From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Subject: Re: [PATCH 2/2] rtc: driver for Conexant Digicolor CX92755 on-chip RTC Date: Tue, 24 Mar 2015 07:31:24 +0200 Message-ID: <20150324053124.GN2825@tarshish> References: <374ef109005ed14c3a0052a9da5226b87f8dc215.1427117334.git.baruch@tkos.co.il> <20150323153334.a373431dd5af6b669f716d83@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20150323153334.a373431dd5af6b669f716d83-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Andrew Morton Cc: Alessandro Zummo , rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Andrew, On Mon, Mar 23, 2015 at 03:33:34PM -0700, Andrew Morton wrote: > On Mon, 23 Mar 2015 15:28:54 +0200 Baruch Siach wrote: > > Add driver for the RTC hardware block on the Conexant CX92755 SoC, from > > the > > Digicolor series of SoCs. Tested on the Equinox evaluation board for the > > CX92755 chip. > > > > ... > > > > +static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) > > +{ > > + u8 read_cmds[] = {CMD_READ, CMD_NOP}; > > + u32 reference, time1, time2; > > + int ret; > > + > > + ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds)); > > This is asking the compiler to build read_cmds[] on the stack each time > dc_rtc_read() is called. > > If we instead create the array at compile time: > > +++ a/drivers/rtc/rtc-digicolor.c > @@ -42,7 +42,7 @@ struct dc_rtc { > void __iomem *regs; > }; > > -static int dc_rtc_cmds(struct dc_rtc *rtc, u8 *cmds, int len) > +static int dc_rtc_cmds(struct dc_rtc *rtc, const u8 *cmds, int len) > { > u8 val; > int i, ret; > @@ -62,7 +62,7 @@ static int dc_rtc_cmds(struct dc_rtc *rt > > static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) > { > - u8 read_cmds[] = {CMD_READ, CMD_NOP}; > + static const u8 read_cmds[] = {CMD_READ, CMD_NOP}; > u32 reference, time1, time2; > int ret; > > @@ -86,7 +86,7 @@ static int dc_rtc_read(struct dc_rtc *rt > > static int dc_rtc_write(struct dc_rtc *rtc, u32 val) > { > - u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; > + static const u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; > > writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE); > return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds)); > > The code gets a bit smaller and faster: > > text data bss dec hex filename > 1628 400 512 2540 9ec drivers/rtc/rtc-digicolor.o-before > 1593 400 536 2529 9e1 drivers/rtc/rtc-digicolor.o-after Thanks for the tip, and for taking the driver through your tree. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch-NswTu9S1W3P6gbPvEgmw2w@public.gmane.org - tel: +972.2.679.5364, http://www.tkos.co.il - -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: baruch@tkos.co.il (Baruch Siach) Date: Tue, 24 Mar 2015 07:31:24 +0200 Subject: [PATCH 2/2] rtc: driver for Conexant Digicolor CX92755 on-chip RTC In-Reply-To: <20150323153334.a373431dd5af6b669f716d83@linux-foundation.org> References: <374ef109005ed14c3a0052a9da5226b87f8dc215.1427117334.git.baruch@tkos.co.il> <20150323153334.a373431dd5af6b669f716d83@linux-foundation.org> Message-ID: <20150324053124.GN2825@tarshish> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Andrew, On Mon, Mar 23, 2015 at 03:33:34PM -0700, Andrew Morton wrote: > On Mon, 23 Mar 2015 15:28:54 +0200 Baruch Siach wrote: > > Add driver for the RTC hardware block on the Conexant CX92755 SoC, from > > the > > Digicolor series of SoCs. Tested on the Equinox evaluation board for the > > CX92755 chip. > > > > ... > > > > +static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) > > +{ > > + u8 read_cmds[] = {CMD_READ, CMD_NOP}; > > + u32 reference, time1, time2; > > + int ret; > > + > > + ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds)); > > This is asking the compiler to build read_cmds[] on the stack each time > dc_rtc_read() is called. > > If we instead create the array at compile time: > > +++ a/drivers/rtc/rtc-digicolor.c > @@ -42,7 +42,7 @@ struct dc_rtc { > void __iomem *regs; > }; > > -static int dc_rtc_cmds(struct dc_rtc *rtc, u8 *cmds, int len) > +static int dc_rtc_cmds(struct dc_rtc *rtc, const u8 *cmds, int len) > { > u8 val; > int i, ret; > @@ -62,7 +62,7 @@ static int dc_rtc_cmds(struct dc_rtc *rt > > static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) > { > - u8 read_cmds[] = {CMD_READ, CMD_NOP}; > + static const u8 read_cmds[] = {CMD_READ, CMD_NOP}; > u32 reference, time1, time2; > int ret; > > @@ -86,7 +86,7 @@ static int dc_rtc_read(struct dc_rtc *rt > > static int dc_rtc_write(struct dc_rtc *rtc, u32 val) > { > - u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; > + static const u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; > > writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE); > return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds)); > > The code gets a bit smaller and faster: > > text data bss dec hex filename > 1628 400 512 2540 9ec drivers/rtc/rtc-digicolor.o-before > 1593 400 536 2529 9e1 drivers/rtc/rtc-digicolor.o-after Thanks for the tip, and for taking the driver through your tree. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -