Re: [PATCH 20/22] ARM: sun8i: Add SMP support for the Allwinner A23

Maxime Ripard
2014-05-25T19:43:31Z

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On Fri, May 23, 2014 at 03:51:23PM +0800, Chen-Yu Tsai wrote:
> The A23 is a dual Cortex-A7. Add the logic to use the IPs used to
> control the CPU configuration and the CPU power so that we can
> bring up secondary CPUs at boot.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> arch/arm/mach-sunxi/platsmp.c | 69 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/arch/arm/mach-sunxi/platsmp.c b/arch/arm/mach-sunxi/platsmp.c
> index c53077b..688faaf 100644
> --- a/arch/arm/mach-sunxi/platsmp.c
> +++ b/arch/arm/mach-sunxi/platsmp.c
> @@ -121,3 +121,72 @@ struct smp_operations sun6i_smp_ops __initdata = {
> .smp_boot_secondary = sun6i_smp_boot_secondary,
> };
> CPU_METHOD_OF_DECLARE(sun6i_smp, "allwinner,sun6i-a31", &sun6i_smp_ops);
> +
> +static void __init sun8i_smp_prepare_cpus(unsigned int max_cpus)
> +{
> + struct device_node *node;
> +
> + node = of_find_compatible_node(NULL, NULL, "allwinner,sun8i-a23-prcm");
> + if (!node) {
> + pr_err("Missing A23 PRCM node in the device tree\n");
> + return;
> + }
> +
> + prcm_membase = of_iomap(node, 0);
> + if (!prcm_membase) {
> + pr_err("Couldn't map A23 PRCM registers\n");
> + return;
> + }
> +
> + node = of_find_compatible_node(NULL, NULL,
> + "allwinner,sun8i-a23-cpuconfig");
> + if (!node) {
> + pr_err("Missing A23 CPU config node in the device tree\n");
> + return;
> + }
> +
> + cpucfg_membase = of_iomap(node, 0);
> + if (!cpucfg_membase)
> + pr_err("Couldn't map A23 CPU config registers\n");
> +
> +}
> +
> +static int sun8i_smp_boot_secondary(unsigned int cpu,
> + struct task_struct *idle)
> +{
> + u32 reg;
> +
> + if (!(prcm_membase && cpucfg_membase))
> + return -EFAULT;
> +
> + spin_lock(&cpu_lock);
> +
> + /* Set CPU boot address */
> + writel(virt_to_phys(secondary_startup),
> + cpucfg_membase + CPUCFG_PRIVATE0_REG);
> +
> + /* Assert the CPU core in reset */
> + writel(0, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
> +
> + /* Assert the L1 cache in reset */
> + reg = readl(cpucfg_membase + CPUCFG_GEN_CTRL_REG);
> + writel(reg & ~BIT(cpu), cpucfg_membase + CPUCFG_GEN_CTRL_REG);
> +
> + /* Clear CPU power-off gating */
> + reg = readl(prcm_membase + PRCM_CPU_PWROFF_REG);
> + writel(reg & ~BIT(cpu), prcm_membase + PRCM_CPU_PWROFF_REG);
> + mdelay(1);
> +
> + /* Deassert the CPU core reset */
> + writel(3, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
> +
> + spin_unlock(&cpu_lock);
> +
> + return 0;
> +}
> +
> +struct smp_operations sun8i_smp_ops __initdata = {
> + .smp_prepare_cpus = sun8i_smp_prepare_cpus,
> + .smp_boot_secondary = sun8i_smp_boot_secondary,
> +};
> +CPU_METHOD_OF_DECLARE(sun8i_smp, "allwinner,sun8i-a23", &sun8i_smp_ops);

You forgot to document the new enable-method.

Also, is there any plan to hae a working u-boot? I'd much prefer to
use PSCI if possible.

Maxime

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

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