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Message-ID: <20110113151939.GX24920@pengutronix.de>
Date: Thu, 13 Jan 2011 16:19:39 +0100
From: Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>
To: Shawn Guo <shawn.guo@...escale.com>
Cc: davem@...emloft.net, gerg@...pgear.com, baruch@...s.co.il,
eric@...rea.com, bryan.wu@...onical.com, r64343@...escale.com,
B32542@...escale.com, lw@...o-electronics.de,
w.sang@...gutronix.de, s.hauer@...gutronix.de, jamie@...ieiles.com,
jamie@...reable.org, netdev@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 08/10] ARM: mxs: add ocotp read function
On Thu, Jan 06, 2011 at 03:13:16PM +0800, Shawn Guo wrote:
> Signed-off-by: Shawn Guo <shawn.guo@...escale.com>
> ---
> Changes for v4:
> - Call cpu_relax() during polling
>
> Changes for v2:
> - Add mutex locking for mxs_read_ocotp()
> - Use type size_t for count and i
> - Add comment for clk_enable/disable skipping
> - Add ERROR bit clearing and polling step
>
> arch/arm/mach-mxs/Makefile | 2 +-
> arch/arm/mach-mxs/include/mach/common.h | 1 +
> arch/arm/mach-mxs/ocotp.c | 79 +++++++++++++++++++++++++++++++
> 3 files changed, 81 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
is it worth to make ocotp optional? (and let evk select
CONFIG_MXS_OCOTP)
Best regards
Uwe
>
> 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..e2d39aa
> --- /dev/null
> +++ b/arch/arm/mach-mxs/ocotp.c
> @@ -0,0 +1,79 @@
> +/*
> + * 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 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);
> +
> +int mxs_read_ocotp(unsigned offset, size_t count, u32 *values)
> +{
> + void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR);
> + int timeout = 0x400;
> + size_t i;
> +
> + 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 < 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);
> +
> + mutex_unlock(&ocotp_mutex);
> +
> + return 0;
> +
> +error_unlock:
> + mutex_unlock(&ocotp_mutex);
> + pr_err("%s: timeout in reading OCOTP\n", __func__);
> + return -ETIMEDOUT;
> +}
> --
> 1.7.1
>
>
>
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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