[PATCH] ARM: sunxi: Fix CPU powerdown on A83T

[PATCH] ARM: sunxi: Fix CPU powerdown on A83T

[Ondrej Jirman]

PRCM_PWROFF_GATING_REG has CPU0 at bit 4 on A83T. So without this
patch, instead of gating the CPU0, the whole cluster was power gated,
when shutting down first CPU in the cluster.

Fixes: 6961275e72a8c1 ("ARM: sun8i: smp: Add support for A83T")
Signed-off-by: Ondrej Jirman <megous@megous.com>
Cc: stable@vger.kernel.org
---
 arch/arm/mach-sunxi/mc_smp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-sunxi/mc_smp.c b/arch/arm/mach-sunxi/mc_smp.c
index 239084cf8192..26cbce135338 100644
--- a/arch/arm/mach-sunxi/mc_smp.c
+++ b/arch/arm/mach-sunxi/mc_smp.c
@@ -481,14 +481,18 @@ static void sunxi_mc_smp_cpu_die(unsigned int l_cpu)
 static int sunxi_cpu_powerdown(unsigned int cpu, unsigned int cluster)
 {
 	u32 reg;
+	int gating_bit = cpu;
 
 	pr_debug("%s: cluster %u cpu %u\n", __func__, cluster, cpu);
 	if (cpu >= SUNXI_CPUS_PER_CLUSTER || cluster >= SUNXI_NR_CLUSTERS)
 		return -EINVAL;
 
+	if (is_a83t && cpu == 0)
+		gating_bit = 4;
+
 	/* gate processor power */
 	reg = readl(prcm_base + PRCM_PWROFF_GATING_REG(cluster));
-	reg |= PRCM_PWROFF_GATING_REG_CORE(cpu);
+	reg |= PRCM_PWROFF_GATING_REG_CORE(gating_bit);
 	writel(reg, prcm_base + PRCM_PWROFF_GATING_REG(cluster));
 	udelay(20);
 
-- 
2.23.0

Re: [linux-sunxi] [PATCH] ARM: sunxi: Fix CPU powerdown on A83T

[Chen-Yu Tsai]

On Tue, Oct 29, 2019 at 5:49 AM Ondrej Jirman <megous@megous.com> wrote:
>
> PRCM_PWROFF_GATING_REG has CPU0 at bit 4 on A83T. So without this
> patch, instead of gating the CPU0, the whole cluster was power gated,
> when shutting down first CPU in the cluster.
>
> Fixes: 6961275e72a8c1 ("ARM: sun8i: smp: Add support for A83T")
> Signed-off-by: Ondrej Jirman <megous@megous.com>
> Cc: stable@vger.kernel.org

Acked-by: Chen-Yu Tsai <wens@csie.org>

Though I distinctly remember the BSP had some code dealing with chip
revisions in which the two bits were reversed. :(

Re: [linux-sunxi] [PATCH] ARM: sunxi: Fix CPU powerdown on A83T

[Ondřej Jirman]

On Tue, Oct 29, 2019 at 09:09:40AM +0800, Chen-Yu Tsai wrote:
> On Tue, Oct 29, 2019 at 5:49 AM Ondrej Jirman <megous@megous.com> wrote:
> >
> > PRCM_PWROFF_GATING_REG has CPU0 at bit 4 on A83T. So without this
> > patch, instead of gating the CPU0, the whole cluster was power gated,
> > when shutting down first CPU in the cluster.
> >
> > Fixes: 6961275e72a8c1 ("ARM: sun8i: smp: Add support for A83T")
> > Signed-off-by: Ondrej Jirman <megous@megous.com>
> > Cc: stable@vger.kernel.org
> 
> Acked-by: Chen-Yu Tsai <wens@csie.org>
> 
> Though I distinctly remember the BSP had some code dealing with chip
> revisions in which the two bits were reversed. :(

Actually, it's a bit more complicated. There's a special check in BSP
code (grep for SUN8IW6P1_REV_A) that instead of power gating, just
holds the core in reset for that revision.

regards,
	o.

Re: [PATCH] ARM: sunxi: Fix CPU powerdown on A83T

[Maxime Ripard]

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On Mon, Oct 28, 2019 at 10:49:14PM +0100, Ondrej Jirman wrote:
> PRCM_PWROFF_GATING_REG has CPU0 at bit 4 on A83T. So without this
> patch, instead of gating the CPU0, the whole cluster was power gated,
> when shutting down first CPU in the cluster.
>
> Fixes: 6961275e72a8c1 ("ARM: sun8i: smp: Add support for A83T")
> Signed-off-by: Ondrej Jirman <megous@megous.com>
> Cc: stable@vger.kernel.org

Applied, thanks

Maxime

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