diff options
Diffstat (limited to 'drivers/mmc/core/core.c')
| -rw-r--r-- | drivers/mmc/core/core.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index ede5d1e2e20..3ee5b8c3b5c 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 |