From: w.sang@pengutronix.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] ARM: mxs: detect SoC by checking CHIPID register
Date: Fri, 6 Jan 2012 12:40:29 +0100 [thread overview]
Message-ID: <20120106114029.GB2610@pengutronix.de> (raw)
In-Reply-To: <1325817712-4573-2-git-send-email-shawn.guo@linaro.org>
On Fri, Jan 06, 2012 at 10:41:51AM +0800, Shawn Guo wrote:
> Both imx23 and imx28 have CHIPID register at address 0x8001c310, which
> can be used to identify the SoC. This patch changes cpu_is_xxx and
> __arch_decomp_setup to use this CHIPID register than machine type to
> detect the chip between imx23 and imx28, so that we do not need to
> change these functions whenever a new board/machine gets added.
>
> Suggested-by: Wolfram Sang <w.sang@pengutronix.de>
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
[...]
> +
> +/*
> + * MXS CPU types
> + */
> +#define CHIPID (MXS_IO_ADDRESS(MXS_DIGCTL_BASE_ADDR) + 0x310)
Hmm, in general I don't like accessing single registers this way. Since
we only read, it might work for now, but I think it will turn ugly the
more we use from DIGCTL (which is annoying to abstract, yes).
0x310 should not be hardcoded. CHIPID could be MXS_CHIPID.
> diff --git a/arch/arm/mach-mxs/include/mach/uncompress.h b/arch/arm/mach-mxs/include/mach/uncompress.h
> index 6777674..a8de26d 100644
> --- a/arch/arm/mach-mxs/include/mach/uncompress.h
> +++ b/arch/arm/mach-mxs/include/mach/uncompress.h
> @@ -55,16 +55,17 @@ static inline void flush(void)
>
> #define MX23_DUART_BASE_ADDR 0x80070000
> #define MX28_DUART_BASE_ADDR 0x80074000
> +#define MXS_DIGCTL_CHIPID 0x8001c310
>
> static inline void __arch_decomp_setup(unsigned long arch_id)
> {
> - switch (arch_id) {
> - case MACH_TYPE_MX23EVK:
> + u16 chipid = (*(volatile unsigned long *) MXS_DIGCTL_CHIPID) >> 16;
Can't we use the cpu_is-functions here?
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2012-01-06 11:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-06 2:41 [PATCH 0/2] ARM: mxs: use CHIPID hardware to detect SoC Shawn Guo
2012-01-06 2:41 ` [PATCH 1/2] ARM: mxs: detect SoC by checking CHIPID register Shawn Guo
2012-01-06 11:40 ` Wolfram Sang [this message]
2012-01-06 13:39 ` Shawn Guo
2012-01-06 13:43 ` Wolfram Sang
2012-01-06 2:41 ` [PATCH 2/2] ARM: mxs: Add initial support for Bluegiga APX4 Development Kit Shawn Guo
2012-01-06 11:26 ` [PATCH 0/2] ARM: mxs: use CHIPID hardware to detect SoC Lauri Hintsala
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