diff mbox

arm: ep93xx: use soc bus

Message ID 201306041130.52573.hartleys@visionengravers.com (mailing list archive)
State New, archived
Headers show

Commit Message

Hartley Sweeten June 4, 2013, 6:30 p.m. UTC
Use the soc bus to report the silicon revision and Maverick Key. Both
are not currently exposed to the user. In addition, fill in the SoC
family and machine for completeness.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
---
 arch/arm/mach-ep93xx/Kconfig                 |   1 +
 arch/arm/mach-ep93xx/core.c                  | 106 ++++++++++++++++++++++++++-
 arch/arm/mach-ep93xx/include/mach/platform.h |   3 +-
 3 files changed, 108 insertions(+), 2 deletions(-)

Comments

Ryan Mallon June 4, 2013, 11:03 p.m. UTC | #1
On 05/06/13 04:30, H Hartley Sweeten wrote:
> Use the soc bus to report the silicon revision and Maverick Key. Both
> are not currently exposed to the user. In addition, fill in the SoC
> family and machine for completeness.
> 
> Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
> Cc: Ryan Mallon <rmallon@gmail.com>

Hey Hartley,

Looks mostly good. Couple of comments below.

~Ryan

> ---
>  arch/arm/mach-ep93xx/Kconfig                 |   1 +
>  arch/arm/mach-ep93xx/core.c                  | 106 ++++++++++++++++++++++++++-
>  arch/arm/mach-ep93xx/include/mach/platform.h |   3 +-
>  3 files changed, 108 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-ep93xx/Kconfig b/arch/arm/mach-ep93xx/Kconfig
> index fe3c1fa..91eee1d 100644
> --- a/arch/arm/mach-ep93xx/Kconfig
> +++ b/arch/arm/mach-ep93xx/Kconfig
> @@ -5,6 +5,7 @@ menu "Cirrus EP93xx Implementation Options"
>  config EP93XX_SOC_COMMON
>  	bool
>  	default y
> +	select SOC_BUS
>  	select LEDS_GPIO_REGISTER
>  
>  config CRUNCH
> diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
> index c49ed3d..d6c0c0b 100644
> --- a/arch/arm/mach-ep93xx/core.c
> +++ b/arch/arm/mach-ep93xx/core.c
> @@ -21,6 +21,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/interrupt.h>
>  #include <linux/dma-mapping.h>
> +#include <linux/sys_soc.h>
>  #include <linux/timex.h>
>  #include <linux/irq.h>
>  #include <linux/io.h>
> @@ -42,6 +43,7 @@
>  #include <linux/platform_data/spi-ep93xx.h>
>  #include <mach/gpio-ep93xx.h>
>  
> +#include <asm/mach/arch.h>
>  #include <asm/mach/map.h>
>  #include <asm/mach/time.h>
>  
> @@ -895,8 +897,106 @@ void ep93xx_ide_release_gpio(struct platform_device *pdev)
>  }
>  EXPORT_SYMBOL(ep93xx_ide_release_gpio);
>  
> -void __init ep93xx_init_devices(void)
> +/*************************************************************************
> + * EP93xx Security peripheral
> + *************************************************************************/
> +
> +/*
> + * The Maverick Key is 256 bits of micro fuses blown at the factory during
> + * manufacturing to uniquely identify a part.
> + *
> + * See: http://arm.cirrus.com/forum/viewtopic.php?t=486&highlight=maverick+key
> + */
> +#define EP93XX_SECURITY_REG(x)		(EP93XX_SECURITY_BASE + (x))
> +#define EP93XX_SECURITY_UNIQID		EP93XX_SECURITY_REG(0x2440)
> +#define EP93XX_SECURITY_UNIQCHK		EP93XX_SECURITY_REG(0x2450)
> +#define EP93XX_SECURITY_SECID1		EP93XX_SECURITY_REG(0x2500)
> +#define EP93XX_SECURITY_SECCHK1		EP93XX_SECURITY_REG(0x2520)
> +#define EP93XX_SECURITY_SECID2		EP93XX_SECURITY_REG(0x2504)
> +#define EP93XX_SECURITY_SECCHK2		EP93XX_SECURITY_REG(0x2524)
> +#define EP93XX_SECURITY_FUSEFLG		EP93XX_SECURITY_REG(0x2410)
> +#define EP93XX_SECURITY_UNIQID2		EP93XX_SECURITY_REG(0x2700)
> +#define EP93XX_SECURITY_UNIQID3		EP93XX_SECURITY_REG(0x2704)
> +#define EP93XX_SECURITY_UNIQID4		EP93XX_SECURITY_REG(0x2708)
> +#define EP93XX_SECURITY_UNIQID5		EP93XX_SECURITY_REG(0x270c)
> +#define EP93XX_SECURITY_SECFLG		EP93XX_SECURITY_REG(0x2400)
> +#define EP93XX_SECURITY_UNIQVAL		EP93XX_SECURITY_REG(0x2460)

You are only using about half of these defines. Are you expecting to use
some more of them in the future, or could we just remove the unused ones?

