mmc: core: Fixup support for HW busy detection for HPI commands

In case the host specify a max_busy_timeout, we need to validate that the
needed timeout for the HPI command conforms to that requirement. If that's
not the case, let's convert from a R1B response to a R1 response, as to
instruct the host to avoid HW busy detection.

Additionally, when R1B is used we must also inform the host about the busy
timeout for the command, so let's do that via updating cmd.busy_timeout.

Finally, when R1B is used and in case the host supports HW busy detection,
there should be no need for doing polling, so then skip that.
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/20200204085449.32585-12-ulf.hansson@linaro.org

drivers/mmc/core/mmc_ops.c

@@ -834,27 +834,41 @@ int mmc_bus_test(struct mmc_card *card, u8 bus_width)
 static int mmc_send_hpi_cmd(struct mmc_card *card)
 {
 	unsigned int busy_timeout_ms = card->ext_csd.out_of_int_time;
+	struct mmc_host *host = card->host;
+	bool use_r1b_resp = true;
 	struct mmc_command cmd = {};
-	unsigned int opcode;
 	int err;
 
-	opcode = card->ext_csd.hpi_cmd;
-	if (opcode == MMC_STOP_TRANSMISSION)
+	cmd.opcode = card->ext_csd.hpi_cmd;
+	cmd.arg = card->rca << 16 | 1;
+
+	/*
+	 * Make sure the host's max_busy_timeout fit the needed timeout for HPI.
+	 * In case it doesn't, let's instruct the host to avoid HW busy
+	 * detection, by using a R1 response instead of R1B.
+	 */
+	if (host->max_busy_timeout && busy_timeout_ms > host->max_busy_timeout)
+		use_r1b_resp = false;
+
+	if (cmd.opcode == MMC_STOP_TRANSMISSION && use_r1b_resp) {
 		cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
-	else if (opcode == MMC_SEND_STATUS)
+		cmd.busy_timeout = busy_timeout_ms;
+	} else {
 		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+		use_r1b_resp = false;
+	}
 
-	cmd.opcode = opcode;
-	cmd.arg = card->rca << 16 | 1;
-
-	err = mmc_wait_for_cmd(card->host, &cmd, 0);
+	err = mmc_wait_for_cmd(host, &cmd, 0);
 	if (err) {
-		pr_warn("%s: error %d interrupting operation. "
-			"HPI command response %#x\n", mmc_hostname(card->host),
-			err, cmd.resp[0]);
+		pr_warn("%s: HPI error %d. Command response %#x\n",
+			mmc_hostname(host), err, cmd.resp[0]);
 		return err;
 	}
 
+	/* No need to poll when using HW busy detection. */
+	if (host->caps & MMC_CAP_WAIT_WHILE_BUSY && use_r1b_resp)
+		return 0;
+
 	/* Let's poll to find out when the HPI request completes. */
 	return mmc_poll_for_busy(card, busy_timeout_ms, MMC_BUSY_HPI);
 }