Subject: [PATCH V5 1/5] arm: mvebu: Added support for coherency fabric in mach-mvebu

From: [email-masked] (Gregory CLEMENT)
Date: Wed, 21 Nov 2012 15:12:37 +0100

On 11/21/2012 11:36 AM, Will Deacon wrote:
> On Tue, Nov 20, 2012 at 09:15:45PM +0000, Gregory CLEMENT wrote:
>> From: Yehuda Yitschak <[email-masked]>
> 
> <insert commit log here>
> 
> Also -- is the author attribution still correct?
> 
>> Signed-off-by: Yehuda Yitschak <[email-masked]>
>> Signed-off-by: Gregory CLEMENT <[email-masked]>
>> ---
>>  .../devicetree/bindings/arm/coherency-fabric.txt   |   16 ++++
>>  arch/arm/boot/dts/armada-370-xp.dtsi               |    5 ++
>>  arch/arm/mach-mvebu/Makefile                       |    2 +-
>>  arch/arm/mach-mvebu/coherency.c                    |   80 ++++++++++++++++++++
>>  arch/arm/mach-mvebu/coherency.h                    |   24 ++++++
>>  arch/arm/mach-mvebu/coherency_ll.S                 |   47 ++++++++++++
>>  arch/arm/mach-mvebu/common.h                       |    2 +
>>  7 files changed, 175 insertions(+), 1 deletion(-)
>>  create mode 100644 Documentation/devicetree/bindings/arm/coherency-fabric.txt
>>  create mode 100644 arch/arm/mach-mvebu/coherency.c
>>  create mode 100644 arch/arm/mach-mvebu/coherency.h
>>  create mode 100644 arch/arm/mach-mvebu/coherency_ll.S
>>
>> diff --git a/Documentation/devicetree/bindings/arm/coherency-fabric.txt b/Documentation/devicetree/bindings/arm/coherency-fabric.txt
>> new file mode 100644
>> index 0000000..2bfbf67
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/coherency-fabric.txt
>> @@ -0,0 +1,16 @@
>> +Coherency fabric
>> +----------------
>> +Available on Marvell SOCs: Armada 370 and Armada XP
>> +
>> +Required properties:
>> +
>> +- compatible: "marvell,coherency-fabric"
>> +- reg: Should contain,coherency fabric registers location and length.
>> +
>> +Example:
>> +
>> +coherency-fabric at d0020200 {
>> +	compatible = "marvell,coherency-fabric";
>> +	reg = <0xd0020200 0xb0>;
>> +};
>> +
>> diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
>> index 94b4b9e..b0d075b 100644
>> --- a/arch/arm/boot/dts/armada-370-xp.dtsi
>> +++ b/arch/arm/boot/dts/armada-370-xp.dtsi
>> @@ -36,6 +36,11 @@
>>  	      interrupt-controller;
>>  	};
>>  
>> +	coherency-fabric at d0020200 {
>> +		compatible = "marvell,coherency-fabric";
>> +		reg = <0xd0020200 0xb0>;
>> +	};
>> +
>>  	soc {
>>  		#address-cells = <1>;
>>  		#size-cells = <1>;
>> diff --git a/arch/arm/mach-mvebu/Makefile b/arch/arm/mach-mvebu/Makefile
>> index 57f996b..5ce4b42 100644
>> --- a/arch/arm/mach-mvebu/Makefile
>> +++ b/arch/arm/mach-mvebu/Makefile
>> @@ -2,4 +2,4 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
>>  	-I$(srctree)/arch/arm/plat-orion/include
>>  
>>  obj-y += system-controller.o
>> -obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o irq-armada-370-xp.o addr-map.o
>> +obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o irq-armada-370-xp.o addr-map.o coherency.o coherency_ll.o
>> diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
>> new file mode 100644
>> index 0000000..1bc02d0
>> --- /dev/null
>> +++ b/arch/arm/mach-mvebu/coherency.c
>> @@ -0,0 +1,80 @@
>> +/*
>> + * Coherency fabric (Aurora) support for Armada 370 and XP platforms.
>> + *
>> + * Copyright (C) 2012 Marvell
>> + *
>> + * Yehuda Yitschak <[email-masked]>
>> + * Gregory Clement <[email-masked]>
>> + * Thomas Petazzoni <[email-masked]>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2.  This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + *
>> + * The Armada 370 and Armada XP SOCs have a coherency fabric which is
>> + * responsible for ensuring hardware coherency between all CPUs and between
>> + * CPUs and I/O masters. This file initializes the coherency fabric and
>> + * supplies basic routines for configuring and controlling hardware coherency
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/of_address.h>
>> +#include <linux/io.h>
>> +#include <linux/smp.h>
>> +#include <asm/smp_plat.h>
>> +#include "armada-370-xp.h"
>> +
>> +/* Some functions in this file are called very early during SMP
>> + * initialization. At that time the device tree framework is not yet
>> + * ready, and it is not possible to get the register address to
