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 <kis...@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhib...@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.
OK. i'll change it in v2.
+ 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.
I need to figure this out. I forgot to mention it, but all this code is
based on the work of Kishon Vijay Abraham who did the hs200 support for
the ti u-boot tree.
Kishon,
can you point to the relevant part of the spec ?
+ 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);
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