When large writes take place I saw a Samsung
EVO 970+ return a status value of 0x13, PRP
Offset Invalid. I tracked this down to the
improper handling of PRP entries. The blocks
the PRP entries are placed in cannot cross a
page boundary and thus should be allocated on
page boundaries. This is how the Linux kernel
driver works.
With this patch, the PRP pool is allocated on
a page boundary and other than the very first
allocation, the pool size is a multiple of
the page size. Each page can hold (4096 / 8) - 1
entries since the last entry must point to the
next page in the pool.
Signed-off-by: Aaron Williams <awilli...@marvell.com>
---
drivers/nvme/nvme.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c
index 7008a54a6d..ae64459edf 100644
--- a/drivers/nvme/nvme.c
+++ b/drivers/nvme/nvme.c
@@ -75,6 +75,8 @@ static int nvme_setup_prps(struct nvme_dev *dev, u64 *prp2,
int length = total_len;
int i, nprps;
length -= (page_size - offset);
+ u32 prps_per_page = (page_size >> 3) - 1;
+ u32 num_pages;
if (length <= 0) {
*prp2 = 0;
@@ -90,15 +92,16 @@ static int nvme_setup_prps(struct nvme_dev *dev, u64 *prp2,
}
nprps = DIV_ROUND_UP(length, page_size);
+ num_pages = (nprps + prps_per_page - 1) / prps_per_page;
if (nprps > dev->prp_entry_num) {
free(dev->prp_pool);
- dev->prp_pool = malloc(nprps << 3);
+ dev->prp_pool = memalign(page_size, num_pages * page_size);
if (!dev->prp_pool) {
printf("Error: malloc prp_pool fail\n");
return -ENOMEM;
}
- dev->prp_entry_num = nprps;
+ dev->prp_entry_num = ((page_size >> 3) - 1) * num_pages;
}
prp_pool = dev->prp_pool;
@@ -791,7 +794,7 @@ static int nvme_probe(struct udevice *udev)
}
memset(ndev->queues, 0, NVME_Q_NUM * sizeof(struct nvme_queue *));
- ndev->prp_pool = malloc(MAX_PRP_POOL);
+ ndev->prp_pool = memalign(1 << 12, MAX_PRP_POOL);
if (!ndev->prp_pool) {
ret = -ENOMEM;
printf("Error: %s: Out of memory!\n", udev->name);
--
2.16.4
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