| Message ID | 1401700866-24804-2-git-send-email-antoine.tenart@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > diff --git a/arch/arm/mach-berlin/Kconfig b/arch/arm/mach-berlin/Kconfig > index d3c5f14dc142..e3733692f67a 100644 > --- a/arch/arm/mach-berlin/Kconfig > +++ b/arch/arm/mach-berlin/Kconfig > @@ -4,6 +4,7 @@ config ARCH_BERLIN > select GENERIC_IRQ_CHIP > select DW_APB_ICTL > select DW_APB_TIMER_OF > + select SMP Please don't add selects of symbols which aren't absolutely necessary. Since this has been merged without SMP support and presumably works without SMP support, it would appear that SMP support is not mandatory for the platform to work.
On Mon, Jun 02, 2014 at 10:29:13AM +0100, Russell King - ARM Linux wrote: > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > diff --git a/arch/arm/mach-berlin/Kconfig b/arch/arm/mach-berlin/Kconfig > > index d3c5f14dc142..e3733692f67a 100644 > > --- a/arch/arm/mach-berlin/Kconfig > > +++ b/arch/arm/mach-berlin/Kconfig > > @@ -4,6 +4,7 @@ config ARCH_BERLIN > > select GENERIC_IRQ_CHIP > > select DW_APB_ICTL > > select DW_APB_TIMER_OF > > + select SMP > > Please don't add selects of symbols which aren't absolutely necessary. > > Since this has been merged without SMP support and presumably works without > SMP support, it would appear that SMP support is not mandatory for the > platform to work. It can work without SMP, I'll remove this. Antoine
On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > + > +static inline void berlin_reset_cpu(unsigned int cpu) > +{ > + u32 val; > + > + val = readl(cpu_ctrl + CPU_RESET); > + val |= BIT(cpu_logical_map(cpu)); > + writel(val, cpu_ctrl + CPU_RESET); > +} Hi Antoine Is this performing a reset on the CPU, or is it taking it out of reset? If you are going to implement CPU hotplug at some point, you are going to want to be able to put the CPU into reset, i.e. power it off, and take it out of reset, i.e. power it on and getting it running. So it might help if we get these function names clear now. Andrew > + > +static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle) > +{ > + if (!cpu_ctrl) > + return -EFAULT; > + > + /* > + * Reset the CPU, making it to execute the instruction in the reset > + * exception register. > + */ > + berlin_reset_cpu(cpu); > + > + return 0; > +} > + > +static void __init berlin_smp_prepare_cpus(unsigned int max_cpus) > +{ > + struct device_node *np; > + void __iomem *scu_base; > + void __iomem *vectors_base; > + > + np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); > + scu_base = of_iomap(np, 0); > + of_node_put(np); > + if (!scu_base) > + return; > + > + np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl"); > + cpu_ctrl = of_iomap(np, 0); > + of_node_put(np); > + if (!cpu_ctrl) > + goto unmap_scu; > + > + vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K); > + if (!vectors_base) > + goto unmap_scu; > + > + scu_enable(scu_base); > + flush_cache_all(); > + > + /* > + * Write the first instruction the CPU will execute after being reseted > + * in the reset exception register. > + */ > + writel(boot_inst, vectors_base + RESET_VECT); > + > + /* > + * Write the secondary startup address into the SW reset address > + * register. This is used by boot_inst. Maybe it would be better to call this the reset address vector instead of address register. It is in the vector space after all. Andrew > + */ > + writel(virt_to_phys(berlin_secondary_startup), vectors_base + SW_RESET_ADDR); > + > + iounmap(vectors_base); > +unmap_scu: > + iounmap(scu_base); > +} > + > +static struct smp_operations berlin_smp_ops __initdata = { > + .smp_prepare_cpus = berlin_smp_prepare_cpus, > + .smp_boot_secondary = berlin_boot_secondary, > +}; > +CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops); > -- > 1.9.