>> + * ioremap it. That's why the pointer below is given with an initial
>> + * value matching its virtual mapping
>> + */
>> +static void __iomem *coherency_base = ARMADA_370_XP_REGS_VIRT_BASE + 0x20200;
>> +
>> +/* Coherency fabric registers */
>> +#define COHERENCY_FABRIC_CFG_OFFSET		   0x4
>> +
>> +static struct of_device_id of_coherency_table[] = {
>> +	{.compatible = "marvell,coherency-fabric"},
>> +	{ /* end of list */ },
>> +};
>> +#ifdef CONFIG_SMP
>> +int coherency_get_cpu_count(void)
>> +{
>> +	int reg, cnt;
>> +
>> +	reg = readl(coherency_base + COHERENCY_FABRIC_CFG_OFFSET);
>> +	cnt = (reg & 0xF) + 1;
>> +
>> +	return cnt;
>> +}
>> +#endif
>> +/* Function defined in coherncy_ll.S */
> 
> coherency_ll.S
> 
>> +extern void ll_set_cpu_coherent(void __iomem *base_addr,
>> +				unsigned int hw_cpu_id);
>> +
>> +int set_cpu_coherent(unsigned int hw_cpu_id, int smp_group_id)
>> +{
>> +	if (!coherency_base) {
>> +		pr_warn("Can't make CPU %d cache coherent.\n", hw_cpu_id);
>> +		pr_warn("Coherency fabric is not initialized\n");
>> +		return 1;
>> +	}
>> +	ll_set_cpu_coherent(coherency_base, hw_cpu_id);
>> +	return 0;
> 
> You can just do return ll_set_cpu_coherent(...) now.
> 
>> +}
>> +
>> +int __init coherency_init(void)
>> +{
>> +	struct device_node *np;
>> +
>> +	np = of_find_matching_node(NULL, of_coherency_table);
>> +	if (np) {
>> +		pr_info("Initializing Coherency fabric\n");
>> +		coherency_base = of_iomap(np, 0);
>> +	}
>> +
>> +	return 0;
>> +}
>> diff --git a/arch/arm/mach-mvebu/coherency.h b/arch/arm/mach-mvebu/coherency.h
>> new file mode 100644
>> index 0000000..2f42813
>> --- /dev/null
>> +++ b/arch/arm/mach-mvebu/coherency.h
>> @@ -0,0 +1,24 @@
>> +/*
>> + * arch/arm/mach-mvebu/include/mach/coherency.h
>> + *
>> + *
>> + * Coherency fabric (Aurora) support for Armada 370 and XP platforms.
>> + *
>> + * Copyright (C) 2012 Marvell
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2.  This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +#ifndef __MACH_370_XP_COHERENCY_H
>> +#define __MACH_370_XP_COHERENCY_H
>> +
>> +#ifdef CONFIG_SMP
>> +int coherency_get_cpu_count(void);
>> +#endif
>> +
>> +int set_cpu_coherent(int cpu_id, int smp_group_id);
>> +int coherency_init(void);
>> +
>> +#endif	/* __MACH_370_XP_COHERENCY_H */
>> diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S
>> new file mode 100644
>> index 0000000..ae48730
>> --- /dev/null
>> +++ b/arch/arm/mach-mvebu/coherency_ll.S
>> @@ -0,0 +1,47 @@
>> +/*
>> + * Coherency fabric: low level functions
>> + *
>> + * Copyright (C) 2012 Marvell
>> + *
>> + * Gregory CLEMENT <[email-masked]>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2.  This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + *
>> + * This file implements the assembly function to add a CPU to the
>> + * coherency fabric. This function is called by each of the secondary
>> + * CPUs during their early boot in an SMP kernel, this why this
>> + * function have to callable from assembly. It can also be called by a
>> + * primary CPU from C code during its boot.
>> + */
>> +
>> +#include <linux/linkage.h>
>> +#define ARMADA_XP_CFB_CTL_REG_OFFSET 0x0
>> +#define ARMADA_XP_CFB_CFG_REG_OFFSET 0x4
>> +
>> +	.text
>> +/*
>> + * r0: Coherency fabric base register address
>> + * r1: HW CPU id
>> + */
>> +ENTRY(ll_set_cpu_coherent)
>> +	/* Create bit by cpu index */
>> +	mov	r3, #(1 << 24)
>> +	lsl     r1, r3, r1
>> +
>> +	/* Add CPU to SMP group - Atomic */
>> +	add	r3, r0, #ARMADA_XP_CFB_CTL_REG_OFFSET
>> +	ldr     r2, [r3]
>> +	orr     r2, r2, r1
>> +	str	r2, [r0]
>> +
>> +	/* Enable coherency on CPU - Atomic */
>> +	add	r3, r0, #ARMADA_XP_CFB_CFG_REG_OFFSET
>> +	ldr     r2, [r3]
>> +	orr     r2, r2, r1
>> +	str     r2, [r3]
> 
> I forgot to mention this before, but do you need a dsb or something here?

The answer from Marvell engineer:
"Especially for this case, DSB is not needed because we set the MMU to
be such that these configurations are in SO memory space.  However, I
agree with the comment and believe that it would be good practice to
add a DSB at the end of this sequence (and not rely on the fact that
it they are not under DEVICE memory space)"

So in short I will add a dsb here.

> Will

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