[U-Boot] [PATCH 3/5] altera_qspi: skip erase if the sector is blank

[Thomas Chou]

Hi Marek,

On 2015年12月24日 11:01, Marek Vasut wrote:
> On Thursday, December 24, 2015 at 03:23:05 AM, Thomas Chou wrote:
>> Hi Marek,
>>
>> On 2015年12月24日 09:28, Marek Vasut wrote:
>>> On Thursday, December 24, 2015 at 01:51:22 AM, Thomas Chou wrote:
>>>> Skip erase if the sector is blank. The sector erase is slow, and
>>>> may take 0.7 sec typically or up to 3 sec worst-case.
>>>>
>>>> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
>>>> ---
>>>>
>>>>    drivers/mtd/altera_qspi.c | 39 +++++++++++++++++++++++++--------------
>>>>    1 file changed, 25 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/mtd/altera_qspi.c b/drivers/mtd/altera_qspi.c
>>>> index b0d4f2c..8a630a6 100644
>>>> --- a/drivers/mtd/altera_qspi.c
>>>> +++ b/drivers/mtd/altera_qspi.c
>>>> @@ -131,24 +131,35 @@ static int altera_qspi_erase(struct mtd_info *mtd,
>>>> struct erase_info *instr) size_t end = addr + len;
>>>>
>>>>    	u32 sect;
>>>>    	u32 stat;
>>>>
>>>> +	u32 *flash, *last;
>>>>
>>>>    	instr->state = MTD_ERASING;
>>>>    	addr &= ~(mtd->erasesize - 1); /* get lower aligned address */
>>>>    	while (addr < end) {
>>>>
>>>> -		sect = addr / mtd->erasesize;
>>>> -		sect <<= 8;
>>>> -		sect |= QUADSPI_MEM_OP_SECTOR_ERASE;
>>>> -		debug("erase %08x\n", sect);
>>>> -		writel(sect, &regs->mem_op);
>>>> -		stat = readl(&regs->isr);
>>>> -		if (stat & QUADSPI_ISR_ILLEGAL_ERASE) {
>>>> -			/* erase failed, sector might be protected */
>>>> -			debug("erase %08x fail %x\n", sect, stat);
>>>> -			writel(stat, &regs->isr); /* clear isr */
>>>> -			instr->fail_addr = addr;
>>>> -			instr->state = MTD_ERASE_FAILED;
>>>> -			mtd_erase_callback(instr);
>>>> -			return -EIO;
>>>> +		flash = pdata->base + addr;
>>>> +		last = pdata->base + addr + mtd->erasesize;
>>>> +		/* skip erase if sector is blank */
>>>> +		while (flash < last) {
>>>> +			if (readl(flash) != 0xffffffff)
>>>> +				break;
>>>> +			flash++;
>>>
>>> Shouldn't $last be divided by 4 ? $flash is u32 * afterall .
>>
>> No. Both flash and last are assigned with byte addressing from
>> pdata->base, which is void *.
>
> The data type of both $flash and $last is u32 * though?

Yes.

flash = pdata->base + addr;

will be the same as,

flash = pdata->base;
flash += addr / 4;

Best regards,
Thomas