nvme: fix dcache invalidation range in identify command

When the identify buffer crosses a page boundary, PRP2 is used
and dma_addr is advanced to the second page:

    dma_addr += (page_size - offset);

The subsequent invalidate_dcache_range() calls then use the
modified dma_addr instead of the original buffer start address.

As a result, the beginning of the identify buffer is not
invalidated and the invalidation range extends past the end of
the buffer.

Fix this by preserving the original DMA buffer address for cache
invalidation.

Suggested-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Prashant Kamble <prashant.kamble223@gmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260524100625.11135-1-prashant.kamble223@gmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c
index 0631b190b9785c16b6c588c25b190ae3e2021d94..da7dad9f52b8abc13a384cd58c68402dc126e7a9 100644 (file)
--- a/drivers/nvme/nvme.c
+++ b/drivers/nvme/nvme.c
@@ -27,6 +27,23 @@
 #define IO_TIMEOUT             30
 #define MAX_PRP_POOL           512
 
+/**
+ * nvme_invalidate_cache_aligned() - invalidate cache with proper alignment
+ *
+ * Aligns cache invalidation to cacheline boundaries to ensure correct
+ * behavior even when the DMA buffer is not aligned to page boundaries.
+ *
+ * @addr:      The start address of the buffer
+ * @length:    The length of the buffer in bytes
+ */
+static inline void nvme_invalidate_cache_aligned(uintptr_t addr, int length)
+{
+       uintptr_t start_addr = addr & ~(ARCH_DMA_MINALIGN - 1);
+       uintptr_t end_addr = ALIGN(addr + length, ARCH_DMA_MINALIGN);
+
+       invalidate_dcache_range(start_addr, end_addr);
+}
+
 static int nvme_wait_csts(struct nvme_dev *dev, u32 mask, u32 val)
 {
        int timeout;
@@ -456,6 +473,7 @@ int nvme_identify(struct nvme_dev *dev, unsigned nsid,
        u32 page_size = dev->page_size;
        int offset = dma_addr & (page_size - 1);
        int length = sizeof(struct nvme_id_ctrl);
+       dma_addr_t orig_dma_addr = dma_addr;
        int ret;
 
        memset(&c, 0, sizeof(c));
@@ -473,13 +491,13 @@ int nvme_identify(struct nvme_dev *dev, unsigned nsid,
 
        c.identify.cns = cpu_to_le32(cns);
 
-       invalidate_dcache_range(dma_addr,
-                               dma_addr + sizeof(struct nvme_id_ctrl));
+       nvme_invalidate_cache_aligned((uintptr_t)orig_dma_addr,
+                                     sizeof(struct nvme_id_ctrl));
 
        ret = nvme_submit_admin_cmd(dev, &c, NULL);
        if (!ret)
-               invalidate_dcache_range(dma_addr,
-                                       dma_addr + sizeof(struct nvme_id_ctrl));
+               nvme_invalidate_cache_aligned((uintptr_t)orig_dma_addr,
+                                             sizeof(struct nvme_id_ctrl));
 
        return ret;
 }