Subject: [PATCH v2 1/2] ARM: mvebu: Add support to get the ID and the revision of a SoC

From: [email-masked] (Gregory CLEMENT)
Date: Fri, 03 Jan 2014 15:51:42 +0100

On 03/01/2014 15:47, Andrew Lunn wrote:
> On Fri, Jan 03, 2014 at 10:59:44AM +0100, Gregory CLEMENT wrote:
>> All the mvebu SoCs have information related to their variant and
>> revision that can be read from the PCI control register.
>>
>> This patch adds support for Armada XP and Armada 370. This reading of
>> the revision and the ID are done before the PCI initialization to
>> avoid any conflicts. Once these data are retrieved, the resources are
>> freed to let the PCI subsystem use it.
>>
>> Cc: stable at vger.kernel.org
>> Signed-off-by: Gregory CLEMENT <[email-masked]>
>> ---
>>  arch/arm/mach-mvebu/Makefile       |   2 +-
>>  arch/arm/mach-mvebu/mvebu-soc-id.c | 111 +++++++++++++++++++++++++++++++++++++
>>  include/linux/mvebu-soc-id.h       |  32 +++++++++++
>>  3 files changed, 144 insertions(+), 1 deletion(-)
>>  create mode 100644 arch/arm/mach-mvebu/mvebu-soc-id.c
>>  create mode 100644 include/linux/mvebu-soc-id.h
>>
>> diff --git a/arch/arm/mach-mvebu/Makefile b/arch/arm/mach-mvebu/Makefile
>> index 2d04f0e21870..878aebe98dcc 100644
>> --- a/arch/arm/mach-mvebu/Makefile
>> +++ b/arch/arm/mach-mvebu/Makefile
>> @@ -3,7 +3,7 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
>>  
>>  AFLAGS_coherency_ll.o		:= -Wa,-march=armv7-a
>>  
>> -obj-y				 += system-controller.o
>> +obj-y				 += system-controller.o mvebu-soc-id.o
>>  obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o
>>  obj-$(CONFIG_ARCH_MVEBU)	 += coherency.o coherency_ll.o pmsu.o
>>  obj-$(CONFIG_SMP)                += platsmp.o headsmp.o
>> diff --git a/arch/arm/mach-mvebu/mvebu-soc-id.c b/arch/arm/mach-mvebu/mvebu-soc-id.c
>> new file mode 100644
>> index 000000000000..86c901be284c
>> --- /dev/null
>> +++ b/arch/arm/mach-mvebu/mvebu-soc-id.c
>> @@ -0,0 +1,111 @@
>> +/*
>> + * Variant and revision information for mvebu SoCs
>> + *
>> + * Copyright (C) 2014 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.
>> + *
>> + * All the mvebu SoCs have information related to their variant and
>> + * revision that can be read from the PCI control register. This is
>> + * done before the PCI initialization to avoid any conflict. Once the
>> + * ID and revision are retrieved, the mapping is freed.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/init.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mvebu-soc-id.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +
>> +#define PCIE_DEV_ID_OFF		0x0
>> +#define PCIE_DEV_REV_OFF	0x8
>> +
>> +#define SOC_ID_MASK	    0xFFFF0000
>> +#define SOC_REV_MASK	    0xFF
>> +
>> +static u32 soc_dev_id;
>> +static u32 soc_rev;
>> +static bool is_id_valid;
>> +
>> +static const struct of_device_id mvebu_pcie_of_match_table[] = {
>> +	{ .compatible = "marvell,armada-xp-pcie", },
>> +	{ .compatible = "marvell,armada-370-pcie", },
>> +	{},
>> +};
>> +
>> +int mvebu_get_soc_id(u32 *dev, u32 *rev)
>> +{
>> +	if (is_id_valid) {
>> +		*dev = soc_dev_id;
>> +		*rev = soc_rev;
>> +		return 0;
>> +	} else
>> +		return -1;
>> +}
>> +
>> +EXPORT_SYMBOL(mvebu_get_soc_id);
>> +
>> +static int __init mvebu_soc_id_init(void)
>> +{
>> +	struct device_node *np;
>> +	int ret = 0;
>> +
>> +	np = of_find_matching_node(NULL, mvebu_pcie_of_match_table);
>> +	if (np) {
>> +		void __iomem *pci_base;
>> +		struct clk *clk;
>> +		/*
>> +		 * ID and revision are available from any port, so we
>> +		 * just pick the first one
>> +		 */
>> +		struct device_node *child = of_get_next_child(np, NULL);
> 
> Hi Gregory
> 
> I'm away from my hardware at the moment. 
> 
> Does this work when all the PCIe ports have status = "disabled";? We
> have many kirkwood devices in NAS boxes which don't use PCIe, so all
> the ports are disabled. But they still exist in the SoC, so we can
> read the IDs from them. I just don't know if of_get_next_child() will
> only return enabled children?

