[PATCH v2 2/3] scsi: ufs: Exynos: Fix the maximum segment size

[Bart Van Assche <bvanassche@acm.org>]

Prepare for enabling DMA clustering and also for supporting
PAGE_SIZE != 4096 by declaring explicitly that the maximum segment
size is 4096 bytes for Exynos UFS host controllers. Add this code
in exynos_ufs_hce_enable_notify() such that it happens after
scsi_host_alloc() and before __scsi_init_queue() is called by the
LUN scanning code.

Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Kiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/ufs/host/ufs-exynos.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/ufs/host/ufs-exynos.c b/drivers/ufs/host/ufs-exynos.c
index 3cdac89a28b8..7c985fc38db1 100644
--- a/drivers/ufs/host/ufs-exynos.c
+++ b/drivers/ufs/host/ufs-exynos.c
@@ -1300,6 +1300,14 @@ static int exynos_ufs_hce_enable_notify(struct ufs_hba *hba,
 
 	switch (status) {
 	case PRE_CHANGE:
+		/*
+		 * The maximum segment size must be set after scsi_host_alloc()
+		 * has been called and before LUN scanning starts
+		 * (ufshcd_async_scan()). Note: this callback may also be called
+		 * from other functions than ufshcd_init().
+		 */
+		hba->host->max_segment_size = 4096;
+
 		if (ufs->drv_data->pre_hce_enable) {
 			ret = ufs->drv_data->pre_hce_enable(ufs);
 			if (ret)