[PATCH] ata: pata_at91.c bugfix for high master clock

[Sergey Matyukevich]

Hello Igor,

On Sat, 11 Dec 2010 06:37:31 +0300
Igor Plyatov <plyatov at gmail.com> wrote:

> The AT91SAM9 microcontrollers with master clock higher then 105 MHz
> and PIO0, have overflow of the NCS_RD_PULSE value in the MSB. This
> lead to "NCS_RD_PULSE" pulse longer then "NRD_CYCLE" pulse and
> pata_at91 driver does not detect ATA device.
> 
> Signed-off-by: Igor Plyatov <plyatov at gmail.com>
> ---
>  drivers/ata/pata_at91.c |   11 +++++++++--
>  1 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/pata_at91.c b/drivers/ata/pata_at91.c
> index 0da0dcc..2e189be 100644
> --- a/drivers/ata/pata_at91.c
> +++ b/drivers/ata/pata_at91.c
> @@ -33,12 +33,14 @@
>  
>  
>  #define DRV_NAME "pata_at91"
> -#define DRV_VERSION "0.1"
> +#define DRV_VERSION "0.2"
>  
>  #define CF_IDE_OFFSET	    0x00c00000
>  #define CF_ALT_IDE_OFFSET   0x00e00000
>  #define CF_IDE_RES_SIZE     0x08
>  
> +#define NCS_RD_PULSE_LIMIT  0x3f /* maximal value for pulse
> bitfields */ +
>  struct at91_ide_info {
>  	unsigned long mode;
>  	unsigned int cs;
> @@ -50,7 +52,7 @@ struct at91_ide_info {
>  };
>  
>  static const struct ata_timing initial_timing =
> -	{XFER_PIO_0, 70, 290, 240, 600, 165, 150, 600, 0};
> +	{XFER_PIO_0, 70, 290, 240, 600, 165, 150, 0, 600, 0};
>  
>  static unsigned long calc_mck_cycles(unsigned long ns, unsigned long
> mck_hz) {
> @@ -109,6 +111,11 @@ static void set_smc_timing(struct device *dev,
>  	/* (CS0, CS1, DIR, OE) <= (CFCE1, CFCE2, CFRNW, NCSX)
> timings */ ncs_read_setup = 1;
>  	ncs_read_pulse = read_cycle - 2;
> +	if (ncs_read_pulse > NCS_RD_PULSE_LIMIT) {
> +		ncs_read_pulse = NCS_RD_PULSE_LIMIT;
> +		dev_dbg(dev, "ncs_read_pulse limited to maximal
> value %lu\n",

arguably 'dev_warn' would be better in this case

> +			ncs_read_pulse);
> +	}
>  
>  	/* Write timings same as read timings */
>  	write_cycle = read_cycle;

Thanks for the fix.

By the way, it was not a good idea to send this patch separately to
both lists: linux-ide and linux-arm-kernel. I will ack this patch and
add linux-arm-kernel and other recipients in my reply to your email 
to linux-ide list.

Thanks,
Sergey