[PATCH] RFC: U300 clock updates to match PrimeCell clocking

[PATCH] RFC: U300 clock updates to match PrimeCell clocking

[Rabin Vincent]

(corrected lakml address)

On Wed, Jul 14, 2010 at 02:03:27AM +0200, Linus Walleij wrote:
> This makes the U300 architecture use the PrimeCell (AMBA) bus
> clocking method suggested by Russell King. Since the bus will
> now clock itself, we can remove the special PrimeCell clocking
> hooks in the clock file.

In order to be able to remove your clock enabling around the
amba_device_register() calls, the busclk get/enabling would need to be
also added around the peripheral ID read in amba_device_register(), not
just before the probe call, where Russell's patch added it.

Rabin

> ---
>  arch/arm/mach-u300/clock.c |   56 +++++++++++---------------------------------
>  arch/arm/mach-u300/clock.h |    2 -
>  arch/arm/mach-u300/core.c  |    2 -
>  3 files changed, 14 insertions(+), 46 deletions(-)
> 
> diff --git a/arch/arm/mach-u300/clock.c b/arch/arm/mach-u300/clock.c
> index 5af71d5..5c7c90e 100644
> --- a/arch/arm/mach-u300/clock.c
> +++ b/arch/arm/mach-u300/clock.c
> @@ -1218,6 +1218,13 @@ static struct clk ppm_clk = {
>  	.clk = clkref,				\
>  	}
>  
> +#define DEF_LOOKUP_PRECISE(devid, conid, clkref) \
> +	{					\
> +	.dev_id = devid,			\
> +	.con_id = conid,			\
> +	.clk = clkref,				\
> +	}
> +
>  /*
>   * Here we only define clocks that are meaningful to
>   * look up through clockdevice.
> @@ -1240,12 +1247,14 @@ static struct clk_lookup lookups[] = {
>  	DEF_LOOKUP("ahb",       &ahb_clk),
>  	/* AHB bridge clocks */
>  	DEF_LOOKUP("ahb_subsys", &ahb_subsys_clk),
> -	DEF_LOOKUP("intcon",    &intcon_clk),
> +	DEF_LOOKUP_PRECISE("intcon", "ahb_pclk", &intcon_clk),
>  	DEF_LOOKUP("mspro",     &mspro_clk),
> -	DEF_LOOKUP("pl172",     &emif_clk),
> +	DEF_LOOKUP_PRECISE("mspro", "ahb_pclk", &mspro_clk),
> +	DEF_LOOKUP_PRECISE("pl172", "ahb_pclk", &emif_clk),
>  	/* FAST bridge clocks */
>  	DEF_LOOKUP("fast",      &fast_clk),
>  	DEF_LOOKUP("mmci",      &mmcsd_clk),
> +	DEF_LOOKUP_PRECISE("mmci", "ahb_pclk", &mmcsd_clk),
>  	/*
>  	 * The .0 and .1 identifiers on these comes from the platform device
>  	 * .id field and are assigned when the platform devices are registered.
> @@ -1255,13 +1264,16 @@ static struct clk_lookup lookups[] = {
>  	DEF_LOOKUP("stu300.0",  &i2c0_clk),
>  	DEF_LOOKUP("stu300.1",  &i2c1_clk),
>  	DEF_LOOKUP("pl022",     &spi_clk),
> +	DEF_LOOKUP_PRECISE("pl022", "ahb_pclk", &spi_clk),
>  #ifdef CONFIG_MACH_U300_BS335
>  	DEF_LOOKUP("uart1",     &uart1_clk),
> +	DEF_LOOKUP_PRECISE("uart1", "ahb_pclk", &uart1_clk),
>  #endif
>  	/* SLOW bridge clocks */
>  	DEF_LOOKUP("slow",      &slow_clk),
>  	DEF_LOOKUP("coh901327_wdog",      &wdog_clk),
>  	DEF_LOOKUP("uart0",     &uart_clk),
> +	DEF_LOOKUP_PRECISE("uart0", "ahb_pclk", &uart_clk),
>  	DEF_LOOKUP("apptimer",  &app_timer_clk),
>  	DEF_LOOKUP("coh901461-keypad",    &keypad_clk),
>  	DEF_LOOKUP("u300-gpio", &gpio_clk),
> @@ -1281,46 +1293,6 @@ static void __init clk_register(void)
>  }
>  
>  /*
> - * These are the clocks for cells registered as primecell drivers
> - * on the AMBA bus. These must be on during AMBA device registration
> - * since the bus probe will attempt to read magic configuration
> - * registers for these devices. If they are deactivated these probes
> - * will fail.
> - *
> - *
> - * Please note that on emif, both RAM and NAND is connected in dual
> - * RAM phones. On single RAM phones, ram is on semi and NAND on emif.
> - *
> - */
> -void u300_clock_primecells(void)
> -{
> -	clk_enable(&intcon_clk);
> -	clk_enable(&uart_clk);
> -#ifdef CONFIG_MACH_U300_BS335
> -	clk_enable(&uart1_clk);
> -#endif
> -	clk_enable(&spi_clk);
> -
> -	clk_enable(&mmcsd_clk);
> -
> -}
> -EXPORT_SYMBOL(u300_clock_primecells);
> -
> -void u300_unclock_primecells(void)
> -{
> -
> -	clk_disable(&intcon_clk);
> -	clk_disable(&uart_clk);
> -#ifdef CONFIG_MACH_U300_BS335
> -	clk_disable(&uart1_clk);
> -#endif
> -	clk_disable(&spi_clk);
> -	clk_disable(&mmcsd_clk);
> -
> -}
> -EXPORT_SYMBOL(u300_unclock_primecells);
> -
> -/*
>   * The interrupt controller is enabled before the clock API is registered.
>   */
>  void u300_enable_intcon_clock(void)
> diff --git a/arch/arm/mach-u300/clock.h b/arch/arm/mach-u300/clock.h
> index fc6d9cc..e5e096b 100644
> --- a/arch/arm/mach-u300/clock.h
> +++ b/arch/arm/mach-u300/clock.h
> @@ -45,8 +45,6 @@ struct clk {
>  	void (*disable) (struct clk *);
>  };
>  
> -void u300_clock_primecells(void);
> -void u300_unclock_primecells(void);
>  void u300_enable_intcon_clock(void);
>  void u300_enable_timer_clock(void);
>  
> diff --git a/arch/arm/mach-u300/core.c b/arch/arm/mach-u300/core.c
> index 5f34eb6..98e4639 100644
> --- a/arch/arm/mach-u300/core.c
> +++ b/arch/arm/mach-u300/core.c
> @@ -1642,12 +1642,10 @@ void __init u300_init_devices(void)
>  	u300_spi_init(&pl022_device);
>  
>  	/* Register the AMBA devices in the AMBA bus abstraction layer */
> -	u300_clock_primecells();
>  	for (i = 0; i < ARRAY_SIZE(amba_devs); i++) {
>  		struct amba_device *d = amba_devs[i];
>  		amba_device_register(d, &iomem_resource);
>  	}
> -	u300_unclock_primecells();
>  
>  	u300_assign_physmem();
>  
> -- 
> 1.7.1
> 

