Subject: [PATCH 21/22] mmc: wbsd: Use dma_alloc_noncoherent() for dma buffer

From: Baoquan He <[email-masked]>
Date: Sat, 19 Feb 2022 08:52:20 +0800

Use dma_alloc_noncoherent() instead to get the DMA buffer.

[ [email-masked]: Only keep label free.

  Remove unnecessary alignment checks. it's guaranteed by DMA API.
  Just use GFP_KERNEL as it's called in sleepable context.

  Specify its dma capability using  dma_set_mask_and_coherent() ]

Signed-off-by: Baoquan He <[email-masked]>
Signed-off-by: Hyeonggon Yoo <[email-masked]>
Cc: Pierre Ossman <[email-masked]>
Cc: Ulf Hansson <[email-masked]>
Cc: [email-masked]
---
 drivers/mmc/host/wbsd.c | 45 +++++++++--------------------------------
 1 file changed, 9 insertions(+), 36 deletions(-)

diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
index 67ecd342fe5f..50b0197583c7 100644
--- a/drivers/mmc/host/wbsd.c
+++ b/drivers/mmc/host/wbsd.c
@@ -1366,55 +1366,28 @@ static void wbsd_request_dma(struct wbsd_host *host, int dma)
 	if (request_dma(dma, DRIVER_NAME))
 		goto err;
 
+	dma_set_mask_and_coherent(mmc_dev(host->mmc), DMA_BIT_MASK(24));
+
 	/*
 	 * We need to allocate a special buffer in
 	 * order for ISA to be able to DMA to it.
 	 */
-	host->dma_buffer = kmalloc(WBSD_DMA_SIZE,
-		GFP_NOIO | GFP_DMA | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+	host->dma_buffer = dma_alloc_noncoherent(mmc_dev(host->mmc),
+					WBSD_DMA_SIZE, &host->dma_addr,
+					DMA_BIDIRECTIONAL,
+					GFP_KERNEL);
 	if (!host->dma_buffer)
 		goto free;
 
-	/*
-	 * Translate the address to a physical address.
-	 */
-	host->dma_addr = dma_map_single(mmc_dev(host->mmc), host->dma_buffer,
-		WBSD_DMA_SIZE, DMA_BIDIRECTIONAL);
-	if (dma_mapping_error(mmc_dev(host->mmc), host->dma_addr))
-		goto kfree;
-
-	/*
-	 * ISA DMA must be aligned on a 64k basis.
-	 */
-	if ((host->dma_addr & 0xffff) != 0)
-		goto unmap;
-	/*
-	 * ISA cannot access memory above 16 MB.
-	 */
-	else if (host->dma_addr >= 0x1000000)
-		goto unmap;
-
 	host->dma = dma;
 
 	return;
 
-unmap:
-	/*
-	 * If we've gotten here then there is some kind of alignment bug
-	 */
-	BUG_ON(1);
-
-	dma_unmap_single(mmc_dev(host->mmc), host->dma_addr,
-		WBSD_DMA_SIZE, DMA_BIDIRECTIONAL);
-	host->dma_addr = 0;
-
-kfree:
-	kfree(host->dma_buffer);
-	host->dma_buffer = NULL;
-
 free:
+	dma_free_noncoherent(mmc_dev(host->mmc), WBSD_DMA_SIZE, host->dma_buffer,
+			     host->dma_addr, DMA_BIDIRECTIONAL);
+	host->dma_buffer = NULL;
 	free_dma(dma);
-
 err:
 	pr_warn(DRIVER_NAME ": Unable to allocate DMA %d - falling back on FIFO\n",
 		dma);
-- 
2.17.2