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From:   Ulf Hansson <ulf.hansson@linaro.org>
To:     linux-mmc@vger.kernel.org,
        Jean Rene Dawin <jdawin@math.uni-bielefeld.de>,
        "H . Nikolaus Schaller" <hns@goldelico.com>
Cc:     Ulf Hansson <ulf.hansson@linaro.org>,
        Huijin Park <huijin.park@samsung.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] mmc: core: Restore (almost) the busy polling for MMC_SEND_OP_COND
Date:   Fri,  4 Mar 2022 11:56:56 +0100
Message-Id: <20220304105656.149281-1-ulf.hansson@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Commit 76bfc7ccc2fa ("mmc: core: adjust polling interval for CMD1"),
significantly decreased the polling period from ~10-12ms into just a couple
of us. The purpose was to decrease the total time spent in the busy polling
loop, but unfortunate it has lead to problems, that causes eMMC cards to
never gets out busy and thus fails to be initialized.

To fix the problem, but also to try to keep some of the new improved
behaviour, let's start by using a polling period of 1-2ms, which then
increases for each loop, according to common polling loop in
__mmc_poll_for_busy().

Reported-by: Jean Rene Dawin <jdawin@math.uni-bielefeld.de>
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Cc: Huijin Park <huijin.park@samsung.com>
Fixes: 76bfc7ccc2fa ("mmc: core: adjust polling interval for CMD1")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Jean Rene and H. Nikolaus, if this doesn't work, please try extending the
the MMC_OP_COND_PERIOD_US a bit, to so see if we can find a value that always
works.

Kind regards
Uffe

---
 drivers/mmc/core/block.c   |  2 +-
 drivers/mmc/core/mmc.c     |  2 +-
 drivers/mmc/core/mmc_ops.c | 13 +++++++++----
 drivers/mmc/core/mmc_ops.h |  3 ++-
 drivers/mmc/core/sd.c      |  2 +-
 5 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 8d718aa56d33..4e67c1403cc9 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1908,7 +1908,7 @@ static int mmc_blk_card_busy(struct mmc_card *card, struct request *req)
 
 	cb_data.card = card;
 	cb_data.status = 0;
-	err = __mmc_poll_for_busy(card->host, MMC_BLK_TIMEOUT_MS,
+	err = __mmc_poll_for_busy(card->host, 0, MMC_BLK_TIMEOUT_MS,
 				  &mmc_blk_busy_cb, &cb_data);
 
 	/*
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 13abfcd130a5..43d1b9b2fa49 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1962,7 +1962,7 @@ static int mmc_sleep(struct mmc_host *host)
 		goto out_release;
 	}
 
-	err = __mmc_poll_for_busy(host, timeout_ms, &mmc_sleep_busy_cb, host);
+	err = __mmc_poll_for_busy(host, 0, timeout_ms, &mmc_sleep_busy_cb, host);
 
 out_release:
 	mmc_retune_release(host);
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index d63d1c735335..180d7e9d3400 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -21,6 +21,8 @@
 
 #define MMC_BKOPS_TIMEOUT_MS		(120 * 1000) /* 120s */
 #define MMC_SANITIZE_TIMEOUT_MS		(240 * 1000) /* 240s */
+#define MMC_OP_COND_PERIOD_US		(1 * 1000) /* 1ms */
+#define MMC_OP_COND_TIMEOUT_MS		1000 /* 1s */
 
 static const u8 tuning_blk_pattern_4bit[] = {
 	0xff, 0x0f, 0xff, 0x00, 0xff, 0xcc, 0xc3, 0xcc,
@@ -232,7 +234,9 @@ int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
 	cmd.arg = mmc_host_is_spi(host) ? 0 : ocr;
 	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R3 | MMC_CMD_BCR;
 
-	err = __mmc_poll_for_busy(host, 1000, &__mmc_send_op_cond_cb, &cb_data);
+	err = __mmc_poll_for_busy(host, MMC_OP_COND_PERIOD_US,
+				  MMC_OP_COND_TIMEOUT_MS,
+				  &__mmc_send_op_cond_cb, &cb_data);
 	if (err)
 		return err;
 
@@ -495,13 +499,14 @@ static int mmc_busy_cb(void *cb_data, bool *busy)
 	return 0;
 }
 
-int __mmc_poll_for_busy(struct mmc_host *host, unsigned int timeout_ms,
+int __mmc_poll_for_busy(struct mmc_host *host, unsigned int period_us,
+			unsigned int timeout_ms,
 			int (*busy_cb)(void *cb_data, bool *busy),
 			void *cb_data)
 {
 	int err;
 	unsigned long timeout;
-	unsigned int udelay = 32, udelay_max = 32768;
+	unsigned int udelay = period_us ? period_us : 32, udelay_max = 32768;
 	bool expired = false;
 	bool busy = false;
 
@@ -546,7 +551,7 @@ int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
 	cb_data.retry_crc_err = retry_crc_err;
 	cb_data.busy_cmd = busy_cmd;
 
-	return __mmc_poll_for_busy(host, timeout_ms, &mmc_busy_cb, &cb_data);
+	return __mmc_poll_for_busy(host, 0, timeout_ms, &mmc_busy_cb, &cb_data);
 }
 EXPORT_SYMBOL_GPL(mmc_poll_for_busy);
 
diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
index 9c813b851d0b..09ffbc00908b 100644
--- a/drivers/mmc/core/mmc_ops.h
+++ b/drivers/mmc/core/mmc_ops.h
@@ -41,7 +41,8 @@ int mmc_can_ext_csd(struct mmc_card *card);
 int mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);
 bool mmc_prepare_busy_cmd(struct mmc_host *host, struct mmc_command *cmd,
 			  unsigned int timeout_ms);
-int __mmc_poll_for_busy(struct mmc_host *host, unsigned int timeout_ms,
+int __mmc_poll_for_busy(struct mmc_host *host, unsigned int period_us,
+			unsigned int timeout_ms,
 			int (*busy_cb)(void *cb_data, bool *busy),
 			void *cb_data);
 int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 24b0418a24bb..68df6b2f49cc 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1671,7 +1671,7 @@ static int sd_poweroff_notify(struct mmc_card *card)
 
 	cb_data.card = card;
 	cb_data.reg_buf = reg_buf;
-	err = __mmc_poll_for_busy(card->host, SD_POWEROFF_NOTIFY_TIMEOUT_MS,
+	err = __mmc_poll_for_busy(card->host, 0, SD_POWEROFF_NOTIFY_TIMEOUT_MS,
 				  &sd_busy_poweroff_notify_cb, &cb_data);
 
 out:
-- 
2.25.1