[PATCH 1/3] [IDE] Add helper __ide_setup_pci_device()

[PATCH 1/3] [IDE] Add helper __ide_setup_pci_device()

[Jeff Garzik]

Like ide_setup_pci_device(), except with additional array argument
'u8 *idx' that permits low-level driver to become aware of its assigned
hwifs.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---
 drivers/ide/setup-pci.c |   17 ++++++++++++-----
 include/linux/ide.h     |    1 +
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/ide/setup-pci.c b/drivers/ide/setup-pci.c
index 02d14bf..4960b9f 100644
--- a/drivers/ide/setup-pci.c
+++ b/drivers/ide/setup-pci.c
@@ -666,12 +666,10 @@ out:
 	return ret;
 }
 
-int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
+int __ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d,
+			   u8 *idx)
 {
-	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
-	int ret;
-
-	ret = do_ide_setup_pci_device(dev, d, &idx[0], 1);
+	int ret = do_ide_setup_pci_device(dev, d, idx, 1);
 
 	if (ret >= 0)
 		ide_device_add(idx);
@@ -679,6 +677,15 @@ int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
 	return ret;
 }
 
+EXPORT_SYMBOL_GPL(__ide_setup_pci_device);
+
+int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
+{
+	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
+
+	return __ide_setup_pci_device(dev, d, &idx[0]);
+}
+
 EXPORT_SYMBOL_GPL(ide_setup_pci_device);
 
 int ide_setup_pci_devices(struct pci_dev *dev1, struct pci_dev *dev2,
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 4ed4777..3404fb9 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1244,6 +1244,7 @@ struct ide_port_info {
 	u8			udma_mask;
 };
 
+int __ide_setup_pci_device(struct pci_dev *, const struct ide_port_info *, u8 *);
 int ide_setup_pci_device(struct pci_dev *, const struct ide_port_info *);
 int ide_setup_pci_devices(struct pci_dev *, struct pci_dev *, const struct ide_port_info *);
 
-- 
1.5.2.4

[PATCH 2/3] drivers/ide/pci/sc1200.c: remove pointless hwif lookup loop

[Jeff Garzik]

Store our hwif indices at probe time, in order to eliminate a needless
and ugly loop across all hwifs, searching for our pci device.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---
 drivers/ide/pci/sc1200.c |   76 +++++++++++++++++++++++++++++++---------------
 1 files changed, 51 insertions(+), 25 deletions(-)

diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
index d2c8b55..17e58d6 100644
--- a/drivers/ide/pci/sc1200.c
+++ b/drivers/ide/pci/sc1200.c
@@ -41,6 +41,8 @@
 #define PCI_CLK_66	0x02
 #define PCI_CLK_33A	0x03
 
+#define SC1200_IFS	4
+
 static unsigned short sc1200_get_pci_clock (void)
 {
 	unsigned char chip_id, silicon_revision;
@@ -261,31 +263,32 @@ static void sc1200_set_pio_mode(ide_drive_t *drive, const u8 pio)
 }
 
 #ifdef CONFIG_PM
-static ide_hwif_t *lookup_pci_dev (ide_hwif_t *prev, struct pci_dev *dev)
-{
-	int	h;
-
-	for (h = 0; h < MAX_HWIFS; h++) {
-		ide_hwif_t *hwif = &ide_hwifs[h];
-		if (prev) {
-			if (hwif == prev)
-				prev = NULL;	// found previous, now look for next match
-		} else {
-			if (hwif && hwif->pci_dev == dev)
-				return hwif;	// found next match
-		}
-	}
-	return NULL;	// not found
-}
-
 typedef struct sc1200_saved_state_s {
 	__u32		regs[4];
 } sc1200_saved_state_t;
 
+static unsigned int pack_hwif_idx(u8 *idx)
+{
+	return	(((unsigned int) idx[0]) << 0) |
+		(((unsigned int) idx[1]) << 8) |
+		(((unsigned int) idx[2]) << 16) |
+		(((unsigned int) idx[3]) << 24);
+}
+
+static ide_hwif_t *sc1200_hwif(struct pci_dev *pdev, unsigned int iface)
+{
+	unsigned int packed_hwifs, idx;
+
+	packed_hwifs = (unsigned long) pci_get_drvdata(pdev);
+	idx = (packed_hwifs >> (iface * 8)) & 0xff;
+
+	return (idx == 0xff) ? NULL : &ide_hwifs[idx];
+}
 
 static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 {
-	ide_hwif_t		*hwif = NULL;
+	ide_hwif_t		*hwif;
+	int			i;
 
 	printk("SC1200: suspend(%u)\n", state.event);
 
