From: Ahmad Fatoum <a.fatoum@pengutronix.de> To: barebox@lists.infradead.org Cc: mgr@pengutronix.de, ore@pengutronix.de, Ahmad Fatoum <a.fatoum@pengutronix.de> Subject: [PATCH 3/3] ARM: at91: xload-mmc: add prominent note about PBL MMC limitation Date: Wed, 2 Jun 2021 12:25:24 +0200 Message-ID: <20210602102524.20034-3-a.fatoum@pengutronix.de> (raw) In-Reply-To: <20210602102524.20034-1-a.fatoum@pengutronix.de> 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@pengutronix.de> --- 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 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox
next prev parent reply other threads:[~2021-06-02 10:27 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-02 10:25 [PATCH 1/3] ARM: at91: microchip-ksz9477-evb: support PBL console Ahmad Fatoum 2021-06-02 10:25 ` [PATCH 2/3] ARM: at91: mmc-xload: allow overriding card capacity Ahmad Fatoum 2021-06-02 10:30 ` Ahmad Fatoum 2021-06-03 5:34 ` Alexander Dahl 2021-06-03 6:28 ` Ahmad Fatoum 2021-06-03 6:53 ` Alexander Dahl 2021-06-03 7:01 ` Ahmad Fatoum 2021-06-02 10:25 ` Ahmad Fatoum [this message] 2021-06-02 10:29 ` [PATCH 1/3] ARM: at91: microchip-ksz9477-evb: support PBL console Ahmad Fatoum
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