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.

Change-Id: I8df66c87d6a6105da556d327d4cc5148e444d20e Signed-off-by: Aaron Williams awilliams@marvell.com --- drivers/nvme/nvme.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c index 7008a54a6d..c94a6d0654 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; @@ -115,6 +118,7 @@ static int nvme_setup_prps(struct nvme_dev *dev, u64 *prp2, nprps--; } *prp2 = (ulong)dev->prp_pool; + flush_dcache_range(*prp2, *prp2 + (num_pages * page_size));

return 0; } @@ -791,7 +795,7 @@ 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