Hi Jaehoon,
On 25/05/2017 14:35, Jaehoon Chung wrote:
On 05/13/2017 03:16 AM, Jean-Jacques Hiblot wrote:
mmc/sd specification requires vdd to be disabled for 1 ms and then enabled again during power cycle. Add a function in mmc core to perform power cycle and set the io signal to it's initial state.
Signed-off-by: Kishon Vijay Abraham I kishon@ti.com Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com
drivers/mmc/mmc.c | 50 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 9 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index d40a22b..032260b 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -30,6 +30,7 @@ static const unsigned int sd_au_size[] = { SZ_16M / 512, (SZ_16M + SZ_8M) / 512, SZ_32M / 512, SZ_64M / 512, }; static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage); +static void mmc_power_cycle(struct mmc *mmc);
#if CONFIG_IS_ENABLED(MMC_TINY) static struct mmc mmc_static; @@ -1915,6 +1916,45 @@ static int mmc_power_init(struct mmc *mmc) return 0; }
+static void mmc_set_initial_state(struct mmc *mmc) +{
- int err;
- /* First try to set 3.3V. If it fails set to 1.8V */
- err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
- if (err != 0)
err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);- if (err != 0)
printf("failed to set signal voltage\n");- mmc_set_bus_width(mmc, 1);
- mmc_set_clock(mmc, 1);
- mmc_select_mode(mmc, MMC_LEGACY);
+}
+static void mmc_power_up(struct mmc *mmc) +{
- mmc_set_initial_state(mmc);
- mmc_set_vdd(mmc, true);
mmc_set_vdd has the return value..but there are no usage anywhere.. if this is correct, mmc_set_vdd can be *void* type.
- udelay(10000);
+}
+static void mmc_power_off(struct mmc *mmc) +{
- mmc_set_vdd(mmc, false);
+}
+static void mmc_power_cycle(struct mmc *mmc) +{
- mmc_power_off(mmc);
- /*
* SD spec recommends at least 1ms of delay. Let's wait for 2ms* to be on the safer side.*/Could you put the SD spec version and about which part...? I didn't find the 2ms so..i want to see the spec about 2ms.
The requirement for 1ms is found in the simplified specifications "Part1_Physical_Layer_Simplified_Specification_Ver6.00.pdf":
[...] 6.4.1.5 Power Down and Power Cycle When the host shuts down the power, the card VDD shall be lowered to less than 0.5Volt for a minimum period of 1ms. [....]
2ms is just to be on the safer side.
JJ
- udelay(2000);
- mmc_power_up(mmc);
+}
- int mmc_start_init(struct mmc *mmc) { bool no_card;
@@ -1952,16 +1992,8 @@ int mmc_start_init(struct mmc *mmc) return err; #endif mmc->ddr_mode = 0;
mmc_set_vdd(mmc, true);
/* First try to set 3.3V. If it fails set to 1.8V */
err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
if (err != 0)
err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);if (err != 0)
printf("failed to set signal voltage\n");mmc_set_bus_width(mmc, 1);
mmc_set_clock(mmc, 1);
mmc_power_cycle(mmc);
/* Reset the Card */ err = mmc_go_idle(mmc);