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hi Andrew, On Mon, Jun 02, 2014 at 11:47:15AM +0200, Andrew Lunn wrote: > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > + > > +static inline void berlin_reset_cpu(unsigned int cpu) > > +{ > > + u32 val; > > + > > + val = readl(cpu_ctrl + CPU_RESET); > > + val |= BIT(cpu_logical_map(cpu)); > > + writel(val, cpu_ctrl + CPU_RESET); > > +} > > Is this performing a reset on the CPU, or is it taking it out of reset? > > If you are going to implement CPU hotplug at some point, you are going > to want to be able to put the CPU into reset, i.e. power it off, and > take it out of reset, i.e. power it on and getting it running. So it > might help if we get these function names clear now. It is performing a reset on the CPU. berlin_perform_reset_cpu() then? > > + > > +static void __init berlin_smp_prepare_cpus(unsigned int max_cpus) > > +{ > > + struct device_node *np; > > + void __iomem *scu_base; > > + void __iomem *vectors_base; > > + > > + np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); > > + scu_base = of_iomap(np, 0); > > + of_node_put(np); > > + if (!scu_base) > > + return; > > + > > + np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl"); > > + cpu_ctrl = of_iomap(np, 0); > > + of_node_put(np); > > + if (!cpu_ctrl) > > + goto unmap_scu; > > + > > + vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K); > > + if (!vectors_base) > > + goto unmap_scu; > > + > > + scu_enable(scu_base); > > + flush_cache_all(); > > + > > + /* > > + * Write the first instruction the CPU will execute after being reseted > > + * in the reset exception register. > > + */ > > + writel(boot_inst, vectors_base + RESET_VECT); > > + > > + /* > > + * Write the secondary startup address into the SW reset address > > + * register. This is used by boot_inst. > > Maybe it would be better to call this the reset address vector instead > of address register. It is in the vector space after all. I don't have a strong opinion on this. I can update the 'reset exception register' as well then. Antoine
On Mon, Jun 02, 2014 at 12:00:48PM +0200, Antoine Ténart wrote: > Hi Andrew, > > On Mon, Jun 02, 2014 at 11:47:15AM +0200, Andrew Lunn wrote: > > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > > + > > > +static inline void berlin_reset_cpu(unsigned int cpu) > > > +{ > > > + u32 val; > > > + > > > + val = readl(cpu_ctrl + CPU_RESET); > > > + val |= BIT(cpu_logical_map(cpu)); > > > + writel(val, cpu_ctrl + CPU_RESET); > > > +} > > > > Is this performing a reset on the CPU, or is it taking it out of reset? > > > > If you are going to implement CPU hotplug at some point, you are going > > to want to be able to put the CPU into reset, i.e. power it off, and > > take it out of reset, i.e. power it on and getting it running. So it > > might help if we get these function names clear now. > > It is performing a reset on the CPU. berlin_perform_reset_cpu() then? Yes, that would be better. What happens if the CPU is powered off? Will a reset power it on? Or are you assuming the boot loader has powered it on? Andrew
On Mon, Jun 02, 2014 at 12:03:32PM +0200, Andrew Lunn wrote: > On Mon, Jun 02, 2014 at 12:00:48PM +0200, Antoine Ténart wrote: > > Hi Andrew, > > > > On Mon, Jun 02, 2014 at 11:47:15AM +0200, Andrew Lunn wrote: > > > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > > > + > > > > +static inline void berlin_reset_cpu(unsigned int cpu) > > > > +{ > > > > + u32 val; > > > > + > > > > + val = readl(cpu_ctrl + CPU_RESET); > > > > + val |= BIT(cpu_logical_map(cpu)); > > > > + writel(val, cpu_ctrl + CPU_RESET); > > > > +} > > > > > > Is this performing a reset on the CPU, or is it taking it out of reset? > > > > > > If you are going to implement CPU hotplug at some point, you are going > > > to want to be able to put the CPU into reset, i.e. power it off, and > > > take it out of reset, i.e. power it on and getting it running. So it > > > might help if we get these function names clear now. > > > > It is performing a reset on the CPU. berlin_perform_reset_cpu() then? > > What happens if the CPU is powered off? Will a reset power it on? Or > are you assuming the boot loader has powered it on? I actually don't have information about this. For now let's assume the boot loader has powered on the CPUs. Antoine