> +
> +static const char __init *ep93xx_get_soc_id(void)
> +{
> +	unsigned int id, id2, id3, id4, id5;
> +
> +	if (__raw_readl(EP93XX_SECURITY_UNIQVAL) != 1)
> +		return kasprintf(GFP_KERNEL, "bad Hamming code");
> +
> +	id = __raw_readl(EP93XX_SECURITY_UNIQID);
> +	id2 = __raw_readl(EP93XX_SECURITY_UNIQID2);
> +	id3 = __raw_readl(EP93XX_SECURITY_UNIQID3);
> +	id4 = __raw_readl(EP93XX_SECURITY_UNIQID4);
> +	id5 = __raw_readl(EP93XX_SECURITY_UNIQID5);
> +
> +	if (id != id2)
> +		return kasprintf(GFP_KERNEL, "invalid");
> +
> +	return kasprintf(GFP_KERNEL,"%08x%08x%08x%08x",
> +			 id2, id3, id4, id5);
> +}

You don't need to use the allocator functions here:

static char soc_id[33];

static const char __init *ep93xx_get_soc_id(void)
{
	if (...)
		return "bad Hamming code";
	...
	
	snprintf(soc_id, sizeof(soc_id), ...);
	return soc_id;
}

> +
> +static const char __init *ep93xx_get_soc_rev(void)
> +{
> +	int rev = ep93xx_chip_revision();
> +
> +	switch (rev) {
> +	case EP93XX_CHIP_REV_D0:
> +		return "D0";
> +	case EP93XX_CHIP_REV_D1:
> +		return "D1";
> +	case EP93XX_CHIP_REV_E0:
> +		return "E0";
> +	case EP93XX_CHIP_REV_E1:
> +		return "E1";
> +	case EP93XX_CHIP_REV_E2:
> +		return "E2";
> +	default:
> +		return "unknown";
> +	}
> +}
> +
> +static const char __init *ep93xx_get_machine_name(void)
> +{
> +	return kasprintf(GFP_KERNEL,"%s", machine_desc->name);
> +}
> +
> +static struct device __init *ep93xx_init_soc(void)
> +{
> +	struct soc_device_attribute *soc_dev_attr;
> +	struct soc_device *soc_dev;
> +
> +	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
> +	if (!soc_dev_attr)
> +		return NULL;
> +
> +	soc_dev_attr->machine = ep93xx_get_machine_name();
> +	soc_dev_attr->family = "Cirrus EP93xx";
> +	soc_dev_attr->revision = ep93xx_get_soc_rev();
> +	soc_dev_attr->soc_id = ep93xx_get_soc_id();
> +
> +	soc_dev = soc_device_register(soc_dev_attr);
> +	if (IS_ERR(soc_dev)) {
> +		kfree(soc_dev_attr->soc_id);
> +		kfree(soc_dev_attr->revision);

Revision wasn't allocated with kmalloc.

> +		kfree(soc_dev_attr->machine);
> +		kfree(soc_dev_attr);
> +		return NULL;
> +	}
> +
> +	return soc_device_to_device(soc_dev);
> +}
> +
> +struct device __init *ep93xx_init_devices(void)
>  {
> +	struct device *parent;
> +
>  	/* Disallow access to MaverickCrunch initially */
>  	ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_CPENA);
>  
> @@ -907,6 +1007,8 @@ void __init ep93xx_init_devices(void)
>  			       EP93XX_SYSCON_DEVCFG_GONIDE |
>  			       EP93XX_SYSCON_DEVCFG_HONIDE);
>  
> +	parent = ep93xx_init_soc();
> +
>  	/* Get the GPIO working early, other devices need it */
>  	platform_device_register(&ep93xx_gpio_device);
>  
> @@ -919,6 +1021,8 @@ void __init ep93xx_init_devices(void)
>  	platform_device_register(&ep93xx_wdt_device);
>  
>  	gpio_led_register_device(-1, &ep93xx_led_data);
> +
> +	return parent;

Nothing appears to use or check this return value?

