According to eMMC/SD/SDIO specs, the VDD (VCC) voltage level must be
maintained during the initialization sequence. If we want/need to tune
the voltage level, a complete power cycle of the card must be executed.
Most host drivers conforms to the specifications by only allowing to
change VDD voltage level at the MMC_POWER_UP state, but some also cares
about MMC_POWER_ON state, which they should'nt. This patch will not
break those drivers, but they could clean up code to better reflect
what is expected from the protocol layer.
A big re-work of the mmc_select_voltage function is done to only change
VDD voltage level if the host supports MMC_CAP2_FULL_PWR_CYCLE.
Otherwise only validation of the host and card ocr mask will be done.
A very nice side-effect of this patch is that we now don't need to
reset the negotiated ocr mask at the mmc_power_off function, since now
it will actually reflect the present voltage level, which safely can be
used at the next power up and re-initialization. Moreover, we then only
need to execute mmc_select_voltage from the attach sequence.
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
drivers/mmc/core/core.c | 31 +++++++++++--------------------
drivers/mmc/core/mmc.c | 1 -
drivers/mmc/core/sd.c | 1 -
drivers/mmc/core/sdio.c | 17 ++---------------
4 files changed, 13 insertions(+), 37 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 4a1e3ca..0d89ccc 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1383,21 +1383,20 @@ u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
int bit;
ocr &= host->ocr_avail;
+ if (!ocr) {
+ dev_warn(mmc_dev(host), "no support for card's volts\n");
+ return 0;
+ }
- bit = ffs(ocr);
- if (bit) {
- bit -= 1;
-
+ if (host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) {
+ bit = ffs(ocr) - 1;
ocr &= 3 << bit;
-
- mmc_host_clk_hold(host);
- host->ios.vdd = bit;
- mmc_set_ios(host);
- mmc_host_clk_release(host);
+ mmc_power_cycle(host, ocr);
} else {
- pr_warning("%s: host doesn't support card's voltages\n",
- mmc_hostname(host));
- ocr = 0;
+ bit = fls(ocr) - 1;
+ ocr &= 3 << bit;
+ if (bit != host->ios.vdd)
+ dev_warn(mmc_dev(host), "exceeding card's volts\n");
}
return ocr;
@@ -1596,14 +1595,6 @@ void mmc_power_off(struct mmc_host *host)
host->ios.clock = 0;
host->ios.vdd = 0;
-
- /*
- * Reset ocr mask to be the highest possible voltage supported for
- * this card. This value will be used at next power up.
- */
- if (host->card)
- host->card->ocr = 1 << (fls(host->ocr_avail) - 1);
-
if (!mmc_host_is_spi(host)) {
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
host->ios.chip_select = MMC_CS_DONTCARE;
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index efc9f6f..9149eab 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1535,7 +1535,6 @@ static int mmc_resume(struct mmc_host *host)
mmc_claim_host(host);
mmc_power_up(host, host->card->ocr);
- mmc_select_voltage(host, host->card->ocr);
err = mmc_init_card(host, host->card->ocr, host->card);
mmc_release_host(host);
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 398065c..53db60a 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1103,7 +1103,6 @@ static int mmc_sd_resume(struct mmc_host *host)
mmc_claim_host(host);
mmc_power_up(host, host->card->ocr);
- mmc_select_voltage(host, host->card->ocr);
err = mmc_sd_init_card(host, host->card->ocr, host->card);
mmc_release_host(host);
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index e0a135a..b7c19e8 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -987,7 +987,6 @@ static int mmc_sdio_resume(struct mmc_host *host)
/* Restore power if needed */
if (!mmc_card_keep_power(host)) {
mmc_power_up(host, host->card->ocr);
- mmc_select_voltage(host, host->card->ocr);
/*
* Tell runtime PM core we just powered up the card,
* since it still believes the card is powered off.
@@ -1045,7 +1044,6 @@ static int mmc_sdio_resume(struct mmc_host *host)
static int mmc_sdio_power_restore(struct mmc_host *host)
{
int ret;
- u32 ocr, rocr;
BUG_ON(!host);
BUG_ON(!host->card);
@@ -1067,28 +1065,17 @@ static int mmc_sdio_power_restore(struct mmc_host *host)
* for OLPC SD8686 (which expects a [CMD5,5,3,7] init sequence), and
* harmless in other situations.
*
- * With these steps taken, mmc_select_voltage() is also required to
- * restore the correct voltage setting of the card.
*/
sdio_reset(host);
mmc_go_idle(host);
mmc_send_if_cond(host, host->ocr_avail);
- ret = mmc_send_io_op_cond(host, 0, &ocr);
+ ret = mmc_send_io_op_cond(host, 0, NULL);
if (ret)
goto out;
- if (host->ocr_avail_sdio)
- host->ocr_avail = host->ocr_avail_sdio;
-
- rocr = mmc_select_voltage(host, ocr & ~0x7F);
- if (!rocr) {
- ret = -EINVAL;
- goto out;
- }
-
- ret = mmc_sdio_init_card(host, rocr, host->card,
+ ret = mmc_sdio_init_card(host, host->card->ocr, host->card,
mmc_card_keep_power(host));
if (!ret && host->sdio_irqs)
mmc_signal_sdio_irq(host);
--
1.7.9.5
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