From: "Tomoya MORINAGA" <tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public•gmane.org>
To: "Oliver Hartkopp" <socketcan-fJ+pQTUTwRTk1uMJSBkQmQ@public•gmane.org>
Cc: andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org,
Masayuki Ohtake
<masa-korg-ECg8zkTtlr0C6LszWs/t0g@public•gmane.org>,
Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public•gmane.org>,
margie.foster-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public•gmane.org,
yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org,
kok.howg.ewe-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org,
Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public•gmane.org>,
Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public•gmane.org>,
joel.clark-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
Christian Pellegrin <chripell-VaTbYqLCNhc@public•gmane.org>,
qi.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org
Subject: Re: [PATCH net-next-2.6 v2] can: Topcliff: PCH_CAN driver: Fix build warnings
Date: Tue, 9 Nov 2010 21:26:41 +0900 [thread overview]
Message-ID: <00fd01cb8009$5efc5fd0$66f8800a@maildom.okisemi.com> (raw)
In-Reply-To: 4CCAFA68.2030903@hartkopp.net
Sorry, for late response.
On Saturday, October 30, 2010 1:46 AM, Oliver Hartkopp wrote:
>
> It's just a question if the driver for an Intel Chipset should/could ignore
> the endian problematic.
>
> If this is intended the driver should only appear in Kconfig depending on X86
> or little endian systems.
This driver is for only x86 processor.
I have no intention to support processor except x86.
>
> Besides this remark, the struct pch_can_regs could also be defined in a way
> that every single CAN payload data byte could be accessed directly to allow
> e.g. this code in pch_can_rx_normal():
>
> cf->data[0] = ioread8(&priv->regs->if1_data0);
> cf->data[1] = ioread8(&priv->regs->if1_data1);
> cf->data[2] = ioread8(&priv->regs->if1_data2);
> (..)
> cf->data[6] = ioread8(&priv->regs->if1_data6);
> cf->data[7] = ioread8(&priv->regs->if1_data7);
>
> This is easy to understand and additionally endian aware.
I agree. Thease codes are very simple.
I will modify like above.
>
> In opposite to this:
>
> + if (cf->can_dlc > 2) {
> + u32 data1 = *((u16 *)&cf->data[2]);
> + iowrite32(data1, &priv->regs->if2_dataa2);
> + }
>
> Which puts a little? endian u16 into the big endian register layout.
> Sorry i'm just getting curious on this register access implementation.
I think cf->data is like below
MSB----------LSB
D3-D2-D1-D0
D7-D6-D5-D4
*((u16 *)&cf->data[2]) means "D3-D2".
This order coprresponds to register order.
data register is like below
MSB----------LSB
**-**-D3-D2
** means reserved area.
Thanks,
Tomoya MORINAGA
OKI SEMICONDUCTOR CO., LTD.
next prev parent reply other threads:[~2010-11-09 12:26 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4CCAA3D4.8070408@dsn.okisemi.com>
[not found] ` <4CCAA3D4.8070408-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-10-29 12:57 ` [PATCH net-next-2.6 v2] can: Topcliff: PCH_CAN driver: Fix build warnings Marc Kleine-Budde
[not found] ` <4CCAC4CD.7000503-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2010-10-29 16:23 ` Marc Kleine-Budde
[not found] ` <4CCAF517.2000409-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2010-10-29 19:32 ` Wolfgang Grandegger
2010-11-01 11:05 ` Marc Kleine-Budde
[not found] ` <4CCE9F0B.1000901-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2010-11-03 16:15 ` Wolfgang Grandegger
2010-11-12 11:10 ` Tomoya MORINAGA
[not found] ` <004a01cb825a$3a8bd060$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-11-12 11:45 ` Wolfgang Grandegger
2010-11-15 7:39 ` Tomoya MORINAGA
2010-11-15 8:39 ` Tomoya MORINAGA
2010-11-02 10:27 ` Tomoya MORINAGA
[not found] ` <001701cb7a78$99e1fe20$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-11-02 11:03 ` Marc Kleine-Budde
2010-11-15 8:41 ` Tomoya MORINAGA
2010-10-29 16:46 ` Oliver Hartkopp
[not found] ` <4CCAFA68.2030903-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2010-10-29 17:58 ` Marc Kleine-Budde
2010-11-09 12:26 ` Tomoya MORINAGA [this message]
[not found] ` <00fd01cb8009$5efc5fd0$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-11-09 14:47 ` Marc Kleine-Budde
2010-11-01 7:15 ` Tomoya MORINAGA
[not found] <005301cb7ffa$5b63cd90$66f8800a@maildom.okisemi.com>
2010-11-09 12:26 ` Tomoya MORINAGA
[not found] ` <00fe01cb8009$62e11410$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-11-09 12:59 ` Marc Kleine-Budde
2010-11-11 9:56 ` Tomoya MORINAGA
[not found] ` <002501cb8186$b56a6280$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-11-11 10:04 ` Marc Kleine-Budde
2010-10-29 10:37 Tomoya
[not found] <4CC61B1B.3090602@dsn.okisemi.com>
[not found] ` <4CC61B1B.3090602-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-10-26 17:52 ` David Miller
[not found] ` <20101026.105206.15244527.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2010-10-26 17:55 ` David Miller
[not found] ` <20101026.105545.200376685.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2010-10-26 18:27 ` Wolfgang Grandegger
[not found] ` <4CC71DA4.3020600-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
2010-10-26 18:52 ` Marc Kleine-Budde
2010-10-27 0:50 ` Tomoya MORINAGA
-- strict thread matches above, loose matches on Subject: below --
2010-10-26 0:04 Tomoya
2010-10-25 2:32 Tomoya
[not found] ` <4CC4EC38.2040208-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-10-25 19:14 ` David Miller
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