>  }
>  
>  void ep93xx_restart(char mode, const char *cmd)
> diff --git a/arch/arm/mach-ep93xx/include/mach/platform.h b/arch/arm/mach-ep93xx/include/mach/platform.h
> index a14e1b3..067cf1f 100644
> --- a/arch/arm/mach-ep93xx/include/mach/platform.h
> +++ b/arch/arm/mach-ep93xx/include/mach/platform.h
> @@ -4,6 +4,7 @@
>  
>  #ifndef __ASSEMBLY__
>  
> +struct device;
>  struct i2c_gpio_platform_data;
>  struct i2c_board_info;
>  struct spi_board_info;
> @@ -52,7 +53,7 @@ void ep93xx_register_ide(void);
>  int ep93xx_ide_acquire_gpio(struct platform_device *pdev);
>  void ep93xx_ide_release_gpio(struct platform_device *pdev);
>  
> -void ep93xx_init_devices(void);
> +struct device *ep93xx_init_devices(void);
>  extern void ep93xx_timer_init(void);
>  
>  void ep93xx_restart(char, const char *);
>
Hartley Sweeten June 5, 2013, 1:22 a.m. UTC | #2
On Tuesday, June 04, 2013 4:03 PM, Ryan Mallon wrote:
> On 05/06/13 04:30, H Hartley Sweeten wrote:
>> Use the soc bus to report the silicon revision and Maverick Key. Both
>> are not currently exposed to the user. In addition, fill in the SoC
>> family and machine for completeness.
>> 
>> Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
>> Cc: Ryan Mallon <rmallon@gmail.com>
>
> Hey Hartley,
>
> Looks mostly good. Couple of comments below.
>
> ~Ryan
>
>> ---
>>  arch/arm/mach-ep93xx/Kconfig                 |   1 +
>>  arch/arm/mach-ep93xx/core.c                  | 106 ++++++++++++++++++++++++++-
>>  arch/arm/mach-ep93xx/include/mach/platform.h |   3 +-
>>  3 files changed, 108 insertions(+), 2 deletions(-)
>> 
>> diff --git a/arch/arm/mach-ep93xx/Kconfig b/arch/arm/mach-ep93xx/Kconfig
>> index fe3c1fa..91eee1d 100644
>> --- a/arch/arm/mach-ep93xx/Kconfig
>> +++ b/arch/arm/mach-ep93xx/Kconfig
>> @@ -5,6 +5,7 @@ menu "Cirrus EP93xx Implementation Options"
>>  config EP93XX_SOC_COMMON
>>  	bool
>>  	default y
>> +	select SOC_BUS
>>  	select LEDS_GPIO_REGISTER
>>  
>>  config CRUNCH
>> diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
>> index c49ed3d..d6c0c0b 100644
>> --- a/arch/arm/mach-ep93xx/core.c
>> +++ b/arch/arm/mach-ep93xx/core.c
>> @@ -21,6 +21,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/dma-mapping.h>
>> +#include <linux/sys_soc.h>
>>  #include <linux/timex.h>
>>  #include <linux/irq.h>
>>  #include <linux/io.h>
>> @@ -42,6 +43,7 @@
>>  #include <linux/platform_data/spi-ep93xx.h>
>>  #include <mach/gpio-ep93xx.h>
>>  
>> +#include <asm/mach/arch.h>
>>  #include <asm/mach/map.h>
>>  #include <asm/mach/time.h>
>>  
>> @@ -895,8 +897,106 @@ void ep93xx_ide_release_gpio(struct platform_device *pdev)
>>  }
>>  EXPORT_SYMBOL(ep93xx_ide_release_gpio);
>>  
>> -void __init ep93xx_init_devices(void)
>> +/*************************************************************************
>> + * EP93xx Security peripheral
>> + *************************************************************************/
>> +
>> +/*
>> + * The Maverick Key is 256 bits of micro fuses blown at the factory during
>> + * manufacturing to uniquely identify a part.
>> + *
>> + * See: http://arm.cirrus.com/forum/viewtopic.php?t=486&highlight=maverick+key
>> + */
>> +#define EP93XX_SECURITY_REG(x)		(EP93XX_SECURITY_BASE + (x))
>> +#define EP93XX_SECURITY_UNIQID		EP93XX_SECURITY_REG(0x2440)
>> +#define EP93XX_SECURITY_UNIQCHK		EP93XX_SECURITY_REG(0x2450)
>> +#define EP93XX_SECURITY_SECID1		EP93XX_SECURITY_REG(0x2500)
>> +#define EP93XX_SECURITY_SECCHK1		EP93XX_SECURITY_REG(0x2520)
>> +#define EP93XX_SECURITY_SECID2		EP93XX_SECURITY_REG(0x2504)
>> +#define EP93XX_SECURITY_SECCHK2		EP93XX_SECURITY_REG(0x2524)
>> +#define EP93XX_SECURITY_FUSEFLG		EP93XX_SECURITY_REG(0x2410)
>> +#define EP93XX_SECURITY_UNIQID2		EP93XX_SECURITY_REG(0x2700)
>> +#define EP93XX_SECURITY_UNIQID3		EP93XX_SECURITY_REG(0x2704)
>> +#define EP93XX_SECURITY_UNIQID4		EP93XX_SECURITY_REG(0x2708)
>> +#define EP93XX_SECURITY_UNIQID5		EP93XX_SECURITY_REG(0x270c)
>> +#define EP93XX_SECURITY_SECFLG		EP93XX_SECURITY_REG(0x2400)
>> +#define EP93XX_SECURITY_UNIQVAL		EP93XX_SECURITY_REG(0x2460)
>
> You are only using about half of these defines. Are you expecting to use
> some more of them in the future, or could we just remove the unused ones?