@@ -295,9 +298,14 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 		//
 		// Loop over all interfaces that are part of this PCI device:
 		//
-		while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
+		for (i = 0; i < SC1200_IFS; i++) {
 			sc1200_saved_state_t	*ss;
 			unsigned int		basereg, r;
+
+			hwif = sc1200_hwif(dev, i);
+			if (!hwif)
+				continue;
+
 			//
 			// allocate a permanent save area, if not already allocated
 			//
@@ -310,7 +318,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 			}
 			ss = (sc1200_saved_state_t *)hwif->config_data;
 			//
-			// Save timing registers:  this may be unnecessary if 
+			// Save timing registers:  this may be unnecessary if
 			// BIOS also does it
 			//
 			basereg = hwif->channel ? 0x50 : 0x40;
@@ -320,7 +328,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 		}
 	}
 
-	/* You don't need to iterate over disks -- sysfs should have done that for you already */ 
+	/* You don't need to iterate over disks -- sysfs should have done that for you already */
 
 	pci_disable_device(dev);
 	pci_set_power_state(dev, pci_choose_state(dev, state));
@@ -330,7 +338,8 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 
 static int sc1200_resume (struct pci_dev *dev)
 {
-	ide_hwif_t	*hwif = NULL;
+	ide_hwif_t		*hwif;
+	int			i;
 
 	pci_set_power_state(dev, PCI_D0);	// bring chip back from sleep state
 	dev->current_state = PM_EVENT_ON;
@@ -338,9 +347,15 @@ static int sc1200_resume (struct pci_dev *dev)
 	//
 	// loop over all interfaces that are part of this pci device:
 	//
-	while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
+	for (i = 0; i < SC1200_IFS; i++) {
 		unsigned int		basereg, r;
-		sc1200_saved_state_t	*ss = (sc1200_saved_state_t *)hwif->config_data;
+		sc1200_saved_state_t	*ss;
+
+		hwif = sc1200_hwif(dev, i);
+		if (!hwif)
+			continue;
+
+		ss = (sc1200_saved_state_t *)hwif->config_data;
 
 		//
 		// Restore timing registers:  this may be unnecessary if BIOS also does it
@@ -386,7 +401,18 @@ static const struct ide_port_info sc1200_chipset __devinitdata = {
 
 static int __devinit sc1200_init_one(struct pci_dev *dev, const struct pci_device_id *id)
 {
-	return ide_setup_pci_device(dev, &sc1200_chipset);
+	unsigned int packed_hwifs;
+	int rc;
+	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
+
+	rc = __ide_setup_pci_device(dev, &sc1200_chipset, &idx[0]);
+	if (rc)
+		return rc;
+	
+	packed_hwifs = pack_hwif_idx(&idx[0]);
+
+	pci_set_drvdata(dev, (void *)(unsigned long) packed_hwifs);
+	return 0;
 }
 
 static const struct pci_device_id sc1200_pci_tbl[] = {
-- 
1.5.2.4

[PATCH 3/3] drivers/ide/pci/sc1200.c: fix suspend/resume buglets and warnings

[Jeff Garzik]

* We shouldn't bother with dev->current_state, the PCI API functions we
  call manage this for us (and do a far better job at it too).

* Remove pci_set_power_state(dev, PCI_D0) call in resume, as
  pci_enable_device() does the same thing.

* Check pci_enable_device() return value.  If it failed, fail
  the entire resume and avoid programming timings into the [potentially
  dead/asleep] chip.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---
 drivers/ide/pci/sc1200.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
index 17e58d6..10c79a5 100644
--- a/drivers/ide/pci/sc1200.c
+++ b/drivers/ide/pci/sc1200.c
@@ -332,7 +332,6 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 
 	pci_disable_device(dev);
 	pci_set_power_state(dev, pci_choose_state(dev, state));
-	dev->current_state = state.event;
 	return 0;
 }
 
@@ -341,9 +340,10 @@ static int sc1200_resume (struct pci_dev *dev)
 	ide_hwif_t		*hwif;
 	int			i;
 
-	pci_set_power_state(dev, PCI_D0);	// bring chip back from sleep state
-	dev->current_state = PM_EVENT_ON;
-	pci_enable_device(dev);
+	i = pci_enable_device(dev);
+	if (i)
+		return i;
+
 	//
 	// loop over all interfaces that are part of this pci device:
 	//
-- 
1.5.2.4

Re: [PATCH 1/3] [IDE] Add helper __ide_setup_pci_device()

[Bartlomiej Zolnierkiewicz]

[ The last few days were extra busy with pushing previously queued
  IDE bits upstream but I'm back to reviewing the new stuff. ]

Thanks for splitting your patch on smaller chunks.

