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    SubjectRe: [PATCH V2 1/3] lib: add support for stmp-style devices
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    HI Wolfram:

    Could you provide an API such as gpmi_reset_block()?
    It will much helpful to me.

    BR
    Huang Shijie

    On Wed, Mar 21, 2012 at 6:21 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
    > MX23/28 use IP cores which follow a register layout I have first seen on
    > STMP3xxx SoCs. In this layout, every register actually has four u32:
    >
    >  1.) to store a value directly
    >  2.) a SET register where every 1-bit sets the corresponding bit,
    >     others are unaffected
    >  3.) same with a CLR register
    >  4.) same with a TOG (toggle) register
    >
    > Also, the 2 MSBs in register 0 are always the same and can be used to reset
    > the IP core.
    >
    > All this is strictly speaking not mach-specific (but IP core specific) and,
    > thus, doesn't need to be in mach-mxs/include. At least, mx6 and mx50 also
    > utilize IP cores following this stmp-style. So:
    >
    > Introduce a stmp-style device, put the code and defines for that in a public
    > place (lib/), and let drivers for stmp-style devices select that code.
    > To avoid regressions and ease reviewing, the actual code is simply copied from
    > mach-mxs. It definately wants updates, but those need a seperate patch series.
    >
    > Voila, mach dependency gone, reusable code introduced. Note that I didn't
    > remove the duplicated code from mach-mxs yet, first the drivers have to be
    > converted.
    >
    > Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
    > Acked-by: Shawn Guo <shawn.guo@linaro.org>
    > ---
    >  include/linux/stmp_device.h |   20 +++++++++++
    >  lib/Kconfig                 |    3 ++
    >  lib/Makefile                |    2 +
    >  lib/stmp_device.c           |   80 +++++++++++++++++++++++++++++++++++++++++++
    >  4 files changed, 105 insertions(+), 0 deletions(-)
    >  create mode 100644 include/linux/stmp_device.h
    >  create mode 100644 lib/stmp_device.c
    >
    > diff --git a/include/linux/stmp_device.h b/include/linux/stmp_device.h
    > new file mode 100644
    > index 0000000..6cf7ec9
    > --- /dev/null
    > +++ b/include/linux/stmp_device.h
    > @@ -0,0 +1,20 @@
    > +/*
    > + * basic functions for devices following the "stmp" style register layout
    > + *
    > + * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
    > + *
    > + * 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.
    > + */
    > +
    > +#ifndef __STMP_DEVICE_H__
    > +#define __STMP_DEVICE_H__
    > +
    > +#define STMP_OFFSET_REG_SET    0x4
    > +#define STMP_OFFSET_REG_CLR    0x8
    > +#define STMP_OFFSET_REG_TOG    0xc
    > +
    > +extern int stmp_reset_block(void __iomem *);
    > +#endif /* __STMP_DEVICE_H__ */
    > diff --git a/lib/Kconfig b/lib/Kconfig
    > index 028aba9..d4af46f 100644
    > --- a/lib/Kconfig
    > +++ b/lib/Kconfig
    > @@ -29,6 +29,9 @@ config GENERIC_IOMAP
    >        bool
    >        select GENERIC_PCI_IOMAP
    >
    > +config STMP_DEVICE
    > +       bool
    > +
    >  config CRC_CCITT
    >        tristate "CRC-CCITT functions"
    >        help
    > diff --git a/lib/Makefile b/lib/Makefile
    > index 18515f0..f78dbcd 100644
    > --- a/lib/Makefile
    > +++ b/lib/Makefile
    > @@ -123,6 +123,8 @@ obj-$(CONFIG_SIGNATURE) += digsig.o
    >
    >  obj-$(CONFIG_CLZ_TAB) += clz_tab.o
    >
    > +obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
    > +
    >  hostprogs-y    := gen_crc32table
    >  clean-files    := crc32table.h
    >
    > diff --git a/lib/stmp_device.c b/lib/stmp_device.c
    > new file mode 100644
    > index 0000000..8ac9bcc
    > --- /dev/null
    > +++ b/lib/stmp_device.c
    > @@ -0,0 +1,80 @@
    > +/*
    > + * Copyright (C) 1999 ARM Limited
    > + * Copyright (C) 2000 Deep Blue Solutions Ltd
    > + * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
    > + * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
    > + * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
    > + * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
    > + *
    > + * 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.
    > + */
    > +
    > +#include <linux/io.h>
    > +#include <linux/errno.h>
    > +#include <linux/delay.h>
    > +#include <linux/module.h>
    > +#include <linux/stmp_device.h>
    > +
    > +#define STMP_MODULE_CLKGATE    (1 << 30)
    > +#define STMP_MODULE_SFTRST     (1 << 31)
    > +
    > +/*
    > + * Clear the bit and poll it cleared.  This is usually called with
    > + * a reset address and mask being either SFTRST(bit 31) or CLKGATE
    > + * (bit 30).
    > + */
    > +static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
    > +{
    > +       int timeout = 0x400;
    > +
    > +       writel(mask, addr + STMP_OFFSET_REG_CLR);
    > +       udelay(1);
    > +       while ((readl(addr) & mask) && --timeout)
    > +               /* nothing */;
    > +
    > +       return !timeout;
    > +}
    > +
    > +int stmp_reset_block(void __iomem *reset_addr)
    > +{
    > +       int ret;
    > +       int timeout = 0x400;
    > +
    > +       /* clear and poll SFTRST */
    > +       ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
    > +       if (unlikely(ret))
    > +               goto error;
    > +
    > +       /* clear CLKGATE */
    > +       writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
    > +
    > +       /* set SFTRST to reset the block */
    > +       writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
    > +       udelay(1);
    > +
    > +       /* poll CLKGATE becoming set */
    > +       while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
    > +               /* nothing */;
    > +       if (unlikely(!timeout))
    > +               goto error;
    > +
    > +       /* clear and poll SFTRST */
    > +       ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
    > +       if (unlikely(ret))
    > +               goto error;
    > +
    > +       /* clear and poll CLKGATE */
    > +       ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
    > +       if (unlikely(ret))
    > +               goto error;
    > +
    > +       return 0;
    > +
    > +error:
    > +       pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
    > +       return -ETIMEDOUT;
    > +}
    > +EXPORT_SYMBOL(stmp_reset_block);
    > --
    > 1.7.2.5
    >
    > --
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