The Maverick Key is not documented in the EP93xx Users Guide.
Chapter 29 - Security, just says to contact Cirrus Logic for additional information.

I would like to keep the defines here for documentation.

>> +
>> +static const char __init *ep93xx_get_soc_id(void)
>> +{
>> +	unsigned int id, id2, id3, id4, id5;
>> +
>> +	if (__raw_readl(EP93XX_SECURITY_UNIQVAL) != 1)
>> +		return kasprintf(GFP_KERNEL, "bad Hamming code");
>> +
>> +	id = __raw_readl(EP93XX_SECURITY_UNIQID);
>> +	id2 = __raw_readl(EP93XX_SECURITY_UNIQID2);
>> +	id3 = __raw_readl(EP93XX_SECURITY_UNIQID3);
>> +	id4 = __raw_readl(EP93XX_SECURITY_UNIQID4);
>> +	id5 = __raw_readl(EP93XX_SECURITY_UNIQID5);
>> +
>> +	if (id != id2)
>> +		return kasprintf(GFP_KERNEL, "invalid");
>> +
>> +	return kasprintf(GFP_KERNEL,"%08x%08x%08x%08x",
>> +			 id2, id3, id4, id5);
>> +}
>
> You don't need to use the allocator functions here:
>
> static char soc_id[33];
>
> static const char __init *ep93xx_get_soc_id(void)
> {
>	if (...)
>		return "bad Hamming code";
>	...
>	
>	snprintf(soc_id, sizeof(soc_id), ...);
>	return soc_id;
> }

I'm not sure which is cleaner. Only one of the allocator functions actually
gets called.

>> +
>> +static const char __init *ep93xx_get_soc_rev(void)
>> +{
>> +	int rev = ep93xx_chip_revision();
>> +
>> +	switch (rev) {
>> +	case EP93XX_CHIP_REV_D0:
>> +		return "D0";
>> +	case EP93XX_CHIP_REV_D1:
>> +		return "D1";
>> +	case EP93XX_CHIP_REV_E0:
>> +		return "E0";
>> +	case EP93XX_CHIP_REV_E1:
>> +		return "E1";
>> +	case EP93XX_CHIP_REV_E2:
>> +		return "E2";
>> +	default:
>> +		return "unknown";
>> +	}
>> +}
>> +
>> +static const char __init *ep93xx_get_machine_name(void)
>> +{
>> +	return kasprintf(GFP_KERNEL,"%s", machine_desc->name);
>> +}
>> +
>> +static struct device __init *ep93xx_init_soc(void)
>> +{
>> +	struct soc_device_attribute *soc_dev_attr;
>> +	struct soc_device *soc_dev;
>> +
>> +	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
>> +	if (!soc_dev_attr)
>> +		return NULL;
>> +
>> +	soc_dev_attr->machine = ep93xx_get_machine_name();
>> +	soc_dev_attr->family = "Cirrus EP93xx";
>> +	soc_dev_attr->revision = ep93xx_get_soc_rev();
>> +	soc_dev_attr->soc_id = ep93xx_get_soc_id();
>> +
>> +	soc_dev = soc_device_register(soc_dev_attr);
>> +	if (IS_ERR(soc_dev)) {
>> +		kfree(soc_dev_attr->soc_id);
>> +		kfree(soc_dev_attr->revision);
>
> Revision wasn't allocated with kmalloc.

