From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-bl2lp0205.outbound.protection.outlook.com ([207.46.163.205] helo=na01-bl2-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XFEhY-0008RL-Ue for linux-mtd@lists.infradead.org; Thu, 07 Aug 2014 03:49:17 +0000 From: Aaron Wu To: , , , , Subject: [PATCH] [mtd] gpio_flash: fix the bug in handling gpio flash read/write when offset + len from mtd exceeds the window size Date: Thu, 7 Aug 2014 11:43:49 +0800 Message-ID: <1407383029-24290-1-git-send-email-Aaron.wu@analog.com> MIME-Version: 1.0 Content-Type: text/plain Cc: Aaron Wu List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Signed-off-by: Aaron Wu fix the bug in handling gpio flash read/write when offset + len from mtd exceeds the window size --- drivers/mtd/maps/gpio-addr-flash.c | 43 ++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 14 deletions(-) diff --git a/drivers/mtd/maps/gpio-addr-flash.c b/drivers/mtd/maps/gpio-addr-flash.c index a4c477b..947631a 100644 --- a/drivers/mtd/maps/gpio-addr-flash.c +++ b/drivers/mtd/maps/gpio-addr-flash.c @@ -99,22 +99,29 @@ static map_word gf_read(struct map_info *map, unsigned long ofs) * @from: flash offset to copy from * @len: how much to copy * - * We rely on the MTD layer to chunk up copies such that a single request here - * will not cross a window size. This allows us to only wiggle the GPIOs once - * before falling back to a normal memcpy. Reading the higher layer code shows - * that this is indeed the case, but add a BUG_ON() to future proof. + *Toggle the correct GPIO according to @from to enable the right flash bank, + *still the read offset plus len may execceds the actual Window size,when + *this happnes, reverts the value for multiple read until all data is read. */ static void gf_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len) { struct async_state *state = gf_map_info_to_state(map); - gf_set_gpios(state, from); + int this_len; - /* BUG if operation crosses the win_size */ - BUG_ON(!((from + len) % state->win_size <= (from + len))); + while (len) { + if ((from % state->win_size) + len > state->win_size) + this_len = state->win_size - (from % state->win_size); + else + this_len = len; - /* operation does not cross the win_size, so one shot it */ - memcpy_fromio(to, map->virt + (from % state->win_size), len); + gf_set_gpios(state, from); + memcpy_fromio(to, map->virt + (from % state->win_size), + this_len); + len -= this_len; + from += this_len; + to += this_len; + } } /** @@ -147,13 +154,21 @@ static void gf_copy_to(struct map_info *map, unsigned long to, { struct async_state *state = gf_map_info_to_state(map); - gf_set_gpios(state, to); + int this_len; + + while (len) { + if ((to % state->win_size) + len > state->win_size) + this_len = state->win_size - (to % state->win_size); + else + this_len = len; - /* BUG if operation crosses the win_size */ - BUG_ON(!((to + len) % state->win_size <= (to + len))); + gf_set_gpios(state, to); + memcpy_toio(map->virt + (to % state->win_size), from, len); - /* operation does not cross the win_size, so one shot it */ - memcpy_toio(map->virt + (to % state->win_size), from, len); + len -= this_len; + to += this_len; + from += this_len; + } } static const char * const part_probe_types[] = { -- 1.7.9.5