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	SDHCI changed from using a tasklet to finish requests, to using an IRQ thread i.e. commitc07a48c265("mmc: sdhci: Remove finish_tasklet"). Because this increased the latency to complete requests, a preparatory change was made to complete the request from the IRQ handler if possible i.e. commit19d2f695f4("mmc: sdhci: Call mmc_request_done() from IRQ handler if possible"). That alleviated the situation for MMC block devices because the MMC block driver makes use of mmc_pre_req() and mmc_post_req() so that successful requests are completed in the IRQ handler and any DMA unmapping is handled separately in mmc_post_req(). However SDIO was still affected, and an example has been reported with up to 20% degradation in performance. Looking at SDIO I/O helper functions, sdio_io_rw_ext_helper() appeared to be a possible candidate for making use of asynchronous requests within its I/O loops, but analysis revealed that these loops almost never iterate more than once, so the complexity of the change would not be warrented. Instead, mmc_pre_req() and mmc_post_req() are added before and after I/O submission (mmc_wait_for_req) in mmc_io_rw_extended(). This still has the potential benefit of reducing the duration of interrupt handlers, as well as addressing the latency issue for SDHCI. It also seems a more reasonable solution than forcing drivers to do everything in the IRQ handler. Reported-by: Dmitry Osipenko <digetx@gmail.com> Fixes:c07a48c265("mmc: sdhci: Remove finish_tasklet") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200903082007.18715-1-adrian.hunter@intel.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
		
			
				
	
	
		
			217 lines
		
	
	
	
		
			4.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			217 lines
		
	
	
	
		
