bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0914-mmc-block-Don-t-do-single-sector-reads-during-recove.patch b/target/linux/bcm27xx/patches-5.15/950-0914-mmc-block-Don-t-do-single-sector-reads-during-recove.patch
new file mode 100644
index 0000000000..da9c428efb
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0914-mmc-block-Don-t-do-single-sector-reads-during-recove.patch
@@ -0,0 +1,38 @@
+From b70da899940777d92338d8f83f7a6236818ad08a Mon Sep 17 00:00:00 2001
+From: Jonathan Bell <jonathan@raspberrypi.com>
+Date: Mon, 16 May 2022 10:28:27 +0100
+Subject: [PATCH] mmc: block: Don't do single-sector reads during
+ recovery
+
+See https://github.com/raspberrypi/linux/issues/5019
+
+If an SD card has degraded performance such that IO operations time out
+then the MMC block layer will leak SG DMA mappings in the swiotlb during
+recovery. It retries the same SG and this causes the leak, as it is
+mapped twice - once in sdhci_pre_req() and again during single-block
+reads in sdhci_prepare_data().
+
+Resetting the card (including power-cycling if a regulator for vmmc is
+present) ought to be enough to recover a stuck state, so for now don't
+try single-block reads in the recovery path.
+
+Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
+---
+ drivers/mmc/core/block.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+--- a/drivers/mmc/core/block.c
++++ b/drivers/mmc/core/block.c
+@@ -1871,7 +1871,11 @@ static void mmc_blk_mq_rw_recovery(struc
+ 	}
+ 
+ 	/* FIXME: Missing single sector read for large sector size */
+-	if (!mmc_large_sector(card) && rq_data_dir(req) == READ &&
++	/*
++	 * XXX: don't do single-sector reads, as it leaks a SG DMA
++	 * mapping when reusing the still-pending req.
++	 */
++	if (0 && !mmc_large_sector(card) && rq_data_dir(req) == READ &&
+ 	    brq->data.blocks > 1) {
+ 		/* Read one sector at a time */
+ 		mmc_blk_read_single(mq, req);