From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756617Ab1IGQZ0 (ORCPT ); Wed, 7 Sep 2011 12:25:26 -0400 Received: from newsmtp5.atmel.com ([204.2.163.5]:8999 "EHLO sjogate2.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754680Ab1IGQZY (ORCPT ); Wed, 7 Sep 2011 12:25:24 -0400 From: Nicolas Ferre To: cjb@laptop.org, linux-mmc@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Nicolas Ferre Subject: [RFC PATCH] mmc: sdio: rw extended, use a sg entry for each block Date: Wed, 7 Sep 2011 13:40:20 +0200 Message-Id: <1315395620-22641-1-git-send-email-nicolas.ferre@atmel.com> X-Mailer: git-send-email 1.7.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While using io multiple blocks operations, change the way that sg is built: use one sg entry for each block instead of aggregating the whole buffer in a single sg entry. Using a single sg entry for a multiple block command may lead to misunderstanding between the sd/mmc and the DMA controllers. In fact, the knowledge of the block length will allow both controllers to optimize burst sizes on internal bus while dealing with those data. Use a sg table to store start addresses of blocks within the data buffer. Signed-off-by: Nicolas Ferre --- drivers/mmc/core/sdio_ops.c | 38 +++++++++++++++++++++++++++++--------- 1 files changed, 29 insertions(+), 9 deletions(-) diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c index f087d87..aea6978 100644 --- a/drivers/mmc/core/sdio_ops.c +++ b/drivers/mmc/core/sdio_ops.c @@ -124,7 +124,7 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn, struct mmc_request mrq = {0}; struct mmc_command cmd = {0}; struct mmc_data data = {0}; - struct scatterlist sg; + struct sg_table sgt; BUG_ON(!card); BUG_ON(fn > 7); @@ -144,24 +144,44 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn, cmd.arg |= fn << 28; cmd.arg |= incr_addr ? 0x04000000 : 0x00000000; cmd.arg |= addr << 9; - if (blocks == 1 && blksz <= 512) - cmd.arg |= (blksz == 512) ? 0 : blksz; /* byte mode */ - else - cmd.arg |= 0x08000000 | blocks; /* block mode */ + if (blocks == 1 && blksz <= 512) { + /* byte mode */ + struct scatterlist sg; + + cmd.arg |= (blksz == 512) ? 0 : blksz; + sg_init_one(&sg, buf, blksz * blocks); + + data.sg = &sg; + data.sg_len = 1; + } else { + /* block mode */ + struct scatterlist *sg_ptr; + int i; + + cmd.arg |= 0x08000000 | blocks; + if (sg_alloc_table(&sgt, blocks, GFP_KERNEL)) + return -ENOMEM; + for_each_sg(sgt.sgl, sg_ptr, sgt.nents, i) { + sg_set_buf(sg_ptr, buf + i * blksz, blksz); + } + + data.sg = sgt.sgl; + data.sg_len = sgt.nents; + } + cmd.flags = MMC_RSP_SPI_R5 | MMC_RSP_R5 | MMC_CMD_ADTC; data.blksz = blksz; data.blocks = blocks; data.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ; - data.sg = &sg; - data.sg_len = 1; - - sg_init_one(&sg, buf, blksz * blocks); mmc_set_data_timeout(&data, card); mmc_wait_for_req(card->host, &mrq); + if (blocks != 1 || blksz > 512) + sg_free_table(&sgt); + if (cmd.error) return cmd.error; if (data.error) -- 1.7.3