diff options
Diffstat (limited to 'drivers/mmc/core')
-rw-r--r-- | drivers/mmc/core/core.c | 29 | ||||
-rw-r--r-- | drivers/mmc/core/sdio_io.c | 99 |
2 files changed, 126 insertions, 2 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index ede5d1e2e20d..3ee5b8c3b5ce 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -3,7 +3,7 @@ * * Copyright (C) 2003-2004 Russell King, All Rights Reserved. * SD support Copyright (C) 2004 Ian Molton, All Rights Reserved. - * Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved. + * Copyright (C) 2005-2008 Pierre Ossman, All Rights Reserved. * MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved. * * This program is free software; you can redistribute it and/or modify @@ -295,6 +295,33 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card) EXPORT_SYMBOL(mmc_set_data_timeout); /** + * mmc_align_data_size - pads a transfer size to a more optimal value + * @card: the MMC card associated with the data transfer + * @sz: original transfer size + * + * Pads the original data size with a number of extra bytes in + * order to avoid controller bugs and/or performance hits + * (e.g. some controllers revert to PIO for certain sizes). + * + * Returns the improved size, which might be unmodified. + * + * Note that this function is only relevant when issuing a + * single scatter gather entry. + */ +unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz) +{ + /* + * FIXME: We don't have a system for the controller to tell + * the core about its problems yet, so for now we just 32-bit + * align the size. + */ + sz = ((sz + 3) / 4) * 4; + + return sz; +} +EXPORT_SYMBOL(mmc_align_data_size); + +/** * __mmc_claim_host - exclusively claim a host * @host: mmc host to claim * @abort: whether or not the operation should be aborted diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c index 625b92ce9cef..6ee7861fceae 100644 --- a/drivers/mmc/core/sdio_io.c +++ b/drivers/mmc/core/sdio_io.c @@ -1,7 +1,7 @@ /* * linux/drivers/mmc/core/sdio_io.c * - * Copyright 2007 Pierre Ossman + * Copyright 2007-2008 Pierre Ossman * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -189,6 +189,103 @@ int sdio_set_block_size(struct sdio_func *func, unsigned blksz) EXPORT_SYMBOL_GPL(sdio_set_block_size); +/** + * sdio_align_size - pads a transfer size to a more optimal value + * @func: SDIO function + * @sz: original transfer size + * + * Pads the original data size with a number of extra bytes in + * order to avoid controller bugs and/or performance hits + * (e.g. some controllers revert to PIO for certain sizes). + * + * If possible, it will also adjust the size so that it can be + * handled in just a single request. + * + * Returns the improved size, which might be unmodified. + */ +unsigned int sdio_align_size(struct sdio_func *func, unsigned int sz) +{ + unsigned int orig_sz; + unsigned int blk_sz, byte_sz; + unsigned chunk_sz; + + orig_sz = sz; + + /* + * Do a first check with the controller, in case it + * wants to increase the size up to a point where it + * might need more than one block. + */ + sz = mmc_align_data_size(func->card, sz); + + /* + * If we can still do this with just a byte transfer, then + * we're done. + */ + if ((sz <= func->cur_blksize) && (sz <= 512)) + return sz; + + if (func->card->cccr.multi_block) { + /* + * Check if the transfer is already block aligned + */ + if ((sz % func->cur_blksize) == 0) + return sz; + + /* + * Realign it so that it can be done with one request, + * and recheck if the controller still likes it. + */ + blk_sz = ((sz + func->cur_blksize - 1) / + func->cur_blksize) * func->cur_blksize; + blk_sz = mmc_align_data_size(func->card, blk_sz); + + /* + * This value is only good if it is still just + * one request. + */ + if ((blk_sz % func->cur_blksize) == 0) + return blk_sz; + + /* + * We failed to do one request, but at least try to + * pad the remainder properly. + */ + byte_sz = mmc_align_data_size(func->card, + sz % func->cur_blksize); + if ((byte_sz <= func->cur_blksize) && (byte_sz <= 512)) { + blk_sz = sz / func->cur_blksize; + return blk_sz * func->cur_blksize + byte_sz; + } + } else { + /* + * We need multiple requests, so first check that the + * controller can handle the chunk size; + */ + chunk_sz = mmc_align_data_size(func->card, + min(func->cur_blksize, 512u)); + if (chunk_sz == min(func->cur_blksize, 512u)) { + /* + * Fix up the size of the remainder (if any) + */ + byte_sz = orig_sz % chunk_sz; + if (byte_sz) { + byte_sz = mmc_align_data_size(func->card, + byte_sz); + } + + return (orig_sz / chunk_sz) * chunk_sz + byte_sz; + } + } + + /* + * The controller is simply incapable of transferring the size + * we want in decent manner, so just return the original size. + */ + return orig_sz; +} +EXPORT_SYMBOL_GPL(sdio_align_size); + /* Split an arbitrarily sized data transfer into several * IO_RW_EXTENDED commands. */ static int sdio_io_rw_ext_helper(struct sdio_func *func, int write, |