| Message ID | 20190502084748.22518-1-faiz_abbas@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: dts: am57xx-idk: Remove support for voltage switching for SD card | expand |
* Faiz Abbas <faiz_abbas@ti.com> [190502 01:48]: > 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). This sounds a bit urgent, does it also need a stable tag or is it safe to apply against any earlier kernels? Regards, Tony > Signed-off-by: Faiz Abbas <faiz_abbas@ti.com> > --- > arch/arm/boot/dts/am57xx-idk-common.dtsi | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm/boot/dts/am57xx-idk-common.dtsi b/arch/arm/boot/dts/am57xx-idk-common.dtsi > index f7bd26458915..42e433da79ec 100644 > --- a/arch/arm/boot/dts/am57xx-idk-common.dtsi > +++ b/arch/arm/boot/dts/am57xx-idk-common.dtsi > @@ -420,6 +420,7 @@ > vqmmc-supply = <&ldo1_reg>; > bus-width = <4>; > cd-gpios = <&gpio6 27 GPIO_ACTIVE_LOW>; /* gpio 219 */ > + no-1-8-v; > }; > > &mmc2 { > -- > 2.19.2 >
Hi Tony, On 02/05/19 7:50 PM, Tony Lindgren wrote: > * Faiz Abbas <faiz_abbas@ti.com> [190502 01:48]: >> 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). > > This sounds a bit urgent, does it also need a stable tag or is > it safe to apply against any earlier kernels? > This should be good to apply on any previous releases. Thanks, Faiz
* Faiz Abbas <a0230074@ti.com> [190502 14:30]: > Hi Tony, > > On 02/05/19 7:50 PM, Tony Lindgren wrote: > > * Faiz Abbas <faiz_abbas@ti.com> [190502 01:48]: > >> 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). > > > > This sounds a bit urgent, does it also need a stable tag or is > > it safe to apply against any earlier kernels? > > > > This should be good to apply on any previous releases. OK applying both your MMC patches into fixes today. Thanks, Tony
diff --git a/arch/arm/boot/dts/am57xx-idk-common.dtsi b/arch/arm/boot/dts/am57xx-idk-common.dtsi index f7bd26458915..42e433da79ec 100644 --- a/arch/arm/boot/dts/am57xx-idk-common.dtsi +++ b/arch/arm/boot/dts/am57xx-idk-common.dtsi @@ -420,6 +420,7 @@ vqmmc-supply = <&ldo1_reg>; bus-width = <4>; cd-gpios = <&gpio6 27 GPIO_ACTIVE_LOW>; /* gpio 219 */ + no-1-8-v; }; &mmc2 {
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). Signed-off-by: Faiz Abbas <faiz_abbas@ti.com> --- arch/arm/boot/dts/am57xx-idk-common.dtsi | 1 + 1 file changed, 1 insertion(+)