Hi Andrew, Antoine, On Mon, 2 Jun 2014 03:27:50 -0700 Antoine Ténart <antoine.tenart@free-electrons.com> wrote: > On Mon, Jun 02, 2014 at 12:03:32PM +0200, Andrew Lunn wrote: > > On Mon, Jun 02, 2014 at 12:00:48PM +0200, Antoine Ténart wrote: > > > Hi Andrew, > > > > > > On Mon, Jun 02, 2014 at 11:47:15AM +0200, Andrew Lunn wrote: > > > > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > > > > + > > > > > +static inline void berlin_reset_cpu(unsigned int cpu) > > > > > +{ > > > > > + u32 val; > > > > > + > > > > > + val = readl(cpu_ctrl + CPU_RESET); > > > > > + val |= BIT(cpu_logical_map(cpu)); > > > > > + writel(val, cpu_ctrl + CPU_RESET); > > > > > +} > > > > > > > > Is this performing a reset on the CPU, or is it taking it out of > > > > reset? > > > > > > > > If you are going to implement CPU hotplug at some point, you are going > > > > to want to be able to put the CPU into reset, i.e. power it off, and > > > > take it out of reset, i.e. power it on and getting it running. So it > > > > might help if we get these function names clear now. > > > > > > It is performing a reset on the CPU. berlin_perform_reset_cpu() then? > > > > What happens if the CPU is powered off? Will a reset power it on? Or > > are you assuming the boot loader has powered it on? > > I actually don't have information about this. For now let's assume the > boot loader has powered on the CPUs. > We don't support independently power off cpu on BG2 and BG2Q in linux kernel. So we can assume that bootloader has powered on the CPUs
Hi Antoine, On Mon, 2 Jun 2014 02:21:02 -0700 Antoine Ténart <antoine.tenart@free-electrons.com> wrote: > Adds SMP support for Berlin SoCs. Secondary CPUs are reseted, then > execute the instruction we put in the reset exception register, setting > the pc at the address contained in the software reset address register, > which is the physical address of the Berlin secondary startup. > > This implementation avoid using the pen lock mechanism. > > Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com> > --- > arch/arm/mach-berlin/Kconfig | 3 ++ > arch/arm/mach-berlin/Makefile | 3 +- > arch/arm/mach-berlin/headsmp.S | 30 +++++++++++++ > arch/arm/mach-berlin/platsmp.c | 99 > ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 134 > insertions(+), 1 deletion(-) create mode 100644 > arch/arm/mach-berlin/headsmp.S create mode 100644 > arch/arm/mach-berlin/platsmp.c > > diff --git a/arch/arm/mach-berlin/Kconfig b/arch/arm/mach-berlin/Kconfig > index d3c5f14dc142..e3733692f67a 100644 > --- a/arch/arm/mach-berlin/Kconfig > +++ b/arch/arm/mach-berlin/Kconfig > @@ -4,6 +4,7 @@ config ARCH_BERLIN > select GENERIC_IRQ_CHIP > select DW_APB_ICTL > select DW_APB_TIMER_OF > + select SMP > > if ARCH_BERLIN > > @@ -13,6 +14,7 @@ config MACH_BERLIN_BG2 > bool "Marvell Armada 1500 (BG2)" > select CACHE_L2X0 > select CPU_PJ4B > + select HAVE_ARM_SCU if SMP > select HAVE_ARM_TWD if SMP > > config MACH_BERLIN_BG2CD > @@ -24,6 +26,7 @@ config MACH_BERLIN_BG2Q > bool "Marvell Armada 1500 Pro (BG2-Q)" > select CACHE_L2X0 > select CPU_V7 > + select HAVE_ARM_SCU if SMP > select HAVE_ARM_TWD if SMP > select HAVE_SMP > > diff --git a/arch/arm/mach-berlin/Makefile b/arch/arm/mach-berlin/Makefile > index ab69fe956f49..c0719ecd1890 100644 > --- a/arch/arm/mach-berlin/Makefile > +++ b/arch/arm/mach-berlin/Makefile > @@ -1 +1,2 @@ > -obj-y += berlin.o > +obj-y += berlin.o > +obj-$(CONFIG_SMP) += headsmp.o platsmp.o > diff --git a/arch/arm/mach-berlin/headsmp.S b/arch/arm/mach-berlin/headsmp.S > new file mode 100644 > index 000000000000..d295b5185598 > --- /dev/null > +++ b/arch/arm/mach-berlin/headsmp.S > @@ -0,0 +1,30 @@ > +/* > + * Copyright (C) 2014 Marvell Technology Group Ltd. > + * > + * Antoine Ténart <antoine.tenart@free-electrons.