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Message-ID: <20160826111356.GM1041@n2100.armlinux.org.uk>
Date: Fri, 26 Aug 2016 12:13:57 +0100
From: Russell King - ARM Linux <linux@...linux.org.uk>
To: Anson Huang <Anson.Huang@....com>
Cc: linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, shawnguo@...nel.org,
kernel@...gutronix.de, fabio.estevam@....com, robh+dt@...nel.org,
mark.rutland@....com
Subject: Re: [PATCH 3/3] ARM: imx: add SMP support for i.MX7D
On Fri, Aug 26, 2016 at 07:12:51PM +0800, Anson Huang wrote:
> i.MX7D has 2 cortex-a7 ARM core, add support for
> booting up SMP kernel with 2 CPUs.
>
> The existing i.MX SMP code is designed for i.MX6
> series SoCs which have cortex-a9 ARM core, but i.MX7D
> has 2 cortex-a7 ARM core, so we need to add runtime
> check for those differences between cortex-a9 and
> cortex-a7.
>
> Signed-off-by: Anson Huang <Anson.Huang@....com>
> ---
> arch/arm/mach-imx/headsmp.S | 11 +++++++++++
> arch/arm/mach-imx/mach-imx7d.c | 2 ++
> arch/arm/mach-imx/platsmp.c | 19 ++++++++++++++++++-
> arch/arm/mach-imx/src.c | 38 ++++++++++++++++++++++++++++++--------
> 4 files changed, 61 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/mach-imx/headsmp.S b/arch/arm/mach-imx/headsmp.S
> index 6c28d28..a26e459 100644
> --- a/arch/arm/mach-imx/headsmp.S
> +++ b/arch/arm/mach-imx/headsmp.S
> @@ -26,7 +26,18 @@ diag_reg_offset:
> .endm
>
> ENTRY(v7_secondary_startup)
> + .word 0xc070 @ 0xc07 is cortex-a7 id
> + .word 0xfff0 @ mask for core type
> +
> ARM_BE8(setend be) @ go BE8 if entered LE
> + mrc p15, 0, r0, c0, c0, 0
> + adr r1, v7_secondary_startup
> + ldr r2, [r1]
> + ldr r3, [r1, #0x4]
> + and r0, r0, r3
> + cmp r0, r2
> + beq secondary_startup
> +
Total NAK on the above. There's no way that we want to even try
executing those two .word values (and I don't care if "it works
when tested", we just don't try and execute data.)
> set_diag_reg
> b secondary_startup
> ENDPROC(v7_secondary_startup)
> diff --git a/arch/arm/mach-imx/mach-imx7d.c b/arch/arm/mach-imx/mach-imx7d.c
> index 26ca744..ef3dce6 100644
> --- a/arch/arm/mach-imx/mach-imx7d.c
> +++ b/arch/arm/mach-imx/mach-imx7d.c
> @@ -99,6 +99,7 @@ static void __init imx7d_init_machine(void)
>
> static void __init imx7d_init_irq(void)
> {
> + imx_gpcv2_check_dt();
> imx_init_revision_from_anatop();
> imx_src_init();
> irqchip_init();
> @@ -111,6 +112,7 @@ static const char *const imx7d_dt_compat[] __initconst = {
> };
>
> DT_MACHINE_START(IMX7D, "Freescale i.MX7 Dual (Device Tree)")
> + .smp = smp_ops(imx_smp_ops),
> .init_irq = imx7d_init_irq,
> .init_machine = imx7d_init_machine,
> .dt_compat = imx7d_dt_compat,
> diff --git a/arch/arm/mach-imx/platsmp.c b/arch/arm/mach-imx/platsmp.c
> index 711dbbd..63af911 100644
> --- a/arch/arm/mach-imx/platsmp.c
> +++ b/arch/arm/mach-imx/platsmp.c
> @@ -60,8 +60,17 @@ static int imx_boot_secondary(unsigned int cpu, struct task_struct *idle)
> static void __init imx_smp_init_cpus(void)
> {
> int i, ncores;
> + unsigned long val, arch_type;
>
> - ncores = scu_get_core_count(scu_base);
> + asm volatile("mrc p15, 0, %0, c0, c0, 0" : "=r" (arch_type));
> +
> + if (((arch_type >> 4) & 0xfff) == 0xc07) {
This is buggy. Plus, we have macros for this. Please use the
macros in asm/cputype.h to achieve these tests.
> + /* cortex-a7 core number is in bit[25:24] of CP15 L2CTLR */
> + asm volatile("mrc p15, 1, %0, c9, c0, 2" : "=r" (val));
> + ncores = ((val >> 24) & 0x3) + 1;
> + } else {
> + ncores = scu_get_core_count(scu_base);
> + }
>
> for (i = ncores; i < NR_CPUS; i++)
> set_cpu_possible(i, false);
> @@ -74,6 +83,14 @@ void imx_smp_prepare(void)
>
> static void __init imx_smp_prepare_cpus(unsigned int max_cpus)
> {
> + unsigned long arch_type;
> +
> + asm volatile("mrc p15, 0, %0, c0, c0, 0" : "=r" (arch_type));
> +
> + /* no need for cortex-a7 */
> + if (((arch_type >> 4) & 0xfff) == 0xc07)
Ditto.
> + return;
> +
> imx_smp_prepare();
>
> /*
> diff --git a/arch/arm/mach-imx/src.c b/arch/arm/mach-imx/src.c
> index 70b083f..1fda72a 100644
> --- a/arch/arm/mach-imx/src.c
> +++ b/arch/arm/mach-imx/src.c
> @@ -18,6 +18,7 @@
> #include <linux/smp.h>
> #include <asm/smp_plat.h>
> #include "common.h"
> +#include "hardware.h"
>
> #define SRC_SCR 0x000
> #define SRC_GPR1 0x020
> @@ -30,6 +31,15 @@
> #define BP_SRC_SCR_CORE1_RST 14
> #define BP_SRC_SCR_CORE1_ENABLE 22
>
> +/* below are for i.MX7D */
> +#define SRC_GPR1_V2 0x074
> +#define SRC_A7RCR0 0x004
> +#define SRC_A7RCR1 0x008
> +#define SRC_M4RCR 0x00C
> +
> +#define BP_SRC_A7RCR0_A7_CORE_RESET0 0
> +#define BP_SRC_A7RCR1_A7_CORE1_ENABLE 1
> +
> static void __iomem *src_base;
> static DEFINE_SPINLOCK(scr_lock);
>
> @@ -87,12 +97,21 @@ void imx_enable_cpu(int cpu, bool enable)
> u32 mask, val;
>
> cpu = cpu_logical_map(cpu);
> - mask = 1 << (BP_SRC_SCR_CORE1_ENABLE + cpu - 1);
> spin_lock(&scr_lock);
> - val = readl_relaxed(src_base + SRC_SCR);
> - val = enable ? val | mask : val & ~mask;
> - val |= 1 << (BP_SRC_SCR_CORE1_RST + cpu - 1);
> - writel_relaxed(val, src_base + SRC_SCR);
> + if (cpu_is_imx7d()) {
It's about time iMX folk learned that "imx*" is a SoC and _not_ a CPU.
It should be "soc_is_imx7d()" because we're wanting to know whether
the _SoC_ is an iMX7D. The _CPU_ is a _Cortex-A7_.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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