On Thursday 25 October 2007, Jeff Garzik wrote:
> Like ide_setup_pci_device(), except with additional array argument
> 'u8 *idx' that permits low-level driver to become aware of its assigned
> hwifs.

I would prefer to avoid exporting this information to host drivers
if possible (they shouldn't need to know about higher-layer decisions,
plus this change opens the door for various "creative" abuses).

In case of sc1200 host driver fixes (patches #2-3/3) it should be
possible to remove the need for the below patch and at the same time
simplify sc1200 code further (more details in review of patch #2/2).

> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
> ---
>  drivers/ide/setup-pci.c |   17 ++++++++++++-----
>  include/linux/ide.h     |    1 +
>  2 files changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/ide/setup-pci.c b/drivers/ide/setup-pci.c
> index 02d14bf..4960b9f 100644
> --- a/drivers/ide/setup-pci.c
> +++ b/drivers/ide/setup-pci.c
> @@ -666,12 +666,10 @@ out:
>  	return ret;
>  }
>  
> -int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
> +int __ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d,
> +			   u8 *idx)
>  {
> -	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
> -	int ret;
> -
> -	ret = do_ide_setup_pci_device(dev, d, &idx[0], 1);
> +	int ret = do_ide_setup_pci_device(dev, d, idx, 1);
>  
>  	if (ret >= 0)
>  		ide_device_add(idx);
> @@ -679,6 +677,15 @@ int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
>  	return ret;
>  }
>  
> +EXPORT_SYMBOL_GPL(__ide_setup_pci_device);
> +
> +int ide_setup_pci_device(struct pci_dev *dev, const struct ide_port_info *d)
> +{
> +	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
> +
> +	return __ide_setup_pci_device(dev, d, &idx[0]);
> +}
> +
>  EXPORT_SYMBOL_GPL(ide_setup_pci_device);
>  
>  int ide_setup_pci_devices(struct pci_dev *dev1, struct pci_dev *dev2,
> diff --git a/include/linux/ide.h b/include/linux/ide.h
> index 4ed4777..3404fb9 100644
> --- a/include/linux/ide.h
> +++ b/include/linux/ide.h
> @@ -1244,6 +1244,7 @@ struct ide_port_info {
>  	u8			udma_mask;
>  };
>  
> +int __ide_setup_pci_device(struct pci_dev *, const struct ide_port_info *, u8 *);
>  int ide_setup_pci_device(struct pci_dev *, const struct ide_port_info *);
>  int ide_setup_pci_devices(struct pci_dev *, struct pci_dev *, const struct ide_port_info *);

Re: [PATCH 2/3] drivers/ide/pci/sc1200.c: remove pointless hwif lookup loop

[Bartlomiej Zolnierkiewicz]

On Thursday 25 October 2007, Jeff Garzik wrote:
> Store our hwif indices at probe time, in order to eliminate a needless
> and ugly loop across all hwifs, searching for our pci device.

It seems that we can simplify it even further and remove knowledge about
hwifs altogether from suspend/resume methods.

> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
> ---
>  drivers/ide/pci/sc1200.c |   76 +++++++++++++++++++++++++++++++---------------
>  1 files changed, 51 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
> index d2c8b55..17e58d6 100644
> --- a/drivers/ide/pci/sc1200.c
> +++ b/drivers/ide/pci/sc1200.c
> @@ -41,6 +41,8 @@
>  #define PCI_CLK_66	0x02
>  #define PCI_CLK_33A	0x03
>  
> +#define SC1200_IFS	4
> +
>  static unsigned short sc1200_get_pci_clock (void)
>  {
>  	unsigned char chip_id, silicon_revision;
> @@ -261,31 +263,32 @@ static void sc1200_set_pio_mode(ide_drive_t *drive, const u8 pio)
>  }
>  
>  #ifdef CONFIG_PM
> -static ide_hwif_t *lookup_pci_dev (ide_hwif_t *prev, struct pci_dev *dev)
> -{
> -	int	h;
> -
> -	for (h = 0; h < MAX_HWIFS; h++) {
> -		ide_hwif_t *hwif = &ide_hwifs[h];
> -		if (prev) {
> -			if (hwif == prev)
> -				prev = NULL;	// found previous, now look for next match
> -		} else {
> -			if (hwif && hwif->pci_dev == dev)
> -				return hwif;	// found next match
> -		}
> -	}
> -	return NULL;	// not found
> -}
> -
>  typedef struct sc1200_saved_state_s {
>  	__u32		regs[4];
>  } sc1200_saved_state_t;
>  
> +static unsigned int pack_hwif_idx(u8 *idx)
> +{
> +	return	(((unsigned int) idx[0]) << 0) |
> +		(((unsigned int) idx[1]) << 8) |
> +		(((unsigned int) idx[2]) << 16) |
> +		(((unsigned int) idx[3]) << 24);
> +}
> +
> +static ide_hwif_t *sc1200_hwif(struct pci_dev *pdev, unsigned int iface)
> +{
> +	unsigned int packed_hwifs, idx;
> +
> +	packed_hwifs = (unsigned long) pci_get_drvdata(pdev);
> +	idx = (packed_hwifs >> (iface * 8)) & 0xff;
> +
> +	return (idx == 0xff) ? NULL : &ide_hwifs[idx];
> +}
>  
>  static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>  {
> -	ide_hwif_t		*hwif = NULL;
> +	ide_hwif_t		*hwif;
> +	int			i;
>  
>  	printk("SC1200: suspend(%u)\n", state.event);
>  
> @@ -295,9 +298,14 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>  		//
>  		// Loop over all interfaces that are part of this PCI device:
>  		//
> -		while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
> +		for (i = 0; i < SC1200_IFS; i++) {
>  			sc1200_saved_state_t	*ss;
>  			unsigned int		basereg, r;
> +
> +			hwif = sc1200_hwif(dev, i);
> +			if (!hwif)
> +				continue;
> +
>  			//
>  			// allocate a permanent save area, if not already allocated
>  			//
> @@ -310,7 +318,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>  			}
>  			ss = (sc1200_saved_state_t *)hwif->config_data;
>  			//
> -			// Save timing registers:  this may be unnecessary if 
> +			// Save timing registers:  this may be unnecessary if
>  			// BIOS also does it
>  			//
>  			basereg = hwif->channel ? 0x50 : 0x40;

Please take a close look at the line above and the next three lines:

for (r = 0; r < 4; ++r) {
	pci_read_config_dword (hwif->pci_dev, basereg + (r<<2), &ss->regs[r]);
