From: Faiz Abbas faiz_abbas@ti.com
commit 88a748419b84187fd1da05637b8e5928b04a1e06 upstream.
If UHS speed modes are enabled, a compatible SD card switches down to 1.8V during enumeration. If after this a software reboot/crash takes place and on-chip ROM tries to enumerate the SD card, the difference in IO voltages (host @ 3.3V and card @ 1.8V) may end up damaging the card.
The fix for this is to have support for power cycling the card in hardware (with a PORz/soft-reset line causing a power cycle of the card). Since am571x-, am572x- and am574x-idk don't have this capability, disable voltage switching for these boards.
The major effect of this is that the maximum supported speed mode is now high speed(50 MHz) down from SDR104(200 MHz).
Cc: stable@vger.kernel.org Signed-off-by: Faiz Abbas faiz_abbas@ti.com Signed-off-by: Tony Lindgren tony@atomide.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm/boot/dts/am57xx-idk-common.dtsi | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm/boot/dts/am57xx-idk-common.dtsi +++ b/arch/arm/boot/dts/am57xx-idk-common.dtsi @@ -410,6 +410,7 @@ vqmmc-supply = <&ldo1_reg>; bus-width = <4>; cd-gpios = <&gpio6 27 GPIO_ACTIVE_LOW>; /* gpio 219 */ + no-1-8-v; };
&mmc2 {