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

[Thomas Chou <thomas@wytron.com.tw>]

Hi Marek,

On 2015?12?24? 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@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 *.

Best regards,
Thomas