}

It is highly obfuscated but the sc1200_suspend() reads 16 bytes from
the offset 0x40 (for the primary port) and puts them in the corresponding
struct sc1200_saved_state_s buffer, then it reads another 16 bytes from the
offset 0x50 (for the secondary port) and puts it in the another buffer.

In summary sc1200_suspend() reads 32 continuous bytes from offset 0x40
and the exactly reverse operation happens in sc1200_resume().

Given that and the fact that struct sc1200_save_state_s buffers are used
_only_ by sc1200_{suspend,resume}() we may safely convert the code to use
one buffer for both ports (the whole PCI device).  We just need to bump
the size of struct sc1200_saved_state_s (from 4 to 8 double-words) and use
pci_{get,set}_drvdata() instead of hwif->config_data.  Then we can remove
looping over interfaces completely from sc1200_{suspend,resume}()! :)

> @@ -320,7 +328,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>  		}
>  	}
>  
> -	/* You don't need to iterate over disks -- sysfs should have done that for you already */ 
> +	/* You don't need to iterate over disks -- sysfs should have done that for you already */
>  
>  	pci_disable_device(dev);
>  	pci_set_power_state(dev, pci_choose_state(dev, state));
> @@ -330,7 +338,8 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>  
>  static int sc1200_resume (struct pci_dev *dev)
>  {
> -	ide_hwif_t	*hwif = NULL;
> +	ide_hwif_t		*hwif;
> +	int			i;
>  
>  	pci_set_power_state(dev, PCI_D0);	// bring chip back from sleep state
>  	dev->current_state = PM_EVENT_ON;
> @@ -338,9 +347,15 @@ static int sc1200_resume (struct pci_dev *dev)
>  	//
>  	// loop over all interfaces that are part of this pci device:
>  	//
> -	while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
> +	for (i = 0; i < SC1200_IFS; i++) {
>  		unsigned int		basereg, r;
> -		sc1200_saved_state_t	*ss = (sc1200_saved_state_t *)hwif->config_data;
> +		sc1200_saved_state_t	*ss;
> +
> +		hwif = sc1200_hwif(dev, i);
> +		if (!hwif)
> +			continue;
> +
> +		ss = (sc1200_saved_state_t *)hwif->config_data;
>  
>  		//
>  		// Restore timing registers:  this may be unnecessary if BIOS also does it
> @@ -386,7 +401,18 @@ static const struct ide_port_info sc1200_chipset __devinitdata = {
>  
>  static int __devinit sc1200_init_one(struct pci_dev *dev, const struct pci_device_id *id)
>  {
> -	return ide_setup_pci_device(dev, &sc1200_chipset);
> +	unsigned int packed_hwifs;
> +	int rc;
> +	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
> +
> +	rc = __ide_setup_pci_device(dev, &sc1200_chipset, &idx[0]);
> +	if (rc)
> +		return rc;
> +	
> +	packed_hwifs = pack_hwif_idx(&idx[0]);
> +
> +	pci_set_drvdata(dev, (void *)(unsigned long) packed_hwifs);
> +	return 0;
>  }
>  
>  static const struct pci_device_id sc1200_pci_tbl[] = {

