Re: [PATCH v3 5/8] MTD: xway: fix nand locking

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Sun, 19 Jun 2016 18:08:14 +0200
Hauke Mehrtens <hauke@hauke-m.de> wrote:

> From: John Crispin <john@phrozen.org>
> 
> The external Bus Unit (EBU) can control different flash devices, but
> these NAND flash commands have to be atomic and should not be
> interrupted in between. Lock the EBU from the beginning of the command
> till the end by moving the lock to the chip select.
> 
> Signed-off-by: John Crispin <john@phrozen.org>
> Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
> ---
>  drivers/mtd/nand/xway_nand.c | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
> index 8a0019a..618cf34 100644
> --- a/drivers/mtd/nand/xway_nand.c
> +++ b/drivers/mtd/nand/xway_nand.c
> @@ -65,17 +65,22 @@
>  
>  struct xway_nand_data {
>  	struct nand_chip	chip;
> +	unsigned long		csflags;
>  };
>  
> -static void xway_select_chip(struct mtd_info *mtd, int chip)
> +static void xway_select_chip(struct mtd_info *mtd, int select)
>  {
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct xway_nand_data *data = nand_get_controller_data(chip);
>  
> -	switch (chip) {
> +	switch (select) {
>  	case -1:
>  		ltq_ebu_w32_mask(NAND_CON_CE, 0, EBU_NAND_CON);
>  		ltq_ebu_w32_mask(NAND_CON_NANDM, 0, EBU_NAND_CON);
> +		spin_unlock_irqrestore(&ebu_lock, data->csflags);
>  		break;
>  	case 0:
> +		spin_lock_irqsave(&ebu_lock, data->csflags);
>  		ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON);
>  		ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON);
>  		break;
> @@ -88,12 +93,10 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
>  {
>  	struct nand_chip *this = mtd_to_nand(mtd);
>  	unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
> -	unsigned long flags;
>  
>  	if (cmd == NAND_CMD_NONE)
>  		return;
>  
> -	spin_lock_irqsave(&ebu_lock, flags);
>  	if (ctrl & NAND_CLE)
>  		writeb(cmd, (void __iomem *) (nandaddr | NAND_WRITE_CMD));
>  	else if (ctrl & NAND_ALE)
> @@ -101,7 +104,6 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
>  
>  	while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
>  		;
> -	spin_unlock_irqrestore(&ebu_lock, flags);
>  }
>  
>  static int xway_dev_ready(struct mtd_info *mtd)
> @@ -113,14 +115,8 @@ static unsigned char xway_read_byte(struct mtd_info *mtd)
>  {
>  	struct nand_chip *this = mtd_to_nand(mtd);
>  	unsigned long nandaddr = (unsigned long) this->IO_ADDR_R;
> -	unsigned long flags;
> -	int ret;
>  
> -	spin_lock_irqsave(&ebu_lock, flags);
> -	ret = ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));
> -	spin_unlock_irqrestore(&ebu_lock, flags);
> -
> -	return ret;
> +	return ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));

	Drop the cast and use this->IO_ADDR_R here.

>  }
>  
>  /*