Re: [PATCH 5/6] ide: add ata_dev_has_iordy() helper

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Saturday 23 June 2007, Sergei Shtylyov wrote:
> Bartlomiej Zolnierkiewicz wrote:
> 
>     This one is actually arguable...
> 
> > * Add ata_dev_has_iordy() helper.
> 
>     I thought IDE subsys make use of only 'ide_' prefixes. :-)

Nope, see ide-probe.c. ;-)

> > * Use it in sl82c105 host driver so it always gets the correct info
> >   (use_iordy was incorrectly set for "pio" != 255 cases).
> 
>     Hm, why incorrectly? ATA specs say PIO3/4 *must* use IORDY flow control, 
> IIRC... :-/
>     Maybe you meant the mode is being later adjusted by max_mode thereshold -- 
> well, that's a common issue in ide_get_best_pio_mode().

Well, yes but as I think about it now it is non-issue
(all ide_get_best_pio_mode() users support PIO3).

Fixed.

> > * Remove no longer needed ide_pio_data_t.use_iordy field.
> 
> > Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> 
> > Index: b/drivers/ide/ide-lib.c
> > ===================================================================
> > --- a/drivers/ide/ide-lib.c
> > +++ b/drivers/ide/ide-lib.c
> > @@ -267,18 +267,15 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
> >  {
> >  	int pio_mode;
> >  	int cycle_time = 0;
> > -	int use_iordy = 0;
> >  	struct hd_driveid* id = drive->id;
> >  	int overridden  = 0;
> >  
> >  	if (mode_wanted != 255) {
> >  		pio_mode = mode_wanted;
> > -		use_iordy = (pio_mode > 2);
> >  	} else if (!drive->id) {
> >  		pio_mode = 0;
> >  	} else if ((pio_mode = ide_scan_pio_blacklist(id->model)) != -1) {
> >  		printk(KERN_INFO "%s: is on PIO blacklist\n", drive->name);
> > -		use_iordy = (pio_mode > 2);
> >  	} else {
> >  		pio_mode = id->tPIO;
> >  		if (pio_mode > 2) {	/* 2 is maximum allowed tPIO value */
> > @@ -287,7 +284,6 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
> >  		}
> >  		if (id->field_valid & 2) {	  /* drive implements ATA2? */
> >  			if (id->capability & 8) { /* drive supports use_iordy? */
> 
>     The comment above needs fixing too -- kill reference to use_iordy.

Done.

> > -				use_iordy = 1;
> >  				cycle_time = id->eide_pio_iordy;
> >  				if (id->eide_pio_modes & 7) {
> >  					overridden = 0;
> > @@ -325,7 +321,6 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
> >  	if (d) {
> >  		d->pio_mode = pio_mode;
> >  		d->cycle_time = cycle_time ? cycle_time : ide_pio_timings[pio_mode].cycle_time;
> > -		d->use_iordy = use_iordy;
> >  	}
> >  	return pio_mode;
> >  }
> > Index: b/drivers/ide/pci/sl82c105.c
> > ===================================================================
> > --- a/drivers/ide/pci/sl82c105.c
> > +++ b/drivers/ide/pci/sl82c105.c
> > @@ -52,9 +52,10 @@
> >   * Convert a PIO mode and cycle time to the required on/off times
> >   * for the interface.  This has protection against runaway timings.
> >   */
> > -static unsigned int get_pio_timings(ide_pio_data_t *p)
> > +static unsigned int get_pio_timings(ide_drive_t *drive, ide_pio_data_t *p)
> >  {
> >  	unsigned int cmd_on, cmd_off;
> > +	u8 iordy = 0;
> >  
> >  	cmd_on  = (ide_pio_timings[p->pio_mode].active_time + 29) / 30;
> >  	cmd_off = (p->cycle_time - 30 * cmd_on + 29) / 30;
> > @@ -65,7 +66,10 @@ static unsigned int get_pio_timings(ide_
> >  	if (cmd_off == 0)
> >  		cmd_off = 1;
> >  
> > -	return (cmd_on - 1) << 8 | (cmd_off - 1) | (p->use_iordy ? 0x40 : 0x00);
> > +	if (p->pio_mode > 2 || ata_dev_has_iordy(drive->id))
> > +		iordy = 0x40;
> 
>     This logic, although mimicking the old one from ide_get_best_pio_mode(), 
> is not quite correct. As have been noted before, when you set a PIO mode using 
> Set Transfer Mode subcode of the Set Features command, you're always selecting 
> the flow control mode, i.e. using IORDY. So, the last condition in this if 

Oh yes, I keep forgetting about it - some nice FIXME comment
in <linux/ata.h> would be of a great help. :-)

> stmt should probably be the first, if not the sole one...

Fixed, new patch below.