Re: [PATCH 3/3] drivers/ide/pci/sc1200.c: fix suspend/resume buglets and warnings

[Bartlomiej Zolnierkiewicz]

On Thursday 25 October 2007, Jeff Garzik wrote:
> * We shouldn't bother with dev->current_state, the PCI API functions we
>   call manage this for us (and do a far better job at it too).
> 
> * Remove pci_set_power_state(dev, PCI_D0) call in resume, as
>   pci_enable_device() does the same thing.
> 
> * Check pci_enable_device() return value.  If it failed, fail
>   the entire resume and avoid programming timings into the [potentially
>   dead/asleep] chip.
> 
> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

applied, thanks

Re: [PATCH 2/3] drivers/ide/pci/sc1200.c: remove pointless hwif lookup loop

[Jeff Garzik]

Bartlomiej Zolnierkiewicz wrote:
> On Thursday 25 October 2007, Jeff Garzik wrote:
>> Store our hwif indices at probe time, in order to eliminate a needless
>> and ugly loop across all hwifs, searching for our pci device.
> 
> It seems that we can simplify it even further and remove knowledge about
> hwifs altogether from suspend/resume methods.
> 
>> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
>> ---
>>  drivers/ide/pci/sc1200.c |   76 +++++++++++++++++++++++++++++++---------------
>>  1 files changed, 51 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
>> index d2c8b55..17e58d6 100644
>> --- a/drivers/ide/pci/sc1200.c
>> +++ b/drivers/ide/pci/sc1200.c
>> @@ -41,6 +41,8 @@
>>  #define PCI_CLK_66	0x02
>>  #define PCI_CLK_33A	0x03
>>  
>> +#define SC1200_IFS	4
>> +
>>  static unsigned short sc1200_get_pci_clock (void)
>>  {
>>  	unsigned char chip_id, silicon_revision;
>> @@ -261,31 +263,32 @@ static void sc1200_set_pio_mode(ide_drive_t *drive, const u8 pio)
>>  }
>>  
>>  #ifdef CONFIG_PM
>> -static ide_hwif_t *lookup_pci_dev (ide_hwif_t *prev, struct pci_dev *dev)
>> -{
>> -	int	h;
>> -
>> -	for (h = 0; h < MAX_HWIFS; h++) {
>> -		ide_hwif_t *hwif = &ide_hwifs[h];
>> -		if (prev) {
>> -			if (hwif == prev)
>> -				prev = NULL;	// found previous, now look for next match
>> -		} else {
>> -			if (hwif && hwif->pci_dev == dev)
>> -				return hwif;	// found next match
>> -		}
>> -	}
>> -	return NULL;	// not found
>> -}
>> -
>>  typedef struct sc1200_saved_state_s {
>>  	__u32		regs[4];
>>  } sc1200_saved_state_t;
>>  
>> +static unsigned int pack_hwif_idx(u8 *idx)
>> +{
>> +	return	(((unsigned int) idx[0]) << 0) |
>> +		(((unsigned int) idx[1]) << 8) |
>> +		(((unsigned int) idx[2]) << 16) |
>> +		(((unsigned int) idx[3]) << 24);
>> +}
>> +
>> +static ide_hwif_t *sc1200_hwif(struct pci_dev *pdev, unsigned int iface)
>> +{
>> +	unsigned int packed_hwifs, idx;
>> +
>> +	packed_hwifs = (unsigned long) pci_get_drvdata(pdev);
>> +	idx = (packed_hwifs >> (iface * 8)) & 0xff;
>> +
>> +	return (idx == 0xff) ? NULL : &ide_hwifs[idx];
>> +}
>>  
>>  static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>>  {
>> -	ide_hwif_t		*hwif = NULL;
>> +	ide_hwif_t		*hwif;
>> +	int			i;
>>  
>>  	printk("SC1200: suspend(%u)\n", state.event);
>>  
>> @@ -295,9 +298,14 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>>  		//
>>  		// Loop over all interfaces that are part of this PCI device:
>>  		//
>> -		while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
>> +		for (i = 0; i < SC1200_IFS; i++) {
>>  			sc1200_saved_state_t	*ss;
>>  			unsigned int		basereg, r;
>> +
>> +			hwif = sc1200_hwif(dev, i);
>> +			if (!hwif)
>> +				continue;
>> +
>>  			//
>>  			// allocate a permanent save area, if not already allocated
>>  			//
>> @@ -310,7 +318,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
>>  			}
>>  			ss = (sc1200_saved_state_t *)hwif->config_data;
>>  			//
>> -			// Save timing registers:  this may be unnecessary if 
>> +			// Save timing registers:  this may be unnecessary if
>>  			// BIOS also does it
>>  			//
>>  			basereg = hwif->channel ? 0x50 : 0x40;
> 
> Please take a close look at the line above and the next three lines:
> 
> for (r = 0; r < 4; ++r) {
> 	pci_read_config_dword (hwif->pci_dev, basereg + (r<<2), &ss->regs[r]);
> }
> 
> It is highly obfuscated but the sc1200_suspend() reads 16 bytes from
> the offset 0x40 (for the primary port) and puts them in the corresponding
> struct sc1200_saved_state_s buffer, then it reads another 16 bytes from the
> offset 0x50 (for the secondary port) and puts it in the another buffer.
> 
> In summary sc1200_suspend() reads 32 continuous bytes from offset 0x40
> and the exactly reverse operation happens in sc1200_resume().
> 
> Given that and the fact that struct sc1200_save_state_s buffers are used
> _only_ by sc1200_{suspend,resume}() we may safely convert the code to use
> one buffer for both ports (the whole PCI device).  We just need to bump
> the size of struct sc1200_saved_state_s (from 4 to 8 double-words) and use
> pci_{get,set}_drvdata() instead of hwif->config_data.  Then we can remove
> looping over interfaces completely from sc1200_{suspend,resume}()! :)

May I assume you'll handle that task?  :)  It sounds like you have a far 
better idea than mine, and my main goal -- fixing bugs and warning -- is 
accomplished anyway with the merging of patch #3.

	Jeff

Re: [PATCH 2/3] drivers/ide/pci/sc1200.c: remove pointless hwif lookup loop

[Bartlomiej Zolnierkiewicz]

On Friday 26 October 2007, Jeff Garzik wrote:
> Bartlomiej Zolnierkiewicz wrote:
> > On Thursday 25 October 2007, Jeff Garzik wrote:
> >> Store our hwif indices at probe time, in order to eliminate a needless
> >> and ugly loop across all hwifs, searching for our pci device.
> > 
> > It seems that we can simplify it even further and remove knowledge about
> > hwifs altogether from suspend/resume methods.
> > 
> >> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
> >> ---
> >>  drivers/ide/pci/sc1200.c |   76 +++++++++++++++++++++++++++++++---------------
> >>  1 files changed, 51 insertions(+), 25 deletions(-)
> >>
> >> diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
> >> index d2c8b55..17e58d6 100644
> >> --- a/drivers/ide/pci/sc1200.c
> >> +++ b/drivers/ide/pci/sc1200.c
> >> @@ -41,6 +41,8 @@
> >>  #define PCI_CLK_66	0x02
> >>  #define PCI_CLK_33A	0x03
> >>  
> >> +#define SC1200_IFS	4
> >> +
> >>  static unsigned short sc1200_get_pci_clock (void)
> >>  {
> >>  	unsigned char chip_id, silicon_revision;
> >> @@ -261,31 +263,32 @@ static void sc1200_set_pio_mode(ide_drive_t *drive, const u8 pio)
> >>  }
> >>  
> >>  #ifdef CONFIG_PM
> >> -static ide_hwif_t *lookup_pci_dev (ide_hwif_t *prev, struct pci_dev *dev)
> >> -{
> >> -	int	h;
> >> -
> >> -	for (h = 0; h < MAX_HWIFS; h++) {
> >> -		ide_hwif_t *hwif = &ide_hwifs[h];
> >> -		if (prev) {
> >> -			if (hwif == prev)
> >> -				prev = NULL;	// found previous, now look for next match
> >> -		} else {
> >> -			if (hwif && hwif->pci_dev == dev)
> >> -				return hwif;	// found next match
> >> -		}
> >> -	}
> >> -	return NULL;	// not found
> >> -}
> >> -
> >>  typedef struct sc1200_saved_state_s {
> >>  	__u32		regs[4];
> >>  } sc1200_saved_state_t;
> >>  
> >> +static unsigned int pack_hwif_idx(u8 *idx)
> >> +{
> >> +	return	(((unsigned int) idx[0]) << 0) |
> >> +		(((unsigned int) idx[1]) << 8) |
> >> +		(((unsigned int) idx[2]) << 16) |
> >> +		(((unsigned int) idx[3]) << 24);
> >> +}
> >> +
> >> +static ide_hwif_t *sc1200_hwif(struct pci_dev *pdev, unsigned int iface)
> >> +{
> >> +	unsigned int packed_hwifs, idx;
> >> +
> >> +	packed_hwifs = (unsigned long) pci_get_drvdata(pdev);
> >> +	idx = (packed_hwifs >> (iface * 8)) & 0xff;
> >> +
> >> +	return (idx == 0xff) ? NULL : &ide_hwifs[idx];
> >> +}
> >>  
> >>  static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
> >>  {
> >> -	ide_hwif_t		*hwif = NULL;
> >> +	ide_hwif_t		*hwif;
> >> +	int			i;
> >>  
> >>  	printk("SC1200: suspend(%u)\n", state.event);
> >>  
> >> @@ -295,9 +298,14 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
> >>  		//
> >>  		// Loop over all interfaces that are part of this PCI device:
> >>  		//
> >> -		while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
> >> +		for (i = 0; i < SC1200_IFS; i++) {
> >>  			sc1200_saved_state_t	*ss;
> >>  			unsigned int		basereg, r;
> >> +
> >> +			hwif = sc1200_hwif(dev, i);
> >> +			if (!hwif)
> >> +				continue;
> >> +
> >>  			//
> >>  			// allocate a permanent save area, if not already allocated
> >>  			//
> >> @@ -310,7 +318,7 @@ static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
> >>  			}
> >>  			ss = (sc1200_saved_state_t *)hwif->config_data;
> >>  			//
> >> -			// Save timing registers:  this may be unnecessary if 
> >> +			// Save timing registers:  this may be unnecessary if
> >>  			// BIOS also does it
> >>  			//
> >>  			basereg = hwif->channel ? 0x50 : 0x40;
> > 
> > Please take a close look at the line above and the next three lines:
> > 
> > for (r = 0; r < 4; ++r) {
> > 	pci_read_config_dword (hwif->pci_dev, basereg + (r<<2), &ss->regs[r]);
> > }
> > 
> > It is highly obfuscated but the sc1200_suspend() reads 16 bytes from
> > the offset 0x40 (for the primary port) and puts them in the corresponding
> > struct sc1200_saved_state_s buffer, then it reads another 16 bytes from the
> > offset 0x50 (for the secondary port) and puts it in the another buffer.
> > 
> > In summary sc1200_suspend() reads 32 continuous bytes from offset 0x40
> > and the exactly reverse operation happens in sc1200_resume().
> > 
> > Given that and the fact that struct sc1200_save_state_s buffers are used
> > _only_ by sc1200_{suspend,resume}() we may safely convert the code to use
> > one buffer for both ports (the whole PCI device).  We just need to bump
> > the size of struct sc1200_saved_state_s (from 4 to 8 double-words) and use
> > pci_{get,set}_drvdata() instead of hwif->config_data.  Then we can remove
> > looping over interfaces completely from sc1200_{suspend,resume}()! :)
> 
> May I assume you'll handle that task?  :)  It sounds like you have a far 
> better idea than mine, and my main goal -- fixing bugs and warning -- is 
> accomplished anyway with the merging of patch #3.

Uh, OK...

[PATCH] sc1200: remove pointless hwif lookup loop

Save PCI regs values for both IDE ports in one buffer, in order to eliminate
a needless and ugly loop across all hwifs, searching for our PCI device.

Partially based on the previous patch by Jeff Garzik.

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
 drivers/ide/pci/sc1200.c |  106 ++++++++++++++++-------------------------------
 1 file changed, 37 insertions(+), 69 deletions(-)

Index: b/drivers/ide/pci/sc1200.c
===================================================================
--- a/drivers/ide/pci/sc1200.c
+++ b/drivers/ide/pci/sc1200.c
@@ -261,66 +261,39 @@ static void sc1200_set_pio_mode(ide_driv
 }
 
 #ifdef CONFIG_PM
-static ide_hwif_t *lookup_pci_dev (ide_hwif_t *prev, struct pci_dev *dev)
-{
-	int	h;
-
-	for (h = 0; h < MAX_HWIFS; h++) {
-		ide_hwif_t *hwif = &ide_hwifs[h];
-		if (prev) {
-			if (hwif == prev)
-				prev = NULL;	// found previous, now look for next match
-		} else {
-			if (hwif && hwif->pci_dev == dev)
-				return hwif;	// found next match
-		}
-	}
-	return NULL;	// not found
-}
-
-typedef struct sc1200_saved_state_s {
-	__u32		regs[4];
-} sc1200_saved_state_t;
-
+struct sc1200_saved_state {
+	u32 regs[8];
+};
 
 static int sc1200_suspend (struct pci_dev *dev, pm_message_t state)
 {
-	ide_hwif_t		*hwif = NULL;
-
 	printk("SC1200: suspend(%u)\n", state.event);
 
+	/*
+	 * we only save state when going from full power to less
+	 */
 	if (state.event == PM_EVENT_ON) {
-		// we only save state when going from full power to less
+		struct sc1200_saved_state *ss;
+		unsigned int r;
 
-		//
-		// Loop over all interfaces that are part of this PCI device:
-		//
-		while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
-			sc1200_saved_state_t	*ss;
-			unsigned int		basereg, r;
-			//
-			// allocate a permanent save area, if not already allocated
-			//
-			ss = (sc1200_saved_state_t *)hwif->config_data;
-			if (ss == NULL) {
-				ss = kmalloc(sizeof(sc1200_saved_state_t), GFP_KERNEL);
-				if (ss == NULL)
-					return -ENOMEM;
-				hwif->config_data = (unsigned long)ss;
-			}
-			ss = (sc1200_saved_state_t *)hwif->config_data;
-			//
-			// Save timing registers:  this may be unnecessary if 
-			// BIOS also does it
-			//
-			basereg = hwif->channel ? 0x50 : 0x40;
-			for (r = 0; r < 4; ++r) {
-				pci_read_config_dword (hwif->pci_dev, basereg + (r<<2), &ss->regs[r]);
-			}
+		/*
+		 * allocate a permanent save area, if not already allocated
+		 */
+		ss = (struct sc1200_saved_state *)pci_get_drvdata(dev);
+		if (ss == NULL) {
+			ss = kmalloc(sizeof(*ss), GFP_KERNEL);
+			if (ss == NULL)
+				return -ENOMEM;
+			pci_set_drvdata(dev, ss);
 		}
-	}
 
-	/* You don't need to iterate over disks -- sysfs should have done that for you already */ 
+		/*
+		 * save timing registers
+		 * (this may be unnecessary if BIOS also does it)
+		 */
+		for (r = 0; r < 8; r++)
+			pci_read_config_dword(dev, 0x40 + r * 4, &ss->regs[r]);
+	}
 
 	pci_disable_device(dev);
 	pci_set_power_state(dev, pci_choose_state(dev, state));
@@ -329,30 +302,25 @@ static int sc1200_suspend (struct pci_de
 
 static int sc1200_resume (struct pci_dev *dev)
 {
-	ide_hwif_t	*hwif = NULL;
-	int		i;
+	struct sc1200_saved_state *ss;
+	unsigned int r;
+	int i;
 
 	i = pci_enable_device(dev);
 	if (i)
 		return i;
 
-	//
-	// loop over all interfaces that are part of this pci device:
-	//
-	while ((hwif = lookup_pci_dev(hwif, dev)) != NULL) {
-		unsigned int		basereg, r;
-		sc1200_saved_state_t	*ss = (sc1200_saved_state_t *)hwif->config_data;
-
-		//
-		// Restore timing registers:  this may be unnecessary if BIOS also does it
-		//
-		basereg = hwif->channel ? 0x50 : 0x40;
-		if (ss != NULL) {
-			for (r = 0; r < 4; ++r) {
-				pci_write_config_dword(hwif->pci_dev, basereg + (r<<2), ss->regs[r]);
-			}
-		}
+	ss = (struct sc1200_saved_state *)pci_get_drvdata(dev);
+
+	/*
+	 * restore timing registers
+	 * (this may be unnecessary if BIOS also does it)
+	 */
+	if (ss) {
+		for (r = 0; r < 8; r++)
+			pci_write_config_dword(dev, 0x40 + r * 4, ss->regs[r]);
 	}
+
 	return 0;
 }
 #endif