There is a function named of_get_next_available_child, so I assumed that
of_get_next_child() will return all the children. But I can test it to
be sure of it.

> 
> Thanks
> 	Andrew
> 
>> +
>> +		clk = of_clk_get_by_name(child, NULL);
>> +		if (IS_ERR(clk)) {
>> +			pr_err("%s: cannot get clock\n", __func__);
>> +			ret = -ENOMEM;
>> +			goto clk_err;
>> +		}
>> +
>> +		ret = clk_prepare_enable(clk);
>> +		if (ret) {
>> +			pr_err("%s: cannot enable clock\n", __func__);
>> +			goto clk_err;
>> +		}
>> +
>> +		pci_base = of_iomap(child, 0);
>> +		if (IS_ERR(pci_base)) {
>> +			pr_err("%s: cannot map registers\n",  __func__);
>> +			ret = -ENOMEM;
>> +			goto res_ioremap;
>> +		}
>> +
>> +		/* SoC ID */
>> +		soc_dev_id = __raw_readl(pci_base + PCIE_DEV_ID_OFF) >> 16;
>> +
>> +		/* SoC revision */
>> +		soc_rev = __raw_readl(pci_base + PCIE_DEV_REV_OFF)
>> +			& SOC_REV_MASK;
>> +
>> +		is_id_valid = true;
>> +
>> +		iounmap(pci_base);
>> +
>> +res_ioremap:
>> +		clk_disable_unprepare(clk);
>> +
>> +clk_err:
>> +		of_node_put(child);
>> +		of_node_put(np);
>> +	}
>> +
>> +	return ret;
>> +}
>> +arch_initcall(mvebu_soc_id_init);
>> +
>> diff --git a/include/linux/mvebu-soc-id.h b/include/linux/mvebu-soc-id.h
>> new file mode 100644
>> index 000000000000..602ce1c50d1d
>> --- /dev/null
>> +++ b/include/linux/mvebu-soc-id.h
>> @@ -0,0 +1,32 @@
>> +/*
>> + * Marvell EBU SoC ID and revision definitions.
>> + *
>> + * Copyright (C) 2014 Marvell Semiconductor
>> + *
>> + * 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 __LINUX_MVEBU_SOC_ID_H
>> +#define __LINUX_MVEBU_SOC_ID_H
>> +
>> +/* Armada XP ID */
>> +#define MV78230_DEV_ID	    0x7823
>> +#define MV78260_DEV_ID	    0x7826
>> +#define MV78460_DEV_ID	    0x7846
>> +
>> +/* Armada XP Revision */
>> +#define MV78XX0_A0_REV	    0x1
>> +#define MV78XX0_B0_REV	    0x2
>> +
>> +#ifdef CONFIG_ARCH_MVEBU
>> +int mvebu_get_soc_id(u32 *dev, u32 *rev);
>> +#else
>> +int mvebu_get_soc_id(u32 *dev, u32 *rev)
>> +{
>> +	return -1;
>> +}
>> +#endif
>> +
>> +#endif /* __LINUX_MVEBU_SOC_ID_H */
>> -- 
>> 1.8.1.2
>>

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