[PATCH v2] ssb: do not read SPROM if it does not exist

[PATCH v2] ssb: do not read SPROM if it does not exist

[John W. Linville]

Attempting to read registers that don't exist on the SSB bus can cause
hangs on some boxes.  At least some b43 devices are 'in the wild' that
don't have SPROMs at all.  When the SSB bus support loads, it attempts
to read these (non-existant) SPROMs and causes hard hangs on the box --
no console output, etc.

This patch adds some intelligence to determine whether or not the SPROM
is present before attempting to read it.  This avoids those hard hangs
on those devices with no SPROM attached to their SSB bus.  The
SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
will survive to test further patches. :-)

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: stable@kernel.org
---
Version 2, check the correct place for ChipCommon core revision... :-)

 drivers/ssb/pci.c                         |    3 +++
 drivers/ssb/scan.c                        |    4 ++++
 drivers/ssb/sprom.c                       |   22 ++++++++++++++++++++++
 include/linux/ssb/ssb.h                   |    3 +++
 include/linux/ssb/ssb_driver_chipcommon.h |   15 +++++++++++++++
 5 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
index 9e50896..2f7b16d 100644
--- a/drivers/ssb/pci.c
+++ b/drivers/ssb/pci.c
@@ -620,6 +620,9 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
 	int err = -ENOMEM;
 	u16 *buf;
 
+	if (!ssb_is_sprom_available(bus))
+		return -ENODEV;
+
 	buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
 	if (!buf)
 		goto out;
diff --git a/drivers/ssb/scan.c b/drivers/ssb/scan.c
index 0d6c028..c4944b9 100644
--- a/drivers/ssb/scan.c
+++ b/drivers/ssb/scan.c
@@ -306,6 +306,10 @@ int ssb_bus_scan(struct ssb_bus *bus,
 		}
 		tmp = scan_read32(bus, 0, SSB_CHIPCO_CAP);
 		bus->chipco.capabilities = tmp;
+		if (bus->chipco.dev->id.revision >= 11)
+			tmp = scan_read32(bus, 0, SSB_CHIPCO_CHIPSTAT);
+			bus->chipco.status = tmp;
+		}
 	} else {
 		if (bus->bustype == SSB_BUSTYPE_PCI) {
 			bus->chip_id = pcidev_to_chipid(bus->host_pci);
diff --git a/drivers/ssb/sprom.c b/drivers/ssb/sprom.c
index d0e6762..55eb9b0 100644
--- a/drivers/ssb/sprom.c
+++ b/drivers/ssb/sprom.c
@@ -175,3 +175,25 @@ const struct ssb_sprom *ssb_get_fallback_sprom(void)
 {
 	return fallback_sprom;
 }
+
+bool ssb_is_sprom_available(struct ssb_bus *bus)
+{
+	/* status register only exists on chipcomon rev >= 11 */
+	if (bus->chipco.dev->id.revision < 11)
+		return true;
+
+	switch (bus->chip_id) {
+	case 0x4312:
+		return SSB_CHIPCO_CHST_4312_SPROM_PRESENT(bus->chipco.status);
+	case 0x4322:
+		return SSB_CHIPCO_CHST_4322_SPROM_PRESENT(bus->chipco.status);
+	case 0x4325:
+		return SSB_CHIPCO_CHST_4325_SPROM_PRESENT(bus->chipco.status);
+	default:
+		break;
+	}
+	if (bus->chipco.dev->id.revision >= 31)
+		return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
+
+	return true;
+}
diff --git a/include/linux/ssb/ssb.h b/include/linux/ssb/ssb.h
index 24f9885..3b4da23 100644
--- a/include/linux/ssb/ssb.h
+++ b/include/linux/ssb/ssb.h
@@ -394,6 +394,9 @@ extern int ssb_bus_sdiobus_register(struct ssb_bus *bus,
 
 extern void ssb_bus_unregister(struct ssb_bus *bus);
 
+/* Does the device have an SPROM? */
+extern bool ssb_is_sprom_available(struct ssb_bus *bus);
+
 /* Set a fallback SPROM.
  * See kdoc at the function definition for complete documentation. */
 extern int ssb_arch_set_fallback_sprom(const struct ssb_sprom *sprom);
diff --git a/include/linux/ssb/ssb_driver_chipcommon.h b/include/linux/ssb/ssb_driver_chipcommon.h
index 4e27acf..2cdf249 100644
--- a/include/linux/ssb/ssb_driver_chipcommon.h
+++ b/include/linux/ssb/ssb_driver_chipcommon.h
@@ -53,6 +53,7 @@
 #define  SSB_CHIPCO_CAP_64BIT		0x08000000	/* 64-bit Backplane */
 #define  SSB_CHIPCO_CAP_PMU		0x10000000	/* PMU available (rev >= 20) */
 #define  SSB_CHIPCO_CAP_ECI		0x20000000	/* ECI available (rev >= 20) */
+#define  SSB_CHIPCO_CAP_SPROM		0x40000000	/* SPROM present */
 #define SSB_CHIPCO_CORECTL		0x0008
 #define  SSB_CHIPCO_CORECTL_UARTCLK0	0x00000001	/* Drive UART with internal clock */
 #define	 SSB_CHIPCO_CORECTL_SE		0x00000002	/* sync clk out enable (corerev >= 3) */
@@ -385,6 +386,7 @@
 
 
 /** Chip specific Chip-Status register contents. */
+#define SSB_CHIPCO_CHST_4322_SPROM_EXISTS	0x00000040 /* SPROM present */
 #define SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL	0x00000003
 #define SSB_CHIPCO_CHST_4325_DEFCIS_SEL		0 /* OTP is powered up, use def. CIS, no SPROM */
 #define SSB_CHIPCO_CHST_4325_SPROM_SEL		1 /* OTP is powered up, SPROM is present */
@@ -398,6 +400,18 @@
 #define SSB_CHIPCO_CHST_4325_RCAL_VALUE_SHIFT	4
 #define SSB_CHIPCO_CHST_4325_PMUTOP_2B 		0x00000200 /* 1 for 2b, 0 for to 2a */
 
+/** Macros to determine SPROM presence based on Chip-Status register. */
+#define SSB_CHIPCO_CHST_4312_SPROM_PRESENT(status) \
+	((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_OTP_SEL)
+#define SSB_CHIPCO_CHST_4322_SPROM_PRESENT(status) \
+	(status & SSB_CHIPCO_CHST_4322_SPROM_EXISTS)
+#define SSB_CHIPCO_CHST_4325_SPROM_PRESENT(status) \
+	(((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_DEFCIS_SEL) && \
+	 ((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_OTP_SEL))
+
 
 
 /** Clockcontrol masks and values **/
@@ -564,6 +578,7 @@ struct ssb_chipcommon_pmu {
 struct ssb_chipcommon {
 	struct ssb_device *dev;
 	u32 capabilities;
+	u32 status;
 	/* Fast Powerup Delay constant */
 	u16 fast_pwrup_delay;
 	struct ssb_chipcommon_pmu pmu;
-- 
1.6.2.5

[PATCH V2] ssb: do not read SPROM if it does not exist

[Rafał Miłecki]

Attempting to read registers that don't exist on the SSB bus can cause
hangs on some boxes.  At least some b43 devices are 'in the wild' that
don't have SPROMs at all.  When the SSB bus support loads, it attempts
to read these (non-existant) SPROMs and causes hard hangs on the box --
no console output, etc.

This patch adds some intelligence to determine whether or not the SPROM
is present before attempting to read it.  This avoids those hard hangs
on those devices with no SPROM attached to their SSB bus.  The
SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
will survive to test further patches. :-)

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Michael Buesch <mb@bu3sch.de>
---
V2: adapt to updated specs, drop some warning-causing braces

Do I understand correctly this patch can be applied even without fix for
location of SPROM? AFAIU that is separated issue and we do not support
SPROM with recently discovered location anyway. However this should fix
hangs on boards without SPROM, right?