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include <linux/linkage.h> > +#include <linux/init.h> > +#include <asm/assembler.h> > + > +ENTRY(berlin_secondary_startup) > + ARM_BE8(setend be) > + bl v7_invalidate_l1 > + b secondary_startup > +ENDPROC(berlin_secondary_startup) > + > +/* > + * If the following instruction is set in the reset exception register, > CPUs > + * will fetch the value of the software reset address register when being > + * reseted. > + */ > +.global boot_inst > +boot_inst: > + ldr pc, [pc, #140] > + > + .align > diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c > new file mode 100644 > index 000000000000..c04c90b81ae3 > --- /dev/null > +++ b/arch/arm/mach-berlin/platsmp.c > @@ -0,0 +1,99 @@ > +/* > + * Copyright (C) 2014 Marvell Technology Group Ltd. > + * > + * Antoine Ténart <antoine.tenart@free-electrons.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include <linux/io.h> > +#include <linux/delay.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > + > +#include <asm/cacheflush.h> > +#include <asm/smp_plat.h> > +#include <asm/smp_scu.h> > + > +#define CPU_RESET 0x00 > + > +#define RESET_VECT 0x00 > +#define SW_RESET_ADDR 0x94 > + > +extern void berlin_secondary_startup(void); > +extern u32 boot_inst; > + > +static void __iomem *cpu_ctrl; > + > +static inline void berlin_reset_cpu(unsigned int cpu) > +{ > + u32 val; > + > + val = readl(cpu_ctrl + CPU_RESET); > + val |= BIT(cpu_logical_map(cpu)); > + writel(val, cpu_ctrl + CPU_RESET); "writel(BIT(cpu_logical_map(cpu)), cpu_ctrl + CPU_RESET)" is enough. we don't need to read and modify, because we writing 0 has no any effect. > +} > + > +static int berlin_boot_secondary(unsigned int cpu, struct task_struct > *idle) +{ > + if (!cpu_ctrl) > + return -EFAULT; > + > + /* > + * Reset the CPU, making it to execute the instruction in the reset > + * exception register. > + */ > + berlin_reset_cpu(cpu); > + > + return 0; > +} > + > +static void __init berlin_smp_prepare_cpus(unsigned int max_cpus) > +{ > + struct device_node *np; > + void __iomem *scu_base; > + void __iomem *vectors_base; > + > + np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); > + scu_base = of_iomap(np, 0); > + of_node_put(np); > + if (!scu_base) > + return; > + > + np = of_find_compatible_node(NULL, NULL, > "marvell,berlin-cpu-ctrl"); > + cpu_ctrl = of_iomap(np, 0); > + of_node_put(np); > + if (!cpu_ctrl) > + goto unmap_scu; > + > + vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K); > + if (!vectors_base) > + goto unmap_scu; > + > + scu_enable(scu_base); > + flush_cache_all(); > + > + /* > + * Write the first instruction the CPU will execute after being > reseted > + * in the reset exception register. > + */ > + writel(boot_inst, vectors_base + RESET_VECT); Is it better to let bootloader/firmware handle this writing. Then, we can also remove the tricky boot_inst in headsmp.S. Many thanks for this patch, Jisheng
Hi Jisheng, On Tue, Jun 03, 2014 at 02:31:13PM +0800, Jisheng Zhang wrote: > On Mon, 2 Jun 2014 02:21:02 -0700 > Antoine Ténart <antoine.tenart@free-electrons.com> wrote: > > + > > +extern void berlin_secondary_startup(void); > > +extern u32 boot_inst; > > + > > +static void __iomem *cpu_ctrl; > > + > > +static inline void berlin_reset_cpu(unsigned int cpu) > > +{ > > + u32 val; > > + > > + val = readl(cpu_ctrl + CPU_RESET); > > + val |= BIT(cpu_logical_map(cpu)); > > + writel(val, cpu_ctrl + CPU_RESET); > > "writel(BIT(cpu_logical_map(cpu)), cpu_ctrl + CPU_RESET)" is enough. > we don't need to read and modify, because we writing 0 has no any effect. The reset