[PATCH 1/3] ARM: at91: use chipid device for soc detection

[alexandre.belloni@free-electrons.com (Alexandre Belloni)]

On 18/03/2016 at 08:21:19 +0100, Ludovic Desroches wrote :
> So far, the CIDR and EXID registers were in the DBGU interface. This device
> has disappeared with the SAMA5D2 family. These registers are exposed
> through a new device called chipid.
> 
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> [nicolas.ferre at atmel.com: remove useless warnings]
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

> ---
>  .../devicetree/bindings/arm/atmel-at91.txt         |  4 ++
>  arch/arm/mach-at91/soc.c                           | 81 +++++++++++++++++-----
>  2 files changed, 67 insertions(+), 18 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt
> index 7fd64ec..0b1fcbf 100644
> --- a/Documentation/devicetree/bindings/arm/atmel-at91.txt
> +++ b/Documentation/devicetree/bindings/arm/atmel-at91.txt
> @@ -41,6 +41,10 @@ compatible: must be one of:
>         - "atmel,sama5d43"
>         - "atmel,sama5d44"
>  
> +Chipid required properties:
> +- compatible: Should be "atmel,sama5d2-chipid"
> +- reg : Should contain registers location and length
> +
>  PIT Timer required properties:
>  - compatible: Should be "atmel,at91sam9260-pit"
>  - reg: Should contain registers location and length
> diff --git a/arch/arm/mach-at91/soc.c b/arch/arm/mach-at91/soc.c
> index 54343ff..034d563 100644
> --- a/arch/arm/mach-at91/soc.c
> +++ b/arch/arm/mach-at91/soc.c
> @@ -22,48 +22,93 @@
>  #include "soc.h"
>  
>  #define AT91_DBGU_CIDR			0x40
> -#define AT91_DBGU_CIDR_VERSION(x)	((x) & 0x1f)
> -#define AT91_DBGU_CIDR_EXT		BIT(31)
> -#define AT91_DBGU_CIDR_MATCH_MASK	0x7fffffe0
>  #define AT91_DBGU_EXID			0x44
> +#define AT91_CHIPID_CIDR		0x00
> +#define AT91_CHIPID_EXID		0x04
> +#define AT91_CIDR_VERSION(x)		((x) & 0x1f)
> +#define AT91_CIDR_EXT			BIT(31)
> +#define AT91_CIDR_MATCH_MASK		0x7fffffe0
>  
> -struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
> +int __init at91_get_cidr_exid_from_dbgu(u32 *cidr, u32 *exid)
>  {
> -	struct soc_device_attribute *soc_dev_attr;
> -	const struct at91_soc *soc;
> -	struct soc_device *soc_dev;
>  	struct device_node *np;
>  	void __iomem *regs;
> -	u32 cidr, exid;
>  
>  	np = of_find_compatible_node(NULL, NULL, "atmel,at91rm9200-dbgu");
>  	if (!np)
>  		np = of_find_compatible_node(NULL, NULL,
>  					     "atmel,at91sam9260-dbgu");
> +	if (!np)
> +		return -ENODEV;
>  
> -	if (!np) {
> -		pr_warn("Could not find DBGU node");
> -		return NULL;
> +	regs = of_iomap(np, 0);
> +	of_node_put(np);
> +
> +	if (!regs) {
> +		pr_warn("Could not map DBGU iomem range");
> +		return -ENXIO;
>  	}
>  
> +	*cidr = readl(regs + AT91_DBGU_CIDR);
> +	*exid = readl(regs + AT91_DBGU_EXID);
> +
> +	iounmap(regs);
> +
> +	return 0;
> +}
> +
> +int __init at91_get_cidr_exid_from_chipid(u32 *cidr, u32 *exid)
> +{
> +	struct device_node *np;
> +	void __iomem *regs;
> +
> +	np = of_find_compatible_node(NULL, NULL, "atmel,sama5d2-chipid");
> +	if (!np)
> +		return -ENODEV;
> +
>  	regs = of_iomap(np, 0);
>  	of_node_put(np);
>  
>  	if (!regs) {
>  		pr_warn("Could not map DBGU iomem range");
> -		return NULL;
> +		return -ENXIO;
>  	}
>  
> -	cidr = readl(regs + AT91_DBGU_CIDR);
> -	exid = readl(regs + AT91_DBGU_EXID);
> +	*cidr = readl(regs + AT91_CHIPID_CIDR);
> +	*exid = readl(regs + AT91_CHIPID_EXID);
>  
>  	iounmap(regs);
>  
> +	return 0;
> +}
> +
> +struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
> +{
> +	struct soc_device_attribute *soc_dev_attr;
> +	const struct at91_soc *soc;
> +	struct soc_device *soc_dev;
> +	u32 cidr, exid;
> +	int ret;
> +
> +	/*
> +	 * With SAMA5D2 and later SoCs, CIDR and EXID registers are no more
> +	 * in the dbgu device but in the chipid device whose purpose is only
> +	 * to expose these two registers.
> +	 */
> +	ret = at91_get_cidr_exid_from_dbgu(&cidr, &exid);
> +	if (ret)
> +		ret = at91_get_cidr_exid_from_chipid(&cidr, &exid);
> +	if (ret) {
> +		if (ret == -ENODEV)
> +			pr_warn("Could not find identification node");
> +		return NULL;
> +	}
> +
>  	for (soc = socs; soc->name; soc++) {
> -		if (soc->cidr_match != (cidr & AT91_DBGU_CIDR_MATCH_MASK))
> +		if (soc->cidr_match != (cidr & AT91_CIDR_MATCH_MASK))
>  			continue;
>  
> -		if (!(cidr & AT91_DBGU_CIDR_EXT) || soc->exid_match == exid)
> +		if (!(cidr & AT91_CIDR_EXT) || soc->exid_match == exid)
>  			break;
>  	}
>  
> @@ -79,7 +124,7 @@ struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
>  	soc_dev_attr->family = soc->family;
>  	soc_dev_attr->soc_id = soc->name;
>  	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X",
> -					   AT91_DBGU_CIDR_VERSION(cidr));
> +					   AT91_CIDR_VERSION(cidr));
>  	soc_dev = soc_device_register(soc_dev_attr);
>  	if (IS_ERR(soc_dev)) {
>  		kfree(soc_dev_attr->revision);
> @@ -91,7 +136,7 @@ struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
>  	if (soc->family)
>  		pr_info("Detected SoC family: %s\n", soc->family);
>  	pr_info("Detected SoC: %s, revision %X\n", soc->name,
> -		AT91_DBGU_CIDR_VERSION(cidr));
> +		AT91_CIDR_VERSION(cidr));
>  
>  	return soc_dev;
>  }
> -- 
> 2.5.0
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com