John: I searched for explaination of Signed-off-by and found info it shows
people involved in creating patch. As this one is mostly based on yours, I
have kept your S-o-b line. Is that OK? Is this also OK I added myself, even
if my involvement is much lower than yours?

Please do not irritate if I done this incorrectly :)

So finally: can someone test this, please? John?
---
 drivers/ssb/driver_chipcommon.c           |    2 +
 drivers/ssb/pci.c                         |    5 ++++
 drivers/ssb/sprom.c                       |   30 +++++++++++++++++++++++++++++
 include/linux/ssb/ssb.h                   |    3 ++
 include/linux/ssb/ssb_driver_chipcommon.h |   15 ++++++++++++++
 5 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/drivers/ssb/driver_chipcommon.c b/drivers/ssb/driver_chipcommon.c
index 59c3c0f..59ae76b 100644
--- a/drivers/ssb/driver_chipcommon.c
+++ b/drivers/ssb/driver_chipcommon.c
@@ -233,6 +233,8 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
 {
 	if (!cc->dev)
 		return; /* We don't have a ChipCommon */
+	if (cc->dev->id.revision >= 11)
+		cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
 	ssb_pmu_init(cc);
 	chipco_powercontrol_init(cc);
 	ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);
diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
index 9e50896..a4b2b99 100644
--- a/drivers/ssb/pci.c
+++ b/drivers/ssb/pci.c
@@ -620,6 +620,11 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
 	int err = -ENOMEM;
 	u16 *buf;
 
+	if (!ssb_is_sprom_available(bus)) {
+		ssb_printk(KERN_ERR PFX "No SPROM available!\n");
+		return -ENODEV;
+	}
+
 	buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
 	if (!buf)
 		goto out;
diff --git a/drivers/ssb/sprom.c b/drivers/ssb/sprom.c
index d0e6762..fbaa68c 100644
--- a/drivers/ssb/sprom.c
+++ b/drivers/ssb/sprom.c
@@ -175,3 +175,33 @@ const struct ssb_sprom *ssb_get_fallback_sprom(void)
 {
 	return fallback_sprom;
 }
+
+bool ssb_is_sprom_available(struct ssb_bus *bus)
+{
+	if (bus->bustype == SSB_BUSTYPE_PCI) {
+		if (bus->chipco.dev->id.revision >= 31)
+			return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
+	} else if (bus->bustype == SSB_BUSTYPE_PCMCIA) {
+		/* status register only exists on chipcomon rev >= 11 */
+		if (bus->chipco.dev->id.revision < 11)
+			return true;
+
+		switch (bus->chip_id) {
+		case 0x4312:
+			return SSB_CHIPCO_CHST_4312_SPROM_PRESENT(
+							bus->chipco.status);
+		case 0x4322:
+			return SSB_CHIPCO_CHST_4322_SPROM_PRESENT(
+							bus->chipco.status);
+		case 0x4325:
+			return SSB_CHIPCO_CHST_4325_SPROM_PRESENT(
+							bus->chipco.status);
+		default:
+			break;
+		}
+
+		if (bus->chipco.dev->id.revision >= 31)
+			return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
+	}
+	return true;
+}
diff --git a/include/linux/ssb/ssb.h b/include/linux/ssb/ssb.h
index 24f9885..3b4da23 100644
--- a/include/linux/ssb/ssb.h
+++ b/include/linux/ssb/ssb.h
@@ -394,6 +394,9 @@ extern int ssb_bus_sdiobus_register(struct ssb_bus *bus,
 
 extern void ssb_bus_unregister(struct ssb_bus *bus);
 
