[PATCH 05/10] arm: zynq: Move slcr initialization to separate file

From: monstr@monstr.eu (Michal Simek)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 05/10] arm: zynq: Move slcr initialization to separate file
Date: Mon, 25 Mar 2013 17:37:34 +0100	[thread overview]
Message-ID: <51507D4E.5010403@monstr.eu> (raw)
In-Reply-To: <20130325161902.GF27739@pengutronix.de>

On 03/25/2013 05:19 PM, Steffen Trumtrar wrote:
> On Mon, Mar 25, 2013 at 02:53:11PM +0100, Michal Simek wrote:
>> Create separate slcr driver instead of pollute common code.
>>
>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
>> ---
>>   arch/arm/mach-zynq/Makefile |    2 +-
>>   arch/arm/mach-zynq/common.c |   10 +------
>>   arch/arm/mach-zynq/common.h |    3 ++
>>   arch/arm/mach-zynq/slcr.c   |   69 +++++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 74 insertions(+), 10 deletions(-)
>>   create mode 100644 arch/arm/mach-zynq/slcr.c
>>
>> diff --git a/arch/arm/mach-zynq/Makefile b/arch/arm/mach-zynq/Makefile
>> index 320faed..13ee09b 100644
>> --- a/arch/arm/mach-zynq/Makefile
>> +++ b/arch/arm/mach-zynq/Makefile
>> @@ -3,4 +3,4 @@
>>   #
>>
>>   # Common support
>> -obj-y				:= common.o
>> +obj-y				:= common.o slcr.o
>> diff --git a/arch/arm/mach-zynq/common.c b/arch/arm/mach-zynq/common.c
>> index 13f9d8b..2734bd6 100644
>> --- a/arch/arm/mach-zynq/common.c
>> +++ b/arch/arm/mach-zynq/common.c
>> @@ -61,15 +61,7 @@ static void __init xilinx_init_machine(void)
>>
>>   static void __init xilinx_zynq_timer_init(void)
>>   {
>> -	struct device_node *np;
>> -	void __iomem *slcr;
>> -
>> -	np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr");
>> -	slcr = of_iomap(np, 0);
>> -	WARN_ON(!slcr);
>> -
>> -	xilinx_zynq_clocks_init(slcr);
>> -
>> +	slcr_init();
>>   	clocksource_of_init();
>>   }
>>
>> diff --git a/arch/arm/mach-zynq/common.h b/arch/arm/mach-zynq/common.h
>> index 38727a2..e30898a 100644
>> --- a/arch/arm/mach-zynq/common.h
>> +++ b/arch/arm/mach-zynq/common.h
>> @@ -17,6 +17,9 @@
>>   #ifndef __MACH_ZYNQ_COMMON_H__
>>   #define __MACH_ZYNQ_COMMON_H__
>>
>> +extern int slcr_init(void);
>> +
>> +extern void __iomem *zynq_slcr_base;
>>   extern void __iomem *scu_base;
>>
>>   #endif
>> diff --git a/arch/arm/mach-zynq/slcr.c b/arch/arm/mach-zynq/slcr.c
>> new file mode 100644
>> index 0000000..1883b70
>> --- /dev/null
>> +++ b/arch/arm/mach-zynq/slcr.c
>> @@ -0,0 +1,69 @@
>> +/*
>> + * Xilinx SLCR driver
>> + *
>> + * Copyright (c) 2011-2013 Xilinx Inc.
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * as published by the Free Software Foundation; either version
>> + * 2 of the License, or (at your option) any later version.
>> + *
>> + * You should have received a copy of the GNU General Public
>> + * License along with this program; if not, write to the Free
>> + * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
>> + * 02139, USA.
>> + */
>> +
>> +#include <linux/export.h>
>> +#include <linux/io.h>
>> +#include <linux/fs.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/slab.h>
>> +#include <linux/string.h>
>> +#include <linux/clk/zynq.h>
>> +#include "common.h"
>> +
>> +#define SLCR_UNLOCK_MAGIC		0xDF0D
>> +#define SLCR_UNLOCK			0x8   /* SCLR unlock register */
> --------------------------------------------------^ small typo
>> +
>> +void __iomem *zynq_slcr_base;
>> +
>> +/**
>> + * xslcr_init()
>> + * Returns 0 on success, negative errno otherwise.
>> + *
>> + * Called early during boot from platform code to remap SLCR area.
>> + */
>> +int __init slcr_init(void)
>> +{
>> +	struct device_node *np;
>> +
>> +	np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr");
>> +	if (!np) {
>> +		pr_err("%s: no slcr node found\n", __func__);
>> +		BUG();
>> +	}
>> +
>> +	zynq_slcr_base = of_iomap(np, 0);
>> +	if (!zynq_slcr_base) {
>> +		pr_err("%s: Unable to map I/O memory\n", __func__);
>> +		BUG();
>> +	}
>> +
>> +	/* unlock the SLCR so that registers can be changed */
>> +	writel(SLCR_UNLOCK_MAGIC, zynq_slcr_base + SLCR_UNLOCK);
>> +
>> +	pr_info("%s mapped to %p\n", np->name, zynq_slcr_base);
>> +
>> +	xilinx_zynq_clocks_init(zynq_slcr_base);
>> +
>> +	of_node_put(np);
>> +
>> +	return 0;
>> +}
>
> The slcr should definitely get it's own driver. I like that.
> But wouldn't it be better to call this in the map_io call and then, for the time
> being, assume that the slcr is unlocked and put the clocks_init-call in
> zynq_timer_init?

map_io can work with static mapping. Dynamic mapping only doesn't work in that time.
That's why it must be done later.
The reason why I call xilinx_zynq_clocks_init() from this code is
that slcr IP contains almost everything and clocks are logical subnode of this device.

Thanks,
Michal
-- 
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian