Patchwork [v2] ata: pata_at91.c bugfix for high master clock

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Submitter Igor Plyatov
Date Dec. 11, 2010, 8:37 p.m.
Message ID <1292099846-24528-1-git-send-email-plyatov@gmail.com>
Download mbox | patch
Permalink /patch/75210/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Igor Plyatov - Dec. 11, 2010, 8:37 p.m.
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 driver
does not detect ATA device.

Signed-off-by: Igor Plyatov <plyatov@gmail.com>
---
 drivers/ata/pata_at91.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)
Jeff Garzik - Dec. 11, 2010, 10:10 p.m.
On 12/11/2010 03:37 PM, Igor Plyatov 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 driver
> does not detect ATA device.
>
> Signed-off-by: Igor Plyatov<plyatov@gmail.com>

Thanks, queued (absent further comments...)


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Sergei Shtylyov - Dec. 12, 2010, 1:49 p.m.
Hello.

On 11-12-2010 23:37, Igor Plyatov 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 driver
> does not detect ATA device.

> Signed-off-by: Igor Plyatov<plyatov@gmail.com>
[...]

> diff --git a/drivers/ata/pata_at91.c b/drivers/ata/pata_at91.c
> index 0da0dcc..a462405 100644
> --- a/drivers/ata/pata_at91.c
> +++ b/drivers/ata/pata_at91.c
[...]
> @@ -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};

    BTW, you haven't described this in the changelog...

WBR, Sergei
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Igor Plyatov - Dec. 12, 2010, 7:02 p.m.
Dear Sergei,

> Hello.
> 
> On 11-12-2010 23:37, Igor Plyatov 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 driver
> > does not detect ATA device.
> 
> > Signed-off-by: Igor Plyatov<plyatov@gmail.com>
> [...]

Please use more descriptive comments, because it is not clear what you
mean here. Maybe here you just cut a text...
It is so strange to cut such small amount of text and I does not have
any idea why here is "[...]" exists.

> > diff --git a/drivers/ata/pata_at91.c b/drivers/ata/pata_at91.c
> > index 0da0dcc..a462405 100644
> > --- a/drivers/ata/pata_at91.c
> > +++ b/drivers/ata/pata_at91.c
> [...]

The same as above. Nobody are able to read you mind on the distance :-)

> > @@ -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};
> 
>     BTW, you haven't described this in the changelog...

Here is just a typo fixed for the ata_timing structure. This typo does
not have influence on the driver operation, but I do not like to leave
such a negligible problem as it is.

> WBR, Sergei

Best regards!
--
Igor Plyatov

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Sergei Shtylyov - Dec. 13, 2010, 11:02 a.m.
Hello.

On 12-12-2010 22:02, Igor Plyatov 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 driver
>>> does not detect ATA device.
>>
>>> Signed-off-by: Igor Plyatov<plyatov@gmail.com>
>> [...]

> Please use more descriptive comments, because it is not clear what you
> mean here. Maybe here you just cut a text...

    Exactly, this is how I mark the cut out text.

> It is so strange to cut such small amount of text and I does not have
> any idea why here is "[...]" exists.

    Well, it's still better than leaving large patches quoted and uncommented, 
having only one comment at the top, as some people do. :-)

>>> diff --git a/drivers/ata/pata_at91.c b/drivers/ata/pata_at91.c
>>> index 0da0dcc..a462405 100644
>>> --- a/drivers/ata/pata_at91.c
>>> +++ b/drivers/ata/pata_at91.c
>> [...]

> The same as above. Nobody are able to read you mind on the distance :-)

    It's the first time anybody tried to iterpret my [...] marks as comments. :-)

>>> @@ -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};

>>      BTW, you haven't described this in the changelog...

> Here is just a typo fixed for the ata_timing structure. This typo does
> not have influence on the driver operation, but I do not like to leave
> such a negligible problem as it is.

   You at least should have noted that in the changelog. And as the change is 
unrelated to the other changes you're doing, it's a good practice to put it 
into a separate patch.

>> WBR, Sergei

> Best regards!
> --
> Igor Plyatov

WBR, Sergei
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Jeff Garzik - Dec. 24, 2010, 6:30 p.m.
On 12/13/2010 06:02 AM, Sergei Shtylyov wrote:
> On 12-12-2010 22:02, Igor Plyatov wrote:
>>>> 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};
>
>>> BTW, you haven't described this in the changelog...
>
>> Here is just a typo fixed for the ata_timing structure. This typo does
>> not have influence on the driver operation, but I do not like to leave
>> such a negligible problem as it is.
>
> You at least should have noted that in the changelog. And as the change
> is unrelated to the other changes you're doing, it's a good practice to
> put it into a separate patch.

Agreed...


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Patch

diff --git a/drivers/ata/pata_at91.c b/drivers/ata/pata_at91.c
index 0da0dcc..a462405 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_warn(dev, "ncs_read_pulse limited to maximal value %lu\n",
+			ncs_read_pulse);
+	}
 
 	/* Write timings same as read timings */
 	write_cycle = read_cycle;