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

[Marek Vasut <marex@denx.de>]

On Thursday, December 24, 2015 at 04:08:33 AM, Thomas Chou wrote:
> Hi Marek,
> 
> On 2015?12?24? 11:01, Marek Vasut wrote:
> > On Thursday, December 24, 2015 at 03:23:05 AM, Thomas Chou wrote:
> >> 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 *.
> > 
> > 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;

Please ignore what I said, sorry.