mmc: core: Convert to mmc_poll_for_busy() for erase/trim/discard

Rather than open coding the polling loop in mmc_do_erase(), let's convert
to use mmc_poll_for_busy().

To allow a slightly different error parsing during polling, compared to the
__mmc_switch() case, a new in-parameter to mmc_poll_for_busy() is needed,
but other than that the conversion is straight forward.

Besides addressing the open coding issue, moving to mmc_poll_for_busy() for
erase/trim/discard improves the behaviour according to below.

- Adds support for polling via the optional ->card_busy() host ops.
- Returns zero to indicate success when the final polling attempt finds the
  card non-busy, even if the timeout expired.
- Exits the polling loop when state moves to R1_STATE_TRAN, rather than
  when leaving R1_STATE_PRG.
- Decreases the starting range for throttling to 32-64us.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Tested-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200204085449.32585-9-ulf.hansson@linaro.org

drivers/mmc/core/core.c

@@ -1658,8 +1658,6 @@ static int mmc_do_erase(struct mmc_card *card, unsigned int from,
 	struct mmc_command cmd = {};
 	unsigned int qty = 0, busy_timeout = 0;
 	bool use_r1b_resp = false;
-	unsigned long timeout;
-	int loop_udelay=64, udelay_max=32768;
 	int err;
 
 	mmc_retune_hold(card->host);
@@ -1763,38 +1761,8 @@ static int mmc_do_erase(struct mmc_card *card, unsigned int from,
 	if ((card->host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
 		goto out;
 
-	timeout = jiffies + msecs_to_jiffies(busy_timeout);
-	do {
-		memset(&cmd, 0, sizeof(struct mmc_command));
-		cmd.opcode = MMC_SEND_STATUS;
-		cmd.arg = card->rca << 16;
-		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
-		/* Do not retry else we can't see errors */
-		err = mmc_wait_for_cmd(card->host, &cmd, 0);
-		if (err || R1_STATUS(cmd.resp[0])) {
-			pr_err("error %d requesting status %#x\n",
-				err, cmd.resp[0]);
-			err = -EIO;
-			goto out;
-		}
-
-		/* Timeout if the device never becomes ready for data and
-		 * never leaves the program state.
-		 */
-		if (time_after(jiffies, timeout)) {
-			pr_err("%s: Card stuck in programming state! %s\n",
-				mmc_hostname(card->host), __func__);
-			err =  -EIO;
-			goto out;
-		}
-		if ((cmd.resp[0] & R1_READY_FOR_DATA) &&
-		    R1_CURRENT_STATE(cmd.resp[0]) != R1_STATE_PRG)
-			break;
-
-		usleep_range(loop_udelay, loop_udelay*2);
-		if (loop_udelay < udelay_max)
-			loop_udelay *= 2;
-	} while (1);
+	/* Let's poll to find out when the erase operation completes. */
+	err = mmc_poll_for_busy(card, busy_timeout, MMC_BUSY_ERASE);
 
 out:
 	mmc_retune_release(card->host);

drivers/mmc/core/mmc_ops.c

@@ -445,7 +445,7 @@ int mmc_switch_status(struct mmc_card *card, bool crc_err_fatal)
 }
 
 static int mmc_busy_status(struct mmc_card *card, bool retry_crc_err,
-			   bool *busy)
+			   enum mmc_busy_cmd busy_cmd, bool *busy)
 {
 	struct mmc_host *host = card->host;
 	u32 status = 0;
@@ -464,16 +464,27 @@ static int mmc_busy_status(struct mmc_card *card, bool retry_crc_err,
 	if (err)
 		return err;
 
-	err = mmc_switch_status_error(card->host, status);
+	switch (busy_cmd) {
+	case MMC_BUSY_CMD6:
+		err = mmc_switch_status_error(card->host, status);
+		break;
+	case MMC_BUSY_ERASE:
+		err = R1_STATUS(status) ? -EIO : 0;
+		break;
+	default:
+		err = -EINVAL;
+	}
+
 	if (err)
 		return err;
 
 	*busy = !mmc_ready_for_data(status);
 	return 0;
 }
 
-static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
-			bool send_status, bool retry_crc_err)
+static int __mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
+			       bool send_status, bool retry_crc_err,
+			       enum mmc_busy_cmd busy_cmd)
 {
 	struct mmc_host *host = card->host;
 	int err;
@@ -500,7 +511,7 @@ static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
 		 */
 		expired = time_after(jiffies, timeout);
 
-		err = mmc_busy_status(card, retry_crc_err, &busy);
+		err = mmc_busy_status(card, retry_crc_err, busy_cmd, &busy);
 		if (err)
 			return err;
 
@@ -522,6 +533,12 @@ static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
 	return 0;
 }
 
+int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
+		      enum mmc_busy_cmd busy_cmd)
+{
+	return __mmc_poll_for_busy(card, timeout_ms, true, false, busy_cmd);
+}
+
 /**
  *	__mmc_switch - modify EXT_CSD register
  *	@card: the MMC card associated with the data transfer
@@ -591,7 +608,8 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 		goto out_tim;
 
 	/* Let's try to poll to find out when the command is completed. */
-	err = mmc_poll_for_busy(card, timeout_ms, send_status, retry_crc_err);
+	err = __mmc_poll_for_busy(card, timeout_ms, send_status, retry_crc_err,
+				  MMC_BUSY_CMD6);
 	if (err)
 		goto out;
 

drivers/mmc/core/mmc_ops.h

@@ -10,6 +10,11 @@
 
 #include <linux/types.h>
 
+enum mmc_busy_cmd {
+	MMC_BUSY_CMD6,
+	MMC_BUSY_ERASE,
+};
+
 struct mmc_host;
 struct mmc_card;
 
@@ -30,6 +35,8 @@ int mmc_interrupt_hpi(struct mmc_card *card);
 int mmc_can_ext_csd(struct mmc_card *card);
 int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
 int mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);
+int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
+		      enum mmc_busy_cmd busy_cmd);
 int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 		unsigned int timeout_ms, unsigned char timing,
 		bool send_status, bool retry_crc_err);