bit is automatically cleared but I dumped the register value and it wasn't 0x0, that's why I preferred to read first and only set the reset bit. > > + > > + /* > > + * Write the first instruction the CPU will execute after being > > reseted > > + * in the reset exception register. > > + */ > > + writel(boot_inst, vectors_base + RESET_VECT); > > Is it better to let bootloader/firmware handle this writing. Then, we can > also remove the tricky boot_inst in headsmp.S. We thought about it, and since it can be difficult to update the bootloader for some boards, like BG2 based ones, we preferred to include this here. Thanks! Antoine
On Tue, 3 Jun 2014 00:10:17 -0700 Antoine Ténart <antoine.tenart@free-electrons.com> wrote: > Hi Jisheng, > > On Tue, Jun 03, 2014 at 02:31:13PM +0800, Jisheng Zhang wrote: > > On Mon, 2 Jun 2014 02:21:02 -0700 > > Antoine Ténart <antoine.tenart@free-electrons.com> wrote: > > > + > > > +extern void berlin_secondary_startup(void); > > > +extern u32 boot_inst; > > > + > > > +static void __iomem *cpu_ctrl; > > > + > > > +static inline void berlin_reset_cpu(unsigned int cpu) > > > +{ > > > + u32 val; > > > + > > > + val = readl(cpu_ctrl + CPU_RESET); > > > + val |= BIT(cpu_logical_map(cpu)); > > > + writel(val, cpu_ctrl + CPU_RESET); > > > > "writel(BIT(cpu_logical_map(cpu)), cpu_ctrl + CPU_RESET)" is enough. > > we don't need to read and modify, because we writing 0 has no any effect. > > The reset bit is automatically cleared but I dumped the register value > and it wasn't 0x0, that's why I preferred to read first and only set the > reset bit. > > > > + > > > + /* > > > + * Write the first instruction the CPU will execute after being > > > reseted > > > + * in the reset exception register. > > > + */ > > > + writel(boot_inst, vectors_base + RESET_VECT); > > > > Is it better to let bootloader/firmware handle this writing. Then, we can > > also remove the tricky boot_inst in headsmp.S. > > We thought about it, and since it can be difficult to update the > bootloader for some boards, like BG2 based ones, we preferred to include > this here. > > Thanks! > > Antoine > Got your points. Thanks very much
> We don't support independently power off cpu on BG2 and BG2Q in linux kernel. > So we can assume that bootloader has powered on the CPUs Can i assume from your answer that the hardware does actually support independent power off/on of CPUs? It could be added sometime in the future. Andrew
Hi Andrew, On Tue, 3 Jun 2014 00:50:11 -0700 Andrew Lunn <andrew@lunn.ch> wrote: > > We don't support independently power off cpu on BG2 and BG2Q in linux > > kernel. So we can assume that bootloader has powered on the CPUs > > Can i assume from your answer that the hardware does actually support > independent power off/on of CPUs? It could be added sometime in the > future. > The BG2 and BG2Q HW doesn't support independent power off/on CPUs. Sorry for confusion, Jisheng
diff --git a/arch/arm/mach-berlin/Kconfig b/arch/arm/mach-berlin/Kconfig index d3c5f14dc142..e3733692f67a 100644 --- a/arch/arm/mach-berlin/Kconfig +++ b/arch/arm/mach-berlin/Kconfig @@ -4,6 +4,7 @@ config ARCH_BERLIN select GENERIC_IRQ_CHIP select DW_APB_ICTL select DW_APB_TIMER_OF + select SMP if ARCH_BERLIN @@ -13,6 +14,7 @@ config MACH_BERLIN_BG2 bool "Marvell Armada 1500 (BG2)" select CACHE_L2X0 select CPU_PJ4B + select HAVE_ARM_SCU if SMP select HAVE_ARM_TWD if SMP config MACH_BERLIN_BG2CD @@ -24,6 +26,7 @@ config MACH_BERLIN_BG2Q bool "Marvell Armada 1500 Pro (BG2-Q)" select CACHE_L2X0 select CPU_V7 + select HAVE_ARM_SCU if SMP select HAVE_ARM_TWD if SMP select HAVE_SMP diff --git a/arch/arm/mach-berlin/Makefile b/arch/arm/mach-berlin/Makefile index ab69fe956f49..c0719ecd1890 100644 --- a/arch/arm/mach-berlin/Makefile +++ b/arch/arm/mach-berlin/Makefile @@ -1 +1,2 @@ -obj-y += berlin.o +obj-y += berlin.o +obj-$(CONFIG_SMP) += headsmp.o platsmp.o diff --git a/arch/arm/mach-berlin/headsmp.S b/arch/arm/mach-berlin/headsmp.S new file mode 100644 index 000000000000..d295b5185598 --- /dev/null +++ b/arch/arm/mach-berlin/headsmp.S @@ -0,0 +1,30 @@ +/* + * Copyright (C) 2014 Marvell Technology Group Ltd. + * + * Antoine Ténart <antoine.tenart@free-electrons.