Doh...

>> +		kfree(soc_dev_attr->machine);
>> +		kfree(soc_dev_attr);
>> +		return NULL;
>> +	}
>> +
>> +	return soc_device_to_device(soc_dev);
>> +}
>> +
>> +struct device __init *ep93xx_init_devices(void)
>>  {
>> +	struct device *parent;
>> +
>>  	/* Disallow access to MaverickCrunch initially */
>>  	ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_CPENA);
>>  
>> @@ -907,6 +1007,8 @@ void __init ep93xx_init_devices(void)
>>  			       EP93XX_SYSCON_DEVCFG_GONIDE |
>>  			       EP93XX_SYSCON_DEVCFG_HONIDE);
>>  
>> +	parent = ep93xx_init_soc();
>> +
>>  	/* Get the GPIO working early, other devices need it */
>>  	platform_device_register(&ep93xx_gpio_device);
>>  
>> @@ -919,6 +1021,8 @@ void __init ep93xx_init_devices(void)
>>  	platform_device_register(&ep93xx_wdt_device);
>>  
>>  	gpio_led_register_device(-1, &ep93xx_led_data);
>> +
>> +	return parent;
>
> Nothing appears to use or check this return value?

Not yet. :-)

The callers can use the return value to add additional board specific
information to the soc bus. For instance the ts72xx has the FPGA
revision and some additional information that might be useful.

I'll wait to see if there are any additional comments before posting
an updated patch.

Regards,
Hartley
diff mbox

Patch

diff --git a/arch/arm/mach-ep93xx/Kconfig b/arch/arm/mach-ep93xx/Kconfig
index fe3c1fa..91eee1d 100644
--- a/arch/arm/mach-ep93xx/Kconfig
+++ b/arch/arm/mach-ep93xx/Kconfig
@@ -5,6 +5,7 @@  menu "Cirrus EP93xx Implementation Options"
 config EP93XX_SOC_COMMON
 	bool
 	default y
+	select SOC_BUS
 	select LEDS_GPIO_REGISTER
 
 config CRUNCH
diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
index c49ed3d..d6c0c0b 100644
--- a/arch/arm/mach-ep93xx/core.c
+++ b/arch/arm/mach-ep93xx/core.c
@@ -21,6 +21,7 @@ 
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
+#include <linux/sys_soc.h>
 #include <linux/timex.h>
 #include <linux/irq.h>
 #include <linux/io.h>
@@ -42,6 +43,7 @@ 
 #include <linux/platform_data/spi-ep93xx.h>
 #include <mach/gpio-ep93xx.h>
 
+#include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 #include <asm/mach/time.h>
 
@@ -895,8 +897,106 @@  void ep93xx_ide_release_gpio(struct platform_device *pdev)
 }
 EXPORT_SYMBOL(ep93xx_ide_release_gpio);
 
