[PATCH 2/6] ARM: mvebu: start using the CPU reset driver

[Gregory CLEMENT]

On 27/03/2014 14:38, Thomas Petazzoni wrote:
> This commit changes the PMSU driver to no longer map itself the CPU
> reset registers, and instead call into the CPU reset driver to
> deassert the secondary CPUs for SMP booting.
> 
> In order to provide Device Tree backward compatibility, the CPU reset
> driver is extended to not only support its official compatible strings
> "marvell,armada-370-cpu-reset" and "marvell,armada-xp-cpu-reset", but
> to also look at the PMSU compatible string
> "marvell,armada-370-xp-pmsu" to find the CPU reset registers
> address. This allows old Device Tree to work correctly with newer
> kernel versions. Therefore, the CPU reset driver implements the
> following logic:
> 
>  * If one of the normal compatible strings
>    "marvell,armada-<chip>-cpu-reset" is found, then we map its first
>    memory resource as the CPU reset registers.
> 
>  * Otherwise, if none of the normal compatible strings have been
>    found, we look for the "marvell,armada-370-xp-pmsu" compatible
>    string, and we map the second memory as the CPU reset registers.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>

Acked-by: Gregory CLEMENT <gregory.clement at free-electrons.com>


> ---
>  arch/arm/mach-mvebu/cpu-reset.c | 56 ++++++++++++++++++++++++++++-------------
>  arch/arm/mach-mvebu/pmsu.c      | 20 +++++++--------
>  2 files changed, 48 insertions(+), 28 deletions(-)
> 
> diff --git a/arch/arm/mach-mvebu/cpu-reset.c b/arch/arm/mach-mvebu/cpu-reset.c
> index 2819887..e3821b1 100644
> --- a/arch/arm/mach-mvebu/cpu-reset.c
> +++ b/arch/arm/mach-mvebu/cpu-reset.c
> @@ -46,43 +46,63 @@ int mvebu_cpu_reset_deassert(int cpu)
>  	return 0;
>  }
>  
> -static int __init mvebu_cpu_reset_init(void)
> +static int mvebu_cpu_reset_map(struct device_node *np, int res_idx)
>  {
> -	struct device_node *np;
> -	const struct of_device_id *match;
>  	struct resource res;
> -	int ret = 0;
>  
> -	np = of_find_matching_node_and_match(NULL, of_cpu_reset_table,
> -					     &match);
> -	if (!np)
> -		return 0;
> -
> -	if (of_address_to_resource(np, 0, &res)) {
> +	if (of_address_to_resource(np, res_idx, &res)) {
>  		pr_err("unable to get resource\n");
> -		ret = -ENOENT;
> -		goto out;
> +		return -ENOENT;
>  	}
>  
>  	if (!request_mem_region(res.start, resource_size(&res),
>  				np->full_name)) {
>  		pr_err("unable to request region\n");
> -		ret = -EBUSY;
> -		goto out;
> +		return -EBUSY;
>  	}
>  
>  	cpu_reset_base = ioremap(res.start, resource_size(&res));
>  	if (!cpu_reset_base) {
>  		pr_err("unable to map registers\n");
>  		release_mem_region(res.start, resource_size(&res));
> -		ret = -ENOMEM;
> -		goto out;
> +		return -ENOMEM;
>  	}
>  
> -	ncpus = (int) match->data;
> +	return 0;
> +}
>  
> -out:
> +int __init mvebu_cpu_reset_init(void)
> +{
> +	struct device_node *np;
> +	const struct of_device_id *match;
> +	int res_idx;
> +	int ret;
> +
> +	np = of_find_matching_node_and_match(NULL, of_cpu_reset_table,
> +					     &match);
> +	if (np) {
> +		res_idx = 0;
> +		ncpus = (int) match->data;
> +	} else {
> +		/*
> +		 * This code is kept for backward compatibility with
> +		 * old Device Trees.
> +		 */
> +		np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-pmsu");
> +		if (np) {
> +			pr_warn(FW_WARN "deprecated pmsu binding\n");
> +			res_idx = 1;
> +			ncpus = ARMADA_XP_MAX_CPUS;
> +		}
> +	}
> +
> +	/* No reset node found */
> +	if (!np)
> +		return 0;
> +
> +	ret = mvebu_cpu_reset_map(np, res_idx);
>  	of_node_put(np);
> +
>  	return ret;
>  }
>  
> diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c
> index d71ef53..1807639 100644
> --- a/arch/arm/mach-mvebu/pmsu.c
> +++ b/arch/arm/mach-mvebu/pmsu.c
> @@ -21,14 +21,14 @@
>  #include <linux/of_address.h>
>  #include <linux/io.h>
>  #include <linux/smp.h>
> +#include <linux/resource.h>
>  #include <asm/smp_plat.h>
> +#include "common.h"
>  #include "pmsu.h"
>  
>  static void __iomem *pmsu_mp_base;
> -static void __iomem *pmsu_reset_base;
>  
>  #define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu)	((cpu * 0x100) + 0x24)
> -#define PMSU_RESET_CTL_OFFSET(cpu)		(cpu * 0x8)
>  
>  static struct of_device_id of_pmsu_table[] = {
>  	{.compatible = "marvell,armada-370-xp-pmsu"},
> @@ -38,11 +38,11 @@ static struct of_device_id of_pmsu_table[] = {
>  #ifdef CONFIG_SMP
>  int armada_xp_boot_cpu(unsigned int cpu_id, void *boot_addr)
>  {
> -	int reg, hw_cpu;
> +	int hw_cpu, ret;
>  
> -	if (!pmsu_mp_base || !pmsu_reset_base) {
> +	if (!pmsu_mp_base) {
>  		pr_warn("Can't boot CPU. PMSU is uninitialized\n");
> -		return 1;
> +		return -ENODEV;
>  	}
>  
>  	hw_cpu = cpu_logical_map(cpu_id);
> @@ -50,10 +50,11 @@ int armada_xp_boot_cpu(unsigned int cpu_id, void *boot_addr)
>  	writel(virt_to_phys(boot_addr), pmsu_mp_base +
>  			PMSU_BOOT_ADDR_REDIRECT_OFFSET(hw_cpu));
>  
> -	/* Release CPU from reset by clearing reset bit*/
> -	reg = readl(pmsu_reset_base + PMSU_RESET_CTL_OFFSET(hw_cpu));
> -	reg &= (~0x1);
> -	writel(reg, pmsu_reset_base + PMSU_RESET_CTL_OFFSET(hw_cpu));
> +	ret = mvebu_cpu_reset_deassert(hw_cpu);
> +	if (ret) {
> +		pr_warn("unable to boot CPU: %d\n", ret);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
> @@ -67,7 +68,6 @@ static int __init armada_370_xp_pmsu_init(void)
>  	if (np) {
>  		pr_info("Initializing Power Management Service Unit\n");
>  		pmsu_mp_base = of_iomap(np, 0);
> -		pmsu_reset_base = of_iomap(np, 1);
>  		of_node_put(np);
>  	}
>  
> 


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com