Merge tag 'mmc-v4.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc

Pull MMC fixes from Ulf Hansson:
 "A couple of MMC host fixes intended for v4.14-rc8:

   - renesas_sdhi: fix kernel panic
   - tmio: fix swiotlb buffer is full"

* tag 'mmc-v4.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: renesas_sdhi: fix kernel panic in _internal_dmac.c
  mmc: tmio: fix swiotlb buffer is full

drivers/mmc/host/renesas_sdhi_internal_dmac.c

@@ -146,11 +146,8 @@ renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
 	WARN_ON(host->sg_len > 1);
 
 	/* This DMAC cannot handle if buffer is not 8-bytes alignment */
-	if (!IS_ALIGNED(sg->offset, 8)) {
-		host->force_pio = true;
-		renesas_sdhi_internal_dmac_enable_dma(host, false);
-		return;
-	}
+	if (!IS_ALIGNED(sg->offset, 8))
+		goto force_pio;
 
 	if (data->flags & MMC_DATA_READ) {
 		dtran_mode |= DTRAN_MODE_CH_NUM_CH1;
@@ -163,8 +160,8 @@ renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
 	}
 
 	ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, dir);
-	if (ret < 0)
-		return;
+	if (ret == 0)
+		goto force_pio;
 
 	renesas_sdhi_internal_dmac_enable_dma(host, true);
 
@@ -176,6 +173,12 @@ renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
 					    dtran_mode);
 	renesas_sdhi_internal_dmac_dm_write(host, DM_DTRAN_ADDR,
 					    sg->dma_address);
+
+	return;
+
+force_pio:
+	host->force_pio = true;
+	renesas_sdhi_internal_dmac_enable_dma(host, false);
 }
 
 static void renesas_sdhi_internal_dmac_issue_tasklet_fn(unsigned long arg)

drivers/mmc/host/tmio_mmc_core.c

@@ -47,6 +47,7 @@
 #include <linux/mmc/sdio.h>
 #include <linux/scatterlist.h>
 #include <linux/spinlock.h>
+#include <linux/swiotlb.h>
 #include <linux/workqueue.h>
 
 #include "tmio_mmc.h"
@@ -1215,6 +1216,18 @@ int tmio_mmc_host_probe(struct tmio_mmc_host *_host,
 	mmc->max_blk_count = pdata->max_blk_count ? :
 		(PAGE_SIZE / mmc->max_blk_size) * mmc->max_segs;
 	mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
+	/*
+	 * Since swiotlb has memory size limitation, this will calculate
+	 * the maximum size locally (because we don't have any APIs for it now)
+	 * and check the current max_req_size. And then, this will update
+	 * the max_req_size if needed as a workaround.
+	 */
+	if (swiotlb_max_segment()) {
+		unsigned int max_size = (1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+
+		if (mmc->max_req_size > max_size)
+			mmc->max_req_size = max_size;
+	}
 	mmc->max_seg_size = mmc->max_req_size;
 
 	_host->native_hotplug = !(pdata->flags & TMIO_MMC_USE_GPIO_CD ||