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/linkage.h> +#include <linux/init.h> +#include <asm/assembler.h> + +ENTRY(berlin_secondary_startup) + ARM_BE8(setend be) + bl v7_invalidate_l1 + b secondary_startup +ENDPROC(berlin_secondary_startup) + +/* + * If the following instruction is set in the reset exception register, CPUs + * will fetch the value of the software reset address register when being + * reseted. + */ +.global boot_inst +boot_inst: + ldr pc, [pc, #140] + + .align diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c new file mode 100644 index 000000000000..c04c90b81ae3 --- /dev/null +++ b/arch/arm/mach-berlin/platsmp.c @@ -0,0 +1,99 @@ +/* + * Copyright (C) 2014 Marvell Technology Group Ltd. + * + * Antoine Ténart <antoine.tenart@free-electrons.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/of.h> +#include <linux/of_address.h> + +#include <asm/cacheflush.h> +#include <asm/smp_plat.h> +#include <asm/smp_scu.h> + +#define CPU_RESET 0x00 + +#define RESET_VECT 0x00 +#define SW_RESET_ADDR 0x94 + +extern void berlin_secondary_startup(void); +extern u32 boot_inst; + +static void __iomem *cpu_ctrl; + +static inline void berlin_reset_cpu(unsigned int cpu) +{ + u32 val; + + val = readl(cpu_ctrl + CPU_RESET); + val |= BIT(cpu_logical_map(cpu)); + writel(val, cpu_ctrl + CPU_RESET); +} + +static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + if (!cpu_ctrl) + return -EFAULT; + + /* + * Reset the CPU, making it to execute the instruction in the reset + * exception register. + */ + berlin_reset_cpu(cpu); + + return 0; +} + +static void __init berlin_smp_prepare_cpus(unsigned int max_cpus) +{ + struct device_node *np; + void __iomem *scu_base; + void __iomem *vectors_base; + + np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); + scu_base = of_iomap(np, 0); + of_node_put(np); + if (!scu_base) + return; + + np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl"); + cpu_ctrl = of_iomap(np, 0); + of_node_put(np); + if (!cpu_ctrl) + goto unmap_scu; + + vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K); + if (!vectors_base) + goto unmap_scu; + + scu_enable(scu_base); + flush_cache_all(); + + /* + * Write the first instruction the CPU will execute after being reseted + * in the reset exception register. + */ + writel(boot_inst, vectors_base + RESET_VECT); + + /* + * Write the secondary startup address into the SW reset address + * register. This is used by boot_inst. + */ + writel(virt_to_phys(berlin_secondary_startup), vectors_base + SW_RESET_ADDR); + + iounmap(vectors_base); +unmap_scu: + iounmap(scu_base); +} + +static struct smp_operations berlin_smp_ops __initdata = { + .smp_prepare_cpus = berlin_smp_prepare_cpus, + .smp_boot_secondary = berlin_boot_secondary, +}; +CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);
Adds SMP support for Berlin SoCs. Secondary CPUs are reseted, then execute the instruction we put in the reset exception register, setting the pc at the address contained in the software reset address register, which is the physical address of the Berlin secondary startup. This implementation avoid using the pen lock mechanism. Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com> --- arch/arm/mach-berlin/Kconfig | 3 ++ arch/arm/mach-berlin/Makefile | 3 +- arch/arm/mach-berlin/headsmp.S | 30 +++++++++++++ arch/arm/mach-berlin/platsmp.c | 99 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 134 insertions(+), 1 deletion(-) create mode 100644 arch/arm/mach-berlin/headsmp.S create mode 100644 arch/arm/mach-berlin/platsmp.c