openwrt/target/linux/bcm27xx/patches-4.19/950-0327-bcm2835-sdhost-Allow-for-sg-entries-that-cross-pages.patch

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From 44db7882be675cdf2d89741af5bbeba41b3e25af Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Wed, 13 Mar 2019 14:19:11 +0000
Subject: [PATCH] bcm2835-sdhost: Allow for sg entries that cross pages
The dma_complete handling code calculates a virtual address for a page
then adds an offset, but if the offset is more than a page and HIGHMEM
is in use then the summed address could be in an unmapped (or just
incorrect) page.
The upstream SDHOST driver allows for this possibility - copy the code
that does so.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
drivers/mmc/host/bcm2835-sdhost.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/mmc/host/bcm2835-sdhost.c
+++ b/drivers/mmc/host/bcm2835-sdhost.c
@@ -543,6 +543,11 @@ static void bcm2835_sdhost_dma_complete(
void *page;
u32 *buf;
+ if (host->drain_offset & PAGE_MASK) {
+ host->drain_page += host->drain_offset >> PAGE_SHIFT;
+ host->drain_offset &= ~PAGE_MASK;
+ }
+
page = kmap_atomic(host->drain_page);
buf = page + host->drain_offset;