From: Marek Behún marek.behun@nic.cz
The _erase() method of the mtdpart driver, part_erase(), currently implements offset shifting (for given mtdpart partition) in a weird way: 1. part_erase() adds partition offset to block address 2. parent driver's _erase() method is called 3. parent driver's _erase() method calls mtd_erase_callback() 4. mtd_erase_callback() subtracts partition offset from block address so that the callback function is given correct address The problem here is that if the parent's driver does not call mtd_erase_callback() in some scenario (this was recently a case for spi_nor_erase(), which did not call mtd_erase_callback() at all), the offset is not shifted back.
Moreover the code would be more readable if part_erase() not only added partition offset before calling parent's _erase(), but also subtracted it back afterwards. Currently the mtd_erase_callback() is expected to do this subtracting since it does have to do it anyway.
Add the more steps to this procedure: 5. mtd_erase_callback() adds partition offset to block address so that it returns the the erase_info structure members as it received them 6. part_erase() subtracts partition offset from block address
This makes the code more logical and also prevents errors in case parent's driver does not call mtd_erase_callback() for some reason.
(BTW, the purpose of mtd_erase_callback() in Linux is to inform the caller that it is done, since in Linux erasing is done asynchronously. We are abusing the purpose of mtd_erase_callback() in U-Boot for completely different purpose. The callback function itself has empty implementation in all cases in U-Boot.)
Signed-off-by: Marek Behún marek.behun@nic.cz Reviewed-by: Simon Glass sjg@chromium.org Tested-by: Masami Hiramatsu masami.hiramatsu@linaro.org --- drivers/mtd/mtdpart.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index aa58f722da..6ab481a7b1 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -446,24 +446,34 @@ static int part_erase(struct mtd_info *mtd, struct erase_info *instr) int ret;
instr->addr += mtd->offset; + ret = mtd->parent->_erase(mtd->parent, instr); - if (ret) { - if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) - instr->fail_addr -= mtd->offset; - instr->addr -= mtd->offset; - } + if (ret && instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) + instr->fail_addr -= mtd->offset; + + instr->addr -= mtd->offset; + return ret; }
void mtd_erase_callback(struct erase_info *instr) { - if (instr->mtd->_erase == part_erase) { + if (!instr->callback) + return; + + if (instr->mtd->_erase == part_erase && instr->len) { if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) instr->fail_addr -= instr->mtd->offset; instr->addr -= instr->mtd->offset; } - if (instr->callback) - instr->callback(instr); + + instr->callback(instr); + + if (instr->mtd->_erase == part_erase && instr->len) { + if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN) + instr->fail_addr += instr->mtd->offset; + instr->addr += instr->mtd->offset; + } } EXPORT_SYMBOL_GPL(mtd_erase_callback);