+/* Does the device have an SPROM? */
+extern bool ssb_is_sprom_available(struct ssb_bus *bus);
+
 /* Set a fallback SPROM.
  * See kdoc at the function definition for complete documentation. */
 extern int ssb_arch_set_fallback_sprom(const struct ssb_sprom *sprom);
diff --git a/include/linux/ssb/ssb_driver_chipcommon.h b/include/linux/ssb/ssb_driver_chipcommon.h
index 4e27acf..2cdf249 100644
--- a/include/linux/ssb/ssb_driver_chipcommon.h
+++ b/include/linux/ssb/ssb_driver_chipcommon.h
@@ -53,6 +53,7 @@
 #define  SSB_CHIPCO_CAP_64BIT		0x08000000	/* 64-bit Backplane */
 #define  SSB_CHIPCO_CAP_PMU		0x10000000	/* PMU available (rev >= 20) */
 #define  SSB_CHIPCO_CAP_ECI		0x20000000	/* ECI available (rev >= 20) */
+#define  SSB_CHIPCO_CAP_SPROM		0x40000000	/* SPROM present */
 #define SSB_CHIPCO_CORECTL		0x0008
 #define  SSB_CHIPCO_CORECTL_UARTCLK0	0x00000001	/* Drive UART with internal clock */
 #define	 SSB_CHIPCO_CORECTL_SE		0x00000002	/* sync clk out enable (corerev >= 3) */
@@ -385,6 +386,7 @@
 
 
 /** Chip specific Chip-Status register contents. */
+#define SSB_CHIPCO_CHST_4322_SPROM_EXISTS	0x00000040 /* SPROM present */
 #define SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL	0x00000003
 #define SSB_CHIPCO_CHST_4325_DEFCIS_SEL		0 /* OTP is powered up, use def. CIS, no SPROM */
 #define SSB_CHIPCO_CHST_4325_SPROM_SEL		1 /* OTP is powered up, SPROM is present */
@@ -398,6 +400,18 @@
 #define SSB_CHIPCO_CHST_4325_RCAL_VALUE_SHIFT	4
 #define SSB_CHIPCO_CHST_4325_PMUTOP_2B 		0x00000200 /* 1 for 2b, 0 for to 2a */
 
+/** Macros to determine SPROM presence based on Chip-Status register. */
+#define SSB_CHIPCO_CHST_4312_SPROM_PRESENT(status) \
+	((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_OTP_SEL)
+#define SSB_CHIPCO_CHST_4322_SPROM_PRESENT(status) \
+	(status & SSB_CHIPCO_CHST_4322_SPROM_EXISTS)
+#define SSB_CHIPCO_CHST_4325_SPROM_PRESENT(status) \
+	(((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_DEFCIS_SEL) && \
+	 ((status & SSB_CHIPCO_CHST_4325_SPROM_OTP_SEL) != \
+		SSB_CHIPCO_CHST_4325_OTP_SEL))
+
 
 
 /** Clockcontrol masks and values **/
@@ -564,6 +578,7 @@ struct ssb_chipcommon_pmu {
 struct ssb_chipcommon {
 	struct ssb_device *dev;
 	u32 capabilities;
+	u32 status;
 	/* Fast Powerup Delay constant */
 	u16 fast_pwrup_delay;
 	struct ssb_chipcommon_pmu pmu;
-- 
1.6.4.2

Re: [PATCH V2] ssb: do not read SPROM if it does not exist

[Michael Buesch]

