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

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

Hello Shawn,

On Tue, Dec 28, 2010 at 10:55:53PM +0800, Shawn Guo wrote:
> Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
> ---
>  arch/arm/mach-mxs/Makefile              |    2 +-
>  arch/arm/mach-mxs/include/mach/common.h |    1 +
>  arch/arm/mach-mxs/ocotp.c               |   52 +++++++++++++++++++++++++++++++
>  3 files changed, 54 insertions(+), 1 deletions(-)
>  create mode 100644 arch/arm/mach-mxs/ocotp.c
> 
> diff --git a/arch/arm/mach-mxs/Makefile b/arch/arm/mach-mxs/Makefile
> index 39d3f9c..f23ebbd 100644
> --- a/arch/arm/mach-mxs/Makefile
> +++ b/arch/arm/mach-mxs/Makefile
> @@ -1,5 +1,5 @@
>  # Common support
> -obj-y := clock.o devices.o gpio.o icoll.o iomux.o system.o timer.o
> +obj-y := clock.o devices.o gpio.o icoll.o iomux.o ocotp.o system.o timer.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..cf02552 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 int mxs_read_ocotp(int offset, int count, u32 *values);
>  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..24457d7
> --- /dev/null
> +++ b/arch/arm/mach-mxs/ocotp.c
> @@ -0,0 +1,52 @@
> +/*
> + * 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 <mach/mxs.h>
> +
> +#define BM_OCOTP_CTRL_RD_BANK_OPEN	(1 << 12)
> +#define BM_OCOTP_CTRL_BUSY		(1 << 8)
> +
> +int mxs_read_ocotp(int offset, int count, u32 *values)
Maybe use size_t as type for count?  unsigned for offset?

> +{
> +	void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR);
> +	int i, timeout = 0x400;
> +
> +	/* 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 */
> +	while ((__raw_readl(ocotp_base) & BM_OCOTP_CTRL_BUSY) && --timeout)
> +		/* nothing */;
> +
> +	if (unlikely(!timeout))
> +		goto error;
> +
> +	for (i = 0; i < count; i++, offset += 4)
> +		*values++ = __raw_readl(ocotp_base + offset);
> +
> +	/* close banks for power saving */
> +	__mxs_clrl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base);
> +
> +	return 0;
> +
> +error:
> +	pr_err("%s: timeout in reading OCOTP\n", __func__);
> +	return -ETIMEDOUT;
> +}
does this need locking?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |