Re: [PATCH v5 08/10] ARM: mxs: add ocotp read function

[Sascha Hauer <s.hauer@pengutronix.de>]

On Fri, Jan 14, 2011 at 03:24:54PM +0800, Shawn Guo wrote:
> Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
> ---
>  arch/arm/mach-mxs/Kconfig               |    4 ++
>  arch/arm/mach-mxs/Makefile              |    3 +
>  arch/arm/mach-mxs/include/mach/common.h |    1 +
>  arch/arm/mach-mxs/ocotp.c               |   90 +++++++++++++++++++++++++++++++
>  4 files changed, 98 insertions(+), 0 deletions(-)
>  create mode 100644 arch/arm/mach-mxs/ocotp.c
> 
> diff --git a/arch/arm/mach-mxs/Kconfig b/arch/arm/mach-mxs/Kconfig
> index 8bfc8df..cd2fbdf 100644
> --- a/arch/arm/mach-mxs/Kconfig
> +++ b/arch/arm/mach-mxs/Kconfig
> @@ -2,6 +2,9 @@ if ARCH_MXS
>  
>  source "arch/arm/mach-mxs/devices/Kconfig"
>  
> +config MXS_OCOTP
> +	bool
> +
>  config SOC_IMX23
>  	bool
>  	select CPU_ARM926T
> @@ -26,6 +29,7 @@ config MACH_MX28EVK
>  	select SOC_IMX28
>  	select MXS_HAVE_AMBA_DUART
>  	select MXS_HAVE_PLATFORM_FEC
> +	select MXS_OCOTP
>  	default y
>  	help
>  	  Include support for MX28EVK platform. This includes specific
> diff --git a/arch/arm/mach-mxs/Makefile b/arch/arm/mach-mxs/Makefile
> index 39d3f9c..623899b 100644
> --- a/arch/arm/mach-mxs/Makefile
> +++ b/arch/arm/mach-mxs/Makefile
> @@ -1,6 +1,9 @@
>  # Common support
>  obj-y := clock.o devices.o gpio.o icoll.o iomux.o system.o timer.o
>  
> +obj-$(CONFIG_PM) += pm.o
> +obj-$(CONFIG_MXS_OCOTP) += ocotp.o
> +
>  obj-$(CONFIG_SOC_IMX23) += clock-mx23.o mm-mx23.o
>  obj-$(CONFIG_SOC_IMX28) += clock-mx28.o mm-mx28.o
>  
> diff --git a/arch/arm/mach-mxs/include/mach/common.h b/arch/arm/mach-mxs/include/mach/common.h
> index 59133eb..635bb5d 100644
> --- a/arch/arm/mach-mxs/include/mach/common.h
> +++ b/arch/arm/mach-mxs/include/mach/common.h
> @@ -13,6 +13,7 @@
>  
>  struct clk;
>  
> +extern const u32 *mxs_get_ocotp(void);
>  extern int mxs_reset_block(void __iomem *);
>  extern void mxs_timer_init(struct clk *, int);
>  
> diff --git a/arch/arm/mach-mxs/ocotp.c b/arch/arm/mach-mxs/ocotp.c
> new file mode 100644
> index 0000000..eb2eab7
> --- /dev/null
> +++ b/arch/arm/mach-mxs/ocotp.c
> @@ -0,0 +1,90 @@
> +/*
> + * Copyright 2010 Freescale Semiconductor, Inc. All Rights Reserved.
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/mutex.h>
> +
> +#include <mach/mxs.h>
> +
> +#define OCOTP_WORD_OFFSET		0x20
> +#define OCOTP_WORD_COUNT		0x20
> +
> +#define BM_OCOTP_CTRL_BUSY		(1 << 8)
> +#define BM_OCOTP_CTRL_ERROR		(1 << 9)
> +#define BM_OCOTP_CTRL_RD_BANK_OPEN	(1 << 12)
> +
> +static DEFINE_MUTEX(ocotp_mutex);
> +static u32 ocotp_words[OCOTP_WORD_COUNT];
> +
> +const u32 *mxs_get_ocotp(void)
> +{
> +	void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR);
> +	int timeout = 0x400;
> +	size_t i;
> +	static int once = 0;
> +
> +	if (once)
> +		return ocotp_words;
> +
> +	mutex_lock(&ocotp_mutex);
> +
> +	/*
> +	 * clk_enable(hbus_clk) for ocotp can be skipped
> +	 * as it must be on when system is running.
> +	 */
> +
> +	/* try to clear ERROR bit */
> +	__mxs_clrl(BM_OCOTP_CTRL_ERROR, ocotp_base);
> +
> +	/* check both BUSY and ERROR cleared */
> +	while ((__raw_readl(ocotp_base) &
> +		(BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)) && --timeout)
> +		cpu_relax();
> +
> +	if (unlikely(!timeout))
> +		goto error_unlock;
> +
> +	/* open OCOTP banks for read */
> +	__mxs_setl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base);
> +
> +	/* approximately wait 32 hclk cycles */
> +	udelay(1);
> +
> +	/* poll BUSY bit becoming cleared */
> +	timeout = 0x400;
> +	while ((__raw_readl(ocotp_base) & BM_OCOTP_CTRL_BUSY) && --timeout)
> +		cpu_relax();
> +
> +	if (unlikely(!timeout))
> +		goto error_unlock;
> +
> +	for (i = 0; i < OCOTP_WORD_COUNT; i++)
> +		ocotp_words[i] = __raw_readl(ocotp_base + OCOTP_WORD_OFFSET +
> +						i * 0x10);
> +
> +	/* close banks for power saving */
> +	__mxs_clrl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base);
> +
> +	mutex_unlock(&ocotp_mutex);
> +
> +	once = 1;
> +
> +	return ocotp_words;
> +
> +error_unlock:
> +	mutex_unlock(&ocotp_mutex);
> +	pr_err("%s: timeout in reading OCOTP\n", __func__);
> +	return NULL;
> +}

EXPORT_SYMBOL?

Sascha

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