On Wednesday 31 March 2010 20:21:02 Rafał Miłecki wrote:
> Attempting to read registers that don't exist on the SSB bus can cause
> hangs on some boxes.  At least some b43 devices are 'in the wild' that
> don't have SPROMs at all.  When the SSB bus support loads, it attempts
> to read these (non-existant) SPROMs and causes hard hangs on the box --
> no console output, etc.
> 
> This patch adds some intelligence to determine whether or not the SPROM
> is present before attempting to read it.  This avoids those hard hangs
> on those devices with no SPROM attached to their SSB bus.  The
> SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
> will survive to test further patches. :-)
> 
> Signed-off-by: John W. Linville <linville@tuxdriver.com>
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
> Cc: Larry Finger <Larry.Finger@lwfinger.net>
> Cc: Michael Buesch <mb@bu3sch.de>
> ---
> V2: adapt to updated specs, drop some warning-causing braces
> 
> Do I understand correctly this patch can be applied even without fix for
> location of SPROM? AFAIU that is separated issue and we do not support
> SPROM with recently discovered location anyway. However this should fix
> hangs on boards without SPROM, right?
> 
> John: I searched for explaination of Signed-off-by and found info it shows
> people involved in creating patch. As this one is mostly based on yours, I
> have kept your S-o-b line. Is that OK? Is this also OK I added myself, even
> if my involvement is much lower than yours?
> 
> Please do not irritate if I done this incorrectly :)
> 
> So finally: can someone test this, please? John?
> ---
>  drivers/ssb/driver_chipcommon.c           |    2 +
>  drivers/ssb/pci.c                         |    5 ++++
>  drivers/ssb/sprom.c                       |   30 +++++++++++++++++++++++++++++
>  include/linux/ssb/ssb.h                   |    3 ++
>  include/linux/ssb/ssb_driver_chipcommon.h |   15 ++++++++++++++
>  5 files changed, 55 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/ssb/driver_chipcommon.c b/drivers/ssb/driver_chipcommon.c
> index 59c3c0f..59ae76b 100644
> --- a/drivers/ssb/driver_chipcommon.c
> +++ b/drivers/ssb/driver_chipcommon.c
> @@ -233,6 +233,8 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
>  {
>  	if (!cc->dev)
>  		return; /* We don't have a ChipCommon */
> +	if (cc->dev->id.revision >= 11)
> +		cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
>  	ssb_pmu_init(cc);
>  	chipco_powercontrol_init(cc);
>  	ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);
> diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
> index 9e50896..a4b2b99 100644
> --- a/drivers/ssb/pci.c
> +++ b/drivers/ssb/pci.c
> @@ -620,6 +620,11 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
>  	int err = -ENOMEM;
>  	u16 *buf;
>  
> +	if (!ssb_is_sprom_available(bus)) {
> +		ssb_printk(KERN_ERR PFX "No SPROM available!\n");
> +		return -ENODEV;
> +	}
> +
>  	buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
>  	if (!buf)
>  		goto out;
> diff --git a/drivers/ssb/sprom.c b/drivers/ssb/sprom.c
> index d0e6762..fbaa68c 100644
> --- a/drivers/ssb/sprom.c
> +++ b/drivers/ssb/sprom.c
> @@ -175,3 +175,33 @@ const struct ssb_sprom *ssb_get_fallback_sprom(void)
>  {
>  	return fallback_sprom;
>  }
> +
> +bool ssb_is_sprom_available(struct ssb_bus *bus)
> +{
> +	if (bus->bustype == SSB_BUSTYPE_PCI) {
> +		if (bus->chipco.dev->id.revision >= 31)
> +			return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
> +	} else if (bus->bustype == SSB_BUSTYPE_PCMCIA) {

Please note that this whole PCMCIA branch will be dead and never be executed.
We do not access the SPROM directly on PCMCIA. We use the PCMCIA tuples
for fetching the information.

> +		/* status register only exists on chipcomon rev >= 11 */
> +		if (bus->chipco.dev->id.revision < 11)
> +			return true;
> +
> +		switch (bus->chip_id) {
> +		case 0x4312:
> +			return SSB_CHIPCO_CHST_4312_SPROM_PRESENT(
> +							bus->chipco.status);
> +		case 0x4322:
> +			return SSB_CHIPCO_CHST_4322_SPROM_PRESENT(
> +							bus->chipco.status);
> +		case 0x4325:
> +			return SSB_CHIPCO_CHST_4325_SPROM_PRESENT(
> +							bus->chipco.status);
> +		default:
> +			break;
> +		}
> +
> +		if (bus->chipco.dev->id.revision >= 31)
> +			return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
> +	}
> +	return true;
> +}

-- 
Greetings, Michael.

