linux-kernel - [PATCH v1 4/4]use HPI to interrupt background operations

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Date:	Tue, 23 Nov 2010 16:45:10 +0800
From:	Chuanxiao Dong <chuanxiao.dong@...el.com>
To:	linux-mmc@...r.kernel.org, cjb@...top.org
Cc:	linux-kernel@...r.kernel.org, alan@...ux.intel.com,
	arjan@...ux.intel.com, hang.yuan@...el.com
Subject: [PATCH v1 4/4]use HPI to interrupt background operations

>From 8d2cf8e4b890a3ef0c7b63da57b8b184ab64725d Mon Sep 17 00:00:00 2001
From: Chuanxiao Dong <chuanxiao.dong@...el.com>
Date: Tue, 23 Nov 2010 12:01:58 +0800
Subject: [PATCH 4/4] mmc: Add HPI operation to interrupt BKOPS

Before start a new user request, driver need to wait until the
BKOPS finished, or use HPI to interrupt the BKOPS since user request
has a higher priority than BKOPS.

This patch implemented using HPI to interrupt BKOPS if eMMC card
supports HPI.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@...el.com>
---
 drivers/mmc/core/core.c |   51 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 50 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6891169..644ce9d 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -202,6 +202,50 @@ static void mmc_wait_done(struct mmc_request *mrq)
 }
 
 /**
+ *	mmc_issue_hpi_cmd - start a hpi to interrupt background
+ *	operations
+ *	@card: MMC card need to interrupt
+ *
+ *  start MMC_SEND_STATUS/MMC_STOP_TRANSMISSION to stop the
+ *  background operations.
+ *
+ *  return value:
+ *  0: successfully interrupt BKOPS
+ *  -EINVAL: HPI command invalid
+ *  -EIO: failed when interrupt BKOPS
+ */
+static int mmc_issue_hpi_cmd(struct mmc_card *card)
+{
+	struct mmc_command cmd;
+	unsigned int opcode;
+	unsigned int flags;
+	int err;
+
+	opcode = card->ext_csd.hpi_cmd;
+	if (opcode == MMC_STOP_TRANSMISSION)
+		flags = MMC_RSP_R1B | MMC_CMD_AC;
+	else if (opcode == MMC_SEND_STATUS)
+		flags = MMC_RSP_R1 | MMC_CMD_AC;
+	else
+		return -EINVAL;
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	cmd.opcode = opcode;
+	cmd.arg = card->rca << 16 | 1;
+	err = mmc_wait_for_cmd(card->host, &cmd, 0);
+	if (err || (cmd.resp[0] & 0xFDF92000)) {
+		printk(KERN_ERR "error %d requesting status %#x\n",
+			err, cmd.resp[0]);
+		/*
+		 * abandon this BKOPS, let block layer handle
+		 * this
+		 */
+		return -EIO;
+	}
+	return 0;
+}
+
+/**
  *	mmc_wait_for_bkops- start a bkops check and wait for
  *	completion
  *	@card: MMC card need to check
@@ -224,9 +268,14 @@ retry:
 
 	if (card->ext_csd.hpi_en) {
 		/*
-		 * TODO
 		 * HPI to interrupt BKOPS if supported
 		 */
+		err = mmc_issue_hpi_cmd(card);
+		if (err == -EINVAL) {
+			/* disable HPI feature */
+			card->ext_csd.hpi_en = 0;
+			goto retry;
+		}
 	} else {
 		memset(&cmd, 0, sizeof(struct mmc_command));
 
-- 
1.6.6.1

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