			4.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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 *  linux/drivers/mmc/sdio_ops.c
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 *
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 *  Copyright 2006-2007 Pierre Ossman
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 */
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#include <linux/scatterlist.h>
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#include <linux/mmc/host.h>
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#include <linux/mmc/card.h>
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#include <linux/mmc/mmc.h>
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#include <linux/mmc/sdio.h>
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#include "core.h"
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#include "sdio_ops.h"
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int mmc_send_io_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
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{
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	struct mmc_command cmd = {};
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	int i, err = 0;
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	cmd.opcode = SD_IO_SEND_OP_COND;
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	cmd.arg = ocr;
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	cmd.flags = MMC_RSP_SPI_R4 | MMC_RSP_R4 | MMC_CMD_BCR;
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	for (i = 100; i; i--) {
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		err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
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		if (err)
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			break;
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		/* if we're just probing, do a single pass */
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		if (ocr == 0)
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			break;
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		/* otherwise wait until reset completes */
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		if (mmc_host_is_spi(host)) {
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			/*
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			 * Both R1_SPI_IDLE and MMC_CARD_BUSY indicate
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			 * an initialized card under SPI, but some cards
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			 * (Marvell's) only behave when looking at this
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			 * one.
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			 */
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			if (cmd.resp[1] & MMC_CARD_BUSY)
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				break;
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		} else {
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			if (cmd.resp[0] & MMC_CARD_BUSY)
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				break;
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		}
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		err = -ETIMEDOUT;
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		mmc_delay(10);
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	}
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	if (rocr)
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		*rocr = cmd.resp[mmc_host_is_spi(host) ? 1 : 0];
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	return err;
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}
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static int mmc_io_rw_direct_host(struct mmc_host *host, int write, unsigned fn,
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	unsigned addr, u8 in, u8 *out)
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{
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	struct mmc_command cmd = {};
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	int err;
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	if (fn > 7)
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		return -EINVAL;
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	/* sanity check */
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	if (addr & ~0x1FFFF)
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		return -EINVAL;
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	cmd.opcode = SD_IO_RW_DIRECT;
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	cmd.arg = write ? 0x80000000 : 0x00000000;
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	cmd.arg |= fn << 28;
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	cmd.arg |= (write && out) ? 0x08000000 : 0x00000000;
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	cmd.arg |= addr << 9;
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	cmd.arg |= in;
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	cmd.flags = MMC_RSP_SPI_R5 | MMC_RSP_R5 | MMC_CMD_AC;
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	err = mmc_wait_for_cmd(host, &cmd, 0);
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	if (err)
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		return err;
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	if (mmc_host_is_spi(host)) {
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		/* host driver already reported errors */
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	} else {
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		if (cmd.resp[0] & R5_ERROR)
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			return -EIO;
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		if (cmd.resp[0] & R5_FUNCTION_NUMBER)
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			return -EINVAL;
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		if (cmd.resp[0] & R5_OUT_OF_RANGE)
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			return -ERANGE;
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	}
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	if (out) {
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		if (mmc_host_is_spi(host))
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			*out = (cmd.resp[0] >> 8) & 0xFF;
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		else
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			*out = cmd.resp[0] & 0xFF;
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	}
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	return 0;
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}
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int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn,
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	unsigned addr, u8 in, u8 *out)
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{
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	return mmc_io_rw_direct_host(card->host, write, fn, addr, in, out);
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}
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int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
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	unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz)
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{
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	struct mmc_request mrq = {};
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	struct mmc_command cmd = {};
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	struct mmc_data data = {};
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	struct scatterlist sg, *sg_ptr;
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	struct sg_table sgtable;
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	unsigned int nents, left_size, i;
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	unsigned int seg_size = card->host->max_seg_size;
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	int err;
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	WARN_ON(blksz == 0);
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	/* sanity check */
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	if (addr & ~0x1FFFF)
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		return -EINVAL;
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	mrq.cmd = &cmd;
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	mrq.data = &data;
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	cmd.opcode = SD_IO_RW_EXTENDED;
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	cmd.arg = write ? 0x80000000 : 0x00000000;
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	cmd.arg |= fn << 28;
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	cmd.arg |= incr_addr ? 0x04000000 : 0x00000000;
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	cmd.arg |= addr << 9;
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	if (blocks == 0)
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		cmd.arg |= (blksz == 512) ? 0 : blksz;	/* byte mode */
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	else
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		cmd.arg |= 0x08000000 | blocks;		/* block mode */
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	cmd.flags = MMC_RSP_SPI_R5 | MMC_RSP_R5 | MMC_CMD_ADTC;
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	data.blksz = blksz;
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	/* Code in host drivers/fwk assumes that "blocks" always is >=1 */
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	data.blocks = blocks ? blocks : 1;
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	data.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ;
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	left_size = data.blksz * data.blocks;
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	nents = DIV_ROUND_UP(left_size, seg_size);
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	if (nents > 1) {
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		if (sg_alloc_table(&sgtable, nents, GFP_KERNEL))
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			return -ENOMEM;
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		data.sg = sgtable.sgl;
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		data.sg_len = nents;
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		for_each_sg(data.sg, sg_ptr, data.sg_len, i) {
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			sg_set_buf(sg_ptr, buf + i * seg_size,
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				   min(seg_size, left_size));
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			left_size -= seg_size;
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		}
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	} else {
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		data.sg = &sg;
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		data.sg_len = 1;
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		sg_init_one(&sg, buf, left_size);
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	}
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	mmc_set_data_timeout(&data, card);
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	mmc_pre_req(card->host, &mrq);
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	mmc_wait_for_req(card->host, &mrq);
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	if (cmd.error)
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		err = cmd.error;
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	else if (data.error)
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		err = data.error;
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	else if (mmc_host_is_spi(card->host))
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		/* host driver already reported errors */
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		err = 0;
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	else if (cmd.resp[0] & R5_ERROR)
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		err = -EIO;
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	else if (cmd.resp[0] & R5_FUNCTION_NUMBER)
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		err = -EINVAL;
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	else if (cmd.resp[0] & R5_OUT_OF_RANGE)
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		err = -ERANGE;
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	else
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		err = 0;
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	mmc_post_req(card->host, &mrq, err);
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	if (nents > 1)
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		sg_free_table(&sgtable);
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	return err;
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}
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int sdio_reset(struct mmc_host *host)
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{
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	int ret;
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	u8 abort;
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	/* SDIO Simplified Specification V2.0, 4.4 Reset for SDIO */
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	ret = mmc_io_rw_direct_host(host, 0, 0, SDIO_CCCR_ABORT, 0, &abort);
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	if (ret)
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		abort = 0x08;
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	else
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		abort |= 0x08;
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	return mmc_io_rw_direct_host(host, 1, 0, SDIO_CCCR_ABORT, abort, NULL);
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}
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