Re: [PATCH V2] ssb: do not read SPROM if it does not exist

[Larry Finger]

On 03/31/2010 01:21 PM, Rafał Miłecki wrote:
> Attempting to read registers that don't exist on the SSB bus can cause
> hangs on some boxes.  At least some b43 devices are 'in the wild' that
> don't have SPROMs at all.  When the SSB bus support loads, it attempts
> to read these (non-existant) SPROMs and causes hard hangs on the box --
> no console output, etc.
> 
> This patch adds some intelligence to determine whether or not the SPROM
> is present before attempting to read it.  This avoids those hard hangs
> on those devices with no SPROM attached to their SSB bus.  The
> SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
> will survive to test further patches. :-)
> 
> Signed-off-by: John W. Linville <linville@tuxdriver.com>
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
> Cc: Larry Finger <Larry.Finger@lwfinger.net>
> Cc: Michael Buesch <mb@bu3sch.de>
> ---
> V2: adapt to updated specs, drop some warning-causing braces
> 
> Do I understand correctly this patch can be applied even without fix for
> location of SPROM? AFAIU that is separated issue and we do not support
> SPROM with recently discovered location anyway. However this should fix
> hangs on boards without SPROM, right?

It is separate from the SPROM location change.

> John: I searched for explaination of Signed-off-by and found info it shows
> people involved in creating patch. As this one is mostly based on yours, I
> have kept your S-o-b line. Is that OK? Is this also OK I added myself, even
> if my involvement is much lower than yours?
> 
> Please do not irritate if I done this incorrectly :)
> 
> So finally: can someone test this, please? John?

The usual way to do this is to include a From: line as the first thing
in the patch. That indicates that the patch is not from the person that
actually submitted it, and it implies a sighed-off-by.

> ---
>  drivers/ssb/driver_chipcommon.c           |    2 +
>  drivers/ssb/pci.c                         |    5 ++++
>  drivers/ssb/sprom.c                       |   30 +++++++++++++++++++++++++++++
>  include/linux/ssb/ssb.h                   |    3 ++
>  include/linux/ssb/ssb_driver_chipcommon.h |   15 ++++++++++++++
>  5 files changed, 55 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/ssb/driver_chipcommon.c b/drivers/ssb/driver_chipcommon.c
> index 59c3c0f..59ae76b 100644
> --- a/drivers/ssb/driver_chipcommon.c
> +++ b/drivers/ssb/driver_chipcommon.c
> @@ -233,6 +233,8 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
>  {
>  	if (!cc->dev)
>  		return; /* We don't have a ChipCommon */
> +	if (cc->dev->id.revision >= 11)
> +		cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
>  	ssb_pmu_init(cc);
>  	chipco_powercontrol_init(cc);
>  	ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);
> diff --git a/drivers/ssb/pci.c b/drivers/ssb/pci.c
> index 9e50896..a4b2b99 100644
> --- a/drivers/ssb/pci.c
> +++ b/drivers/ssb/pci.c
> @@ -620,6 +620,11 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
>  	int err = -ENOMEM;
>  	u16 *buf;
>  
> +	if (!ssb_is_sprom_available(bus)) {
> +		ssb_printk(KERN_ERR PFX "No SPROM available!\n");
> +		return -ENODEV;
> +	}
> +
>  	buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
>  	if (!buf)
>  		goto out;
> diff --git a/drivers/ssb/sprom.c b/drivers/ssb/sprom.c
> index d0e6762..fbaa68c 100644
> --- a/drivers/ssb/sprom.c
> +++ b/drivers/ssb/sprom.c
> @@ -175,3 +175,33 @@ const struct ssb_sprom *ssb_get_fallback_sprom(void)
>  {
>  	return fallback_sprom;
>  }
> +
> +bool ssb_is_sprom_available(struct ssb_bus *bus)
> +{
> +	if (bus->bustype == SSB_BUSTYPE_PCI) {
> +		if (bus->chipco.dev->id.revision >= 31)
> +			return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
> +	} else if (bus->bustype == SSB_BUSTYPE_PCMCIA) {
> +		/* status register only exists on chipcomon rev >= 11 */
> +		if (bus->chipco.dev->id.revision < 11)
> +			return true;
> +

I works as is, but seeing the above if caused me to revise the specs a
little. The test for chip common revision < 11 should be first.

Larry