From 3d7c194b7c9ad414264935ad4f943a6ce285ebb1 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@intel.com>
Date: Mon, 15 Nov 2021 10:23:45 +0200
Subject: [PATCH] mmc: sdhci: Fix ADMA for PAGE_SIZE >= 64KiB
Git-commit: 3d7c194b7c9ad414264935ad4f943a6ce285ebb1
Patch-mainline: v5.16-rc3
References: git-fixes

The block layer forces a minimum segment size of PAGE_SIZE, so a segment
can be too big for the ADMA table, if PAGE_SIZE >= 64KiB. Fix by writing
multiple descriptors, noting that the ADMA table is sized for 4KiB chunks
anyway, so it will be big enough.

Reported-and-tested-by: Bough Chen <haibo.chen@nxp.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211115082345.802238-1-adrian.hunter@intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mmc/host/sdhci.c |   21 ++++++++++++++++++---
 drivers/mmc/host/sdhci.h |    4 +++-
 2 files changed, 21 insertions(+), 4 deletions(-)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -771,7 +771,19 @@ static void sdhci_adma_table_pre(struct
 			len -= offset;
 		}
 
-		BUG_ON(len > 65536);
+		/*
+		 * The block layer forces a minimum segment size of PAGE_SIZE,
+		 * so 'len' can be too big here if PAGE_SIZE >= 64KiB. Write
+		 * multiple descriptors, noting that the ADMA table is sized
+		 * for 4KiB chunks anyway, so it will be big enough.
+		 */
+		while (len > host->max_adma) {
+			int n = 32 * 1024; /* 32KiB*/
+
+			__sdhci_adma_write_desc(host, &desc, addr, n, ADMA2_TRAN_VALID);
+			addr += n;
+			len -= n;
+		}
 
 		/* tran, valid */
 		if (len)
@@ -3946,6 +3958,7 @@ struct sdhci_host *sdhci_alloc_host(stru
 	 * descriptor for each segment, plus 1 for a nop end descriptor.
 	 */
 	host->adma_table_cnt = SDHCI_MAX_SEGS * 2 + 1;
+	host->max_adma = 65536;
 
 	return host;
 }
@@ -4609,10 +4622,12 @@ int sdhci_setup_host(struct sdhci_host *
 	 * be larger than 64 KiB though.
 	 */
 	if (host->flags & SDHCI_USE_ADMA) {
-		if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC)
+		if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC) {
+			host->max_adma = 65532; /* 32-bit alignment */
 			mmc->max_seg_size = 65535;
-		else
+		} else {
 			mmc->max_seg_size = 65536;
+		}
 	} else {
 		mmc->max_seg_size = mmc->max_req_size;
 	}
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -340,7 +340,8 @@ struct sdhci_adma2_64_desc {
 
 /*
  * Maximum segments assuming a 512KiB maximum requisition size and a minimum
- * 4KiB page size.
+ * 4KiB page size. Note this also allows enough for multiple descriptors in
+ * case of PAGE_SIZE >= 64KiB.
  */
 #define SDHCI_MAX_SEGS		128
 
@@ -542,6 +543,7 @@ struct sdhci_host {
 	unsigned int blocks;	/* remaining PIO blocks */
 
 	int sg_count;		/* Mapped sg entries */
+	int max_adma;		/* Max. length in ADMA descriptor */
 
 	void *adma_table;	/* ADMA descriptor table */
 	void *align_buffer;	/* Bounce buffer */