[PATCH] ide: add ata_dev_has_iordy() helper (take 2)

* Add ata_dev_has_iordy() helper and use it sl82c105 host driver.

* Remove no longer needed ide_pio_data_t.use_iordy field.

v2:
* Fix issues noticed by Sergei:
  - correct patch description
  - remove stale comment from ide_get_best_pio_mode()
  - use only ata_dev_has_iordy() in sl82c105 host driver

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
---
 drivers/ide/ide-lib.c      |    7 +------
 drivers/ide/pci/sl82c105.c |   10 +++++++---
 include/linux/ide.h        |    6 +++++-
 3 files changed, 13 insertions(+), 10 deletions(-)

Index: b/drivers/ide/ide-lib.c
===================================================================
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -267,18 +267,15 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
 {
 	int pio_mode;
 	int cycle_time = 0;
-	int use_iordy = 0;
 	struct hd_driveid* id = drive->id;
 	int overridden  = 0;
 
 	if (mode_wanted != 255) {
 		pio_mode = mode_wanted;
-		use_iordy = (pio_mode > 2);
 	} else if (!drive->id) {
 		pio_mode = 0;
 	} else if ((pio_mode = ide_scan_pio_blacklist(id->model)) != -1) {
 		printk(KERN_INFO "%s: is on PIO blacklist\n", drive->name);
-		use_iordy = (pio_mode > 2);
 	} else {
 		pio_mode = id->tPIO;
 		if (pio_mode > 2) {	/* 2 is maximum allowed tPIO value */
@@ -286,8 +283,7 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
 			overridden = 1;
 		}
 		if (id->field_valid & 2) {	  /* drive implements ATA2? */
-			if (id->capability & 8) { /* drive supports use_iordy? */
-				use_iordy = 1;
+			if (id->capability & 8) {
 				cycle_time = id->eide_pio_iordy;
 				if (id->eide_pio_modes & 7) {
 					overridden = 0;
@@ -325,7 +321,6 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
 	if (d) {
 		d->pio_mode = pio_mode;
 		d->cycle_time = cycle_time ? cycle_time : ide_pio_timings[pio_mode].cycle_time;
-		d->use_iordy = use_iordy;
 	}
 	return pio_mode;
 }
Index: b/drivers/ide/pci/sl82c105.c
===================================================================
--- a/drivers/ide/pci/sl82c105.c
+++ b/drivers/ide/pci/sl82c105.c
@@ -52,9 +52,10 @@
  * Convert a PIO mode and cycle time to the required on/off times
  * for the interface.  This has protection against runaway timings.
  */
-static unsigned int get_pio_timings(ide_pio_data_t *p)
+static unsigned int get_pio_timings(ide_drive_t *drive, ide_pio_data_t *p)
 {
 	unsigned int cmd_on, cmd_off;
+	u8 iordy = 0;
 
 	cmd_on  = (ide_pio_timings[p->pio_mode].active_time + 29) / 30;
 	cmd_off = (p->cycle_time - 30 * cmd_on + 29) / 30;
@@ -65,7 +66,10 @@ static unsigned int get_pio_timings(ide_
 	if (cmd_off == 0)
 		cmd_off = 1;
 
-	return (cmd_on - 1) << 8 | (cmd_off - 1) | (p->use_iordy ? 0x40 : 0x00);
+	if (ata_dev_has_iordy(drive->id))
+		iordy = 0x40;
+
+	return (cmd_on - 1) << 8 | (cmd_off - 1) | iordy;
 }
 
 /*
@@ -82,7 +86,7 @@ static u8 sl82c105_tune_pio(ide_drive_t 
 
 	pio = ide_get_best_pio_mode(drive, pio, 5, &p);
 
-	drv_ctrl = get_pio_timings(&p);
+	drv_ctrl = get_pio_timings(drive, &p);
 
 	/*
 	 * Store the PIO timings so that we can restore them
Index: b/include/linux/ide.h
===================================================================
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1363,6 +1363,11 @@ extern void ide_toggle_bounce(ide_drive_
 extern int ide_set_xfer_rate(ide_drive_t *drive, u8 rate);
 int ide_use_fast_pio(ide_drive_t *);
 
+static inline int ata_dev_has_iordy(struct hd_driveid *id)
+{
+	return ((id->field_valid & 2) && (id->capability & 8)) ? 1 : 0;
+}
+
 u8 ide_dump_status(ide_drive_t *, const char *, u8);
 
 typedef struct ide_pio_timings_s {
@@ -1374,7 +1379,6 @@ typedef struct ide_pio_timings_s {
 
 typedef struct ide_pio_data_s {
 	u8 pio_mode;
-	u8 use_iordy;
 	unsigned int cycle_time;
 } ide_pio_data_t;