From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.hauer@pengutronix.de (Sascha Hauer) Date: Tue, 6 Jul 2010 09:33:14 +0200 Subject: [PATCH] mx25: set GPT clock source to PER In-Reply-To: <20100706063511.GB28547@jasper.tkos.co.il> References: <20100704084343.GB19559@jasper.tkos.co.il> <40bc9462f125233cc9c63631a9b987ed684b6d97.1278233166.git.baruch@tkos.co.il> <20100705082123.GD26079@pengutronix.de> <20100706063511.GB28547@jasper.tkos.co.il> Message-ID: <20100706073314.GJ26079@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Jul 06, 2010 at 09:35:11AM +0300, Baruch Siach wrote: > Hi Sascha, > > On Mon, Jul 05, 2010 at 10:21:23AM +0200, Sascha Hauer wrote: > > On Sun, Jul 04, 2010 at 11:47:29AM +0300, Baruch Siach wrote: > > > This fixes time accounting on mx25 base systems. > > > > > > Signed-off-by: Baruch Siach > > > --- > > > arch/arm/plat-mxc/time.c | 3 ++- > > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > > > diff --git a/arch/arm/plat-mxc/time.c b/arch/arm/plat-mxc/time.c > > > index f9a1b05..0d7e0f9 100644 > > > --- a/arch/arm/plat-mxc/time.c > > > +++ b/arch/arm/plat-mxc/time.c > > > @@ -56,6 +56,7 @@ > > > /* MX31, MX35, MX25, MXC91231, MX5 */ > > > #define V2_TCTL_WAITEN (1 << 3) /* Wait enable mode */ > > > #define V2_TCTL_CLK_IPG (1 << 6) > > > +#define V2_TCTL_CLK_PER (2 << 6) > > > #define V2_TCTL_FRR (1 << 9) > > > #define V2_IR 0x0c > > > #define V2_TSTAT 0x08 > > > @@ -308,7 +309,7 @@ void __init mxc_timer_init(struct clk *timer_clk, void __iomem *base, int irq) > > > __raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */ > > > > > > if (timer_is_v2()) > > > - tctl_val = V2_TCTL_CLK_IPG | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN; > > > + tctl_val = V2_TCTL_CLK_PER | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN; > > > else > > > tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN; > > > > > > > I wonder why I applied > > > > commit faed40665d2d81b7e0e537d14ef680ab3da9f22d > > Author: Baruch Siach > > Date: Mon Jan 25 12:58:21 2010 +0200 > > > > mx25: fix time accounting > > > > The gpt_clk rate function doesn't consider the PER divider. This causes a > > significant drift in time accounting. Fix this by introducing the correct rate > > calculation function. > > > > Signed-off-by: Baruch Siach > > Signed-off-by: Sascha Hauer > > > > diff --git a/arch/arm/mach-mx25/clock.c b/arch/arm/mach-mx25/clock.c > > index 08aaa38..c003ac4 100644 > > --- a/arch/arm/mach-mx25/clock.c > > +++ b/arch/arm/mach-mx25/clock.c > > @@ -119,6 +119,11 @@ static unsigned long get_rate_nfc(struct clk *clk) > > return get_rate_per(8); > > } > > > > +static unsigned long get_rate_gpt(struct clk *clk) > > +{ > > + return get_rate_per(5); > > +} > > + > > static unsigned long get_rate_otg(struct clk *clk) > > { > > return 48000000; /* FIXME */ > > @@ -156,7 +161,7 @@ static void clk_cgcr_disable(struct clk *clk) > > .secondary = s, \ > > } > > > > -DEFINE_CLOCK(gpt_clk, 0, CCM_CGCR0, 5, get_rate_ipg, NULL, NULL); > > +DEFINE_CLOCK(gpt_clk, 0, CCM_CGCR0, 5, get_rate_gpt, NULL, NULL); > > DEFINE_CLOCK(uart_per_clk, 0, CCM_CGCR0, 15, get_rate_uart, NULL, NULL); > > DEFINE_CLOCK(cspi1_clk, 0, CCM_CGCR1, 5, get_rate_ipg, NULL, NULL); > > DEFINE_CLOCK(cspi2_clk, 0, CCM_CGCR1, 6, get_rate_ipg, NULL, NULL); > > > > This changed the gpt clock from ipg to the peripheral clock and I > > explained why this is wrong. Now of course we now must use the > > peripheral clock in the timer code. > > > > Does it work when you revert faed40665d2d81b7e0e537d14ef680ab3da9f22d? > > Reverting faed406 works on our target board, but breaks the i.MX25 PDK. > > > In any case, we can't apply your patch because it would break other v2 > > based architectures like i.MX35. > > What do you suggest then? Tell the timer code which clock to use with an argument to mxc_timer_init() and add the missing clocks to the clock.c file. You also have to pass this argument through from the board to mx25_clocks_init(). That's a lot of work and in the end we still do not know why some i.MX25 variants need the peripheral clock and others need the ipg clock. So what I really suggest is that you invest some research to find the source of this strangeness. Some things that could help you are: - the clko pin - Do both boards have identical i.MX25 tapeout versions? - Are the clocks initialized identically? I bricked my i.MX25 PDK so unfortunately I do not have any hardware to do some tests myself. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |