mmc: core: run clock scaling only in valid card state

Clock scaling requires the tuning and if the tuning command
is sent to the card in invalid state, tuning procedure will
fail.

With urgent request mechanism implemented, there is a chance
that clock scaling invoked when card is not in a proper state
to receive the tuning command.

This change checks the card state (by sending the status command)
before invoking the clock scaling request.

Change-Id: Icb71a8e74a9afdc70380a5901cd3d28931959e9c
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 843edbed3ac9..2e94974d4d14 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2767,6 +2767,30 @@ out:
 	return;
 }
 
+static bool mmc_is_vaild_state_for_clk_scaling(struct mmc_host *host)
+{
+	struct mmc_card *card = host->card;
+	u32 status;
+	bool ret = false;
+
+	if (!card)
+		goto out;
+
+	if (mmc_send_status(card, &status)) {
+		pr_err("%s: Get card status fail\n", mmc_hostname(card->host));
+		goto out;
+	}
+
+	switch (R1_CURRENT_STATE(status)) {
+	case R1_STATE_TRAN:
+		ret = true;
+		break;
+	default:
+		break;
+	}
+out:
+	return ret;
+}
 
 /**
  * mmc_clk_scaling() - clock scaling decision algorithm
@@ -2839,6 +2863,10 @@ static void mmc_clk_scaling(struct mmc_host *host, bool from_wq)
 			if (!from_wq)
 				cancel_delayed_work_sync(
 						&host->clk_scaling.work);
+
+			if (!mmc_is_vaild_state_for_clk_scaling(host))
+				goto bypass_scaling;
+
 			err = host->bus_ops->change_bus_speed(host, &freq);
 			if (!err)
 				host->clk_scaling.curr_freq = freq;
@@ -2860,6 +2888,7 @@ static void mmc_clk_scaling(struct mmc_host *host, bool from_wq)
 	}
 
 	mmc_reset_clk_scale_stats(host);
+bypass_scaling:
 	host->clk_scaling.in_progress = false;
 out:
 	return;