                                                   : max_blocks;
-
-            if (write) {
-                memcpy(ns->dma_buffer, op_buf, blocks * ns->block_size);
-            }
-
-            int res = nvme_io_xfer(ns, op->lba + i, ns->dma_buffer,
-                                   blocks, write);
+            int res = nvme_bounce_xfer(ns, op->lba + i, op_buf, blocks, write);
              if (res < 0)
                  return DISK_RET_EBADTRACK;
-
-            if (!write) {
-                memcpy(op_buf, ns->dma_buffer, blocks * ns->block_size);
-            }
+            blocks = res;
          }

          i += blocks;
--
2.31.1

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