-void __init ep93xx_init_devices(void)
+/*************************************************************************
+ * EP93xx Security peripheral
+ *************************************************************************/
+
+/*
+ * The Maverick Key is 256 bits of micro fuses blown at the factory during
+ * manufacturing to uniquely identify a part.
+ *
+ * See: http://arm.cirrus.com/forum/viewtopic.php?t=486&highlight=maverick+key
+ */
+#define EP93XX_SECURITY_REG(x)		(EP93XX_SECURITY_BASE + (x))
+#define EP93XX_SECURITY_UNIQID		EP93XX_SECURITY_REG(0x2440)
+#define EP93XX_SECURITY_UNIQCHK		EP93XX_SECURITY_REG(0x2450)
+#define EP93XX_SECURITY_SECID1		EP93XX_SECURITY_REG(0x2500)
+#define EP93XX_SECURITY_SECCHK1		EP93XX_SECURITY_REG(0x2520)
+#define EP93XX_SECURITY_SECID2		EP93XX_SECURITY_REG(0x2504)
+#define EP93XX_SECURITY_SECCHK2		EP93XX_SECURITY_REG(0x2524)
+#define EP93XX_SECURITY_FUSEFLG		EP93XX_SECURITY_REG(0x2410)
+#define EP93XX_SECURITY_UNIQID2		EP93XX_SECURITY_REG(0x2700)
+#define EP93XX_SECURITY_UNIQID3		EP93XX_SECURITY_REG(0x2704)
+#define EP93XX_SECURITY_UNIQID4		EP93XX_SECURITY_REG(0x2708)
+#define EP93XX_SECURITY_UNIQID5		EP93XX_SECURITY_REG(0x270c)
+#define EP93XX_SECURITY_SECFLG		EP93XX_SECURITY_REG(0x2400)
+#define EP93XX_SECURITY_UNIQVAL		EP93XX_SECURITY_REG(0x2460)
+
+static const char __init *ep93xx_get_soc_id(void)
+{
+	unsigned int id, id2, id3, id4, id5;
+
+	if (__raw_readl(EP93XX_SECURITY_UNIQVAL) != 1)
+		return kasprintf(GFP_KERNEL, "bad Hamming code");
+
+	id = __raw_readl(EP93XX_SECURITY_UNIQID);
+	id2 = __raw_readl(EP93XX_SECURITY_UNIQID2);
+	id3 = __raw_readl(EP93XX_SECURITY_UNIQID3);
+	id4 = __raw_readl(EP93XX_SECURITY_UNIQID4);
+	id5 = __raw_readl(EP93XX_SECURITY_UNIQID5);
+
+	if (id != id2)
+		return kasprintf(GFP_KERNEL, "invalid");
+
+	return kasprintf(GFP_KERNEL,"%08x%08x%08x%08x",
+			 id2, id3, id4, id5);
+}
+
+static const char __init *ep93xx_get_soc_rev(void)
+{
+	int rev = ep93xx_chip_revision();
+
+	switch (rev) {
+	case EP93XX_CHIP_REV_D0:
+		return "D0";
+	case EP93XX_CHIP_REV_D1:
+		return "D1";
+	case EP93XX_CHIP_REV_E0:
+		return "E0";
+	case EP93XX_CHIP_REV_E1:
+		return "E1";
+	case EP93XX_CHIP_REV_E2:
+		return "E2";
+	default:
+		return "unknown";
+	}
+}
+
+static const char __init *ep93xx_get_machine_name(void)
+{
+	return kasprintf(GFP_KERNEL,"%s", machine_desc->name);
+}
+
+static struct device __init *ep93xx_init_soc(void)
+{
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return NULL;
+
+	soc_dev_attr->machine = ep93xx_get_machine_name();
+	soc_dev_attr->family = "Cirrus EP93xx";
+	soc_dev_attr->revision = ep93xx_get_soc_rev();
+	soc_dev_attr->soc_id = ep93xx_get_soc_id();
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr->revision);
+		kfree(soc_dev_attr->machine);
+		kfree(soc_dev_attr);
+		return NULL;
+	}
+
+	return soc_device_to_device(soc_dev);
+}
+
+struct device __init *ep93xx_init_devices(void)
 {
+	struct device *parent;
+
 	/* Disallow access to MaverickCrunch initially */
 	ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_CPENA);
 
@@ -907,6 +1007,8 @@  void __init ep93xx_init_devices(void)
 			       EP93XX_SYSCON_DEVCFG_GONIDE |
 			       EP93XX_SYSCON_DEVCFG_HONIDE);
 
+	parent = ep93xx_init_soc();
+
 	/* Get the GPIO working early, other devices need it */
 	platform_device_register(&ep93xx_gpio_device);
 
@@ -919,6 +1021,8 @@  void __init ep93xx_init_devices(void)
 	platform_device_register(&ep93xx_wdt_device);
 
 	gpio_led_register_device(-1, &ep93xx_led_data);
+
+	return parent;
 }
 
 void ep93xx_restart(char mode, const char *cmd)
diff --git a/arch/arm/mach-ep93xx/include/mach/platform.h b/arch/arm/mach-ep93xx/include/mach/platform.h
index a14e1b3..067cf1f 100644
--- a/arch/arm/mach-ep93xx/include/mach/platform.h
+++ b/arch/arm/mach-ep93xx/include/mach/platform.h
@@ -4,6 +4,7 @@ 
 
 #ifndef __ASSEMBLY__
 
+struct device;
 struct i2c_gpio_platform_data;
 struct i2c_board_info;
 struct spi_board_info;
@@ -52,7 +53,7 @@  void ep93xx_register_ide(void);
 int ep93xx_ide_acquire_gpio(struct platform_device *pdev);
 void ep93xx_ide_release_gpio(struct platform_device *pdev);
 
-void ep93xx_init_devices(void);
+struct device *ep93xx_init_devices(void);
 extern void ep93xx_timer_init(void);
 
 void ep93xx_restart(char, const char *);