Previously the dw_mmc driver would ignore any requests to disable the
card's clock. This doesn't seem like a good thing in general, but had
one extra bad side effect in the following situtation:
* mmc core would set clk to 400kHz at boot time while initting
* mmc core would set clk to 0 since no card, but it would be ignored.
* suspend to ram and resume; clocks in the dw_mmc IP block are now 0
but dw_mmc thinks that they're 400kHz (it ignored the set to 0).
* insert card
* mmc core would set clk to 400kHz which would be considered a no-op.
Note that if there is no card in the slot and we do a suspend/resume
cycle, we _do_ still end up with differences in a dw_mmc register
dump, but the differences are clock related and we've got the clock
disabled both before and after, so this should be OK.
Signed-off-by: Doug Anderson <diand...@chromium.org>
---
Changes in v6:
- Replaces previous pathes that ensured saving/restoring clocks.
drivers/mmc/host/dw_mmc.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index ee5f167..f6c7545 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -635,7 +635,11 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot,
bool force_clkinit)
u32 div;
u32 clk_en_a;
- if (slot->clock != host->current_speed || force_clkinit) {
+ if (slot->clock == 0) {
+ mci_writel(host, CLKENA, 0);
+ mci_send_cmd(slot,
+ SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
+ } else if (slot->clock != host->current_speed || force_clkinit) {
div = host->bus_hz / slot->clock;
if (host->bus_hz % slot->clock && host->bus_hz > slot->clock)
/*
@@ -675,9 +679,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool
force_clkinit)
/* inform CIU */
mci_send_cmd(slot,
SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
-
- host->current_speed = slot->clock;
}
+ host->current_speed = slot->clock;
/* Set the current slot bus width */
mci_writel(host, CTYPE, (slot->ctype << slot->id));
@@ -807,13 +810,11 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct
mmc_ios *ios)
mci_writel(slot->host, UHS_REG, regs);
- if (ios->clock) {
- /*
- * Use mirror of ios->clock to prevent race with mmc
- * core ios update when finding the minimum.
- */
- slot->clock = ios->clock;
- }
+ /*
+ * Use mirror of ios->clock to prevent race with mmc
+ * core ios update when finding the minimum.
+ */
+ slot->clock = ios->clock;
if (drv_data && drv_data->set_ios)
drv_data->set_ios(slot->host, ios);
--
1.8.3
--
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