[PATCH] RFC: U300 clock updates to match PrimeCell clocking

[Russell King - ARM Linux]

On Thu, Jul 15, 2010 at 12:33:11AM +0530, Rabin Vincent wrote:
> (corrected lakml address)
> 
> On Wed, Jul 14, 2010 at 02:03:27AM +0200, Linus Walleij wrote:
> > This makes the U300 architecture use the PrimeCell (AMBA) bus
> > clocking method suggested by Russell King. Since the bus will
> > now clock itself, we can remove the special PrimeCell clocking
> > hooks in the clock file.
> 
> In order to be able to remove your clock enabling around the
> amba_device_register() calls, the busclk get/enabling would need to be
> also added around the peripheral ID read in amba_device_register(), not
> just before the probe call, where Russell's patch added it.

Ok, let's do that too.

[PATCH] RFC: U300 clock updates to match PrimeCell clocking

[Linus Walleij]

2010/7/14 Rabin Vincent <rabin@rab.in>:

> In order to be able to remove your clock enabling around the
> amba_device_register() calls, the busclk get/enabling would need to be
> also added around the peripheral ID read in amba_device_register(), not
> just before the probe call, where Russell's patch added it.

Of course. You see everything...
Russell seems to be onto it.

Rabin do you have a rough enough idea of how the ahb_pclock and
e.g. SSPCLK are routed to different PRCMU things in the U8500?
IIRC what we have registered there right now are actually mostly
the correct SSPCLK etc for external clocking, but we might want to
add the ahb_pclk references as well.

Yours,
Linus Walleij