The PBL driver has an assumption about only being used with
high capacity cards. When using a default capacity card, the sama5d3
MCI controller hang when doing unaligned accesses.
This heuristic could add some support default capacity card support
without risking unaligned accesses:
at91_mci_set_highcapacity(false);
sector0 = read_sector(0);
if (!is_mbr(sector0, &fatsect)
abort();
fatsector1 = read_sector(fatsect);
at91_mci_set_highcapacity(false);
if (is_fat(fatsect))
goto default_cap;
else
goto high_cap;
This, of course, fails if fatsect * 512 on a high capacity card
happens to have a FAT signature. As it's unclear whether supporting
<= 2 GiB is worth the effort, hardcode it in xload-mmc.c and add
a note about the limitation to conserve future debugging effort.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
arch/arm/mach-at91/xload-mmc.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-at91/xload-mmc.c b/arch/arm/mach-at91/xload-mmc.c
index 1b641f3a47ac..89766cf6b910 100644
--- a/arch/arm/mach-at91/xload-mmc.c
+++ b/arch/arm/mach-at91/xload-mmc.c
@@ -76,8 +76,18 @@ void __noreturn sama5d2_sdhci_start_image(u32 r4)
if (ret)
goto out_panic;
- /* TODO: eMMC boot partition handling: they are not FAT-formatted */
+ /*
+ * There seems to be no definitive way to find out whether we are
+ * connected to a default or high capacity card without resetting
+ * the card. The PBL driver assumes however that the card is already
+ * in transfer mode. For now assume all cards to be high capacity.
+ * If support for cards smaller or equal to 2GiB becomes relevant,
+ * this assumption can be revisited.
+ */
+ pr_debug("Assuming high capacity card\n");
+ at91_sdhci_set_highcapacity(&bio, true);
+ /* TODO: eMMC boot partition handling: they are not FAT-formatted */
at91_fat_start_image(&bio, buf, SZ_16M, r4);
out_panic:
@@ -128,6 +138,18 @@ void __noreturn sama5d3_atmci_start_image(u32 boot_src, unsigned int clock,
if (ret)
goto out_panic;
+ /*
+ * There seems to be no definitive way to find out whether we are
+ * connected to a default or high capacity card without resetting
+ * the card. The PBL driver assumes however that the card is already
+ * in transfer mode. For now assume all cards to be high capacity.
+ * If support for cards smaller or equal to 2GiB becomes relevant,
+ * this assumption can be revisited.
+ */
+ pr_debug("Assuming high capacity card\n");
+ at91_mci_set_highcapacity(&bio, true);
+
+ /* TODO: eMMC boot partition handling: they are not FAT-formatted */
at91_fat_start_image(&bio, buf, SZ_16M, boot_src);
out_panic:
--
2.29.2
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