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

[Marek Vasut]

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 .

> +		}
> +		if (flash < last) {
> +			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;
> +			}
>  		}
>  		addr += mtd->erasesize;
>  	}

Best regards,
Marek Vasut