linux-kernel - 答复: [PATCH] mmc: sdio: Fix sdio wait busy implement limitation

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Date:   Mon, 17 Apr 2017 08:36:00 +0000
From:   Jiajie Hao (郝加节) 
        <jiajie.hao@...iatek.com>
To:     Jiajie Hao (郝加节) 
        <jiajie.hao@...iatek.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>
CC:     "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        Chaotian Jing (井朝天) 
        <Chaotian.Jing@...iatek.com>,
        Yong Mao (毛勇) <yong.mao@...iatek.com>,
        Eddie Huang (黃智傑) 
        <eddie.huang@...iatek.com>,
        srv_heupstream <srv_heupstream@...iatek.com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: 答复: [PATCH] mmc: sdio: Fix sdio wait busy implement limitation

CC: linux-arm-kernel


Many thanks
Jiajie.

-----邮件原件-----
发件人: jiajie.hao@...iatek.com [mailto:jiajie.hao@...iatek.com] 
发送时间: 2017年4月17日 16:10
收件人: ulf.hansson@...aro.org
抄送: linus.walleij@...aro.org; Chaotian Jing (井朝天) <Chaotian.Jing@...iatek.com>; Yong Mao (毛勇) <yong.mao@...iatek.com>; Eddie Huang (黃智傑) <eddie.huang@...iatek.com>; srv_heupstream <srv_heupstream@...iatek.com>; linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org; linux-mediatek@...ts.infradead.org; linux-arm-kernel@...iatek.com; Jiajie Hao (郝加节) <jiajie.hao@...iatek.com>
主题: [PATCH] mmc: sdio: Fix sdio wait busy implement limitation

From: Jiajie Hao <jiajie.hao@...iatek.com>

The host may issue an I/O abort by writing to the CCCR at any time during I/O read operation via CMD52. And host may need suspend transcation during write busy stage in SDIO suspend/resume scenario.
From other side, a card may accept CMD52 during data transfer phase.

Previous implement would block issuing above command in busy stage.
It cause function driver can't implement as proper way and has no opportunity to do some coverage in error case via I/O abort etc.

We need bypass some necessary operation during busy check stage.

Change-Id: Ib5a4599a2a98cbcf441b564f5f6fbb10c8a59e1b
Signed-off-by: Jiajie Hao <jiajie.hao@...iatek.com>
---
 drivers/mmc/core/core.c     |    4 +++-
 drivers/mmc/core/sdio_ops.h |   10 ++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 926e0fd..9c9a4bc 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -234,8 +234,10 @@ static void __mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
 	/*
 	 * For sdio rw commands we must wait for card busy otherwise some
 	 * sdio devices won't work properly.
+	 * And bypass I/O abort, reset and bus suspend operations.
 	 */
-	if (mmc_is_io_op(mrq->cmd->opcode) && host->ops->card_busy) {
+	if (mmc_is_io_op(mrq->cmd->opcode) && host->ops->card_busy &&
+	    !mmc_is_io_bypass(mrq->cmd->opcode, mrq->cmd->arg)) {
 		int tries = 500; /* Wait aprox 500ms at maximum */
 
 		while (host->ops->card_busy(host) && --tries) diff --git a/drivers/mmc/core/sdio_ops.h b/drivers/mmc/core/sdio_ops.h index bed8a83..9896696 100644
--- a/drivers/mmc/core/sdio_ops.h
+++ b/drivers/mmc/core/sdio_ops.h
@@ -31,5 +31,15 @@ static inline bool mmc_is_io_op(u32 opcode)
 	return opcode == SD_IO_RW_DIRECT || opcode == SD_IO_RW_EXTENDED;  }
 
+static inline bool mmc_is_io_bypass(u32 opcode, u32 arg) {
+	u32 addr;
+
+	addr = (arg >> 9) & 0x1FFFF;
+
+	return ((opcode == SD_IO_RW_DIRECT) &&
+		(addr == SDIO_CCCR_ABORT || addr == SDIO_CCCR_SUSPEND)); }
+
 #endif
 
--
1.7.9.5