[U-Boot] [PATCH] arm: at91: clock: Add the generated clock support

[Andreas Bießmann]

Dear Wenyou Yang,

On 09.09.15 04:29, Wenyou Yang wrote:
> Some peripherals may need a second clock source that may be different
> from the system clock. This second clock is the generated clock (GCK)
> and is managed by the PMC via PMC_PCR.
> 
> For simplicity, the source of the GCK is fixed to PLLA_CLK.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
> ---
> 
>  arch/arm/mach-at91/armv7/clock.c           |   57 ++++++++++++++++++++++++++++
>  arch/arm/mach-at91/include/mach/at91_pmc.h |   13 +++++++
>  arch/arm/mach-at91/include/mach/clk.h      |    3 ++
>  3 files changed, 73 insertions(+)
> 
> diff --git a/arch/arm/mach-at91/armv7/clock.c b/arch/arm/mach-at91/armv7/clock.c
> index 0bf453e..84418a3 100644
> --- a/arch/arm/mach-at91/armv7/clock.c
> +++ b/arch/arm/mach-at91/armv7/clock.c
> @@ -5,6 +5,7 @@
>   * Copyright (C) 2005 Ivan Kokshaysky
>   * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
>   * Copyright (C) 2013 Bo Shen <voice.shen at atmel.com>
> + * Copyright (C) 2015 Wenyou Yang <wenyou.yang at atmel.com>
>   *
>   * SPDX-License-Identifier:	GPL-2.0+
>   */
> @@ -173,3 +174,59 @@ void at91_periph_clk_disable(int id)
>  
>  	writel(regval, &pmc->pcr);
>  }
> +
> +void at91_enable_periph_generated_clk(u32 id)
> +{
> +	struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
> +	u32 regval;
> +
> +	if (id > AT91_PMC_PCR_PID_MASK)
> +		return;
> +
> +	writel(id, &pmc->pcr);
> +	regval = readl(&pmc->pcr);
> +	regval &= ~AT91_PMC_PCR_GCKCSS;
> +	regval &= ~AT91_PMC_PCR_GCKDIV;
> +	regval |= AT91_PMC_PCR_GCKCSS_PLLA_CLK |
> +		  AT91_PMC_PCR_CMD_WRITE |
> +		  AT91_PMC_PCR_GCKDIV_(1) |
> +		  AT91_PMC_PCR_GCKEN;
> +
> +	writel(regval, &pmc->pcr);
> +
> +	while (!(readl(&pmc->sr) & AT91_PMC_GCKRDY))
> +		;

as I understand the other mails by Bo and you here we could have a
working system but a defective peripheral, am I right?
If so a timeout and warning would be appreciated.

> +}
> +
> +u32 at91_get_periph_generated_clk(u32 id)
> +{
> +	struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
> +	u32 regval, clk_source, div;
> +	u32 freq = 0;
> +
> +	if (id > AT91_PMC_PCR_PID_MASK)
> +		return 0;
> +
> +	writel(id, &pmc->pcr);
> +	regval = readl(&pmc->pcr);
> +
> +	clk_source = regval & AT91_PMC_PCR_GCKCSS;
> +	switch (clk_source) {
> +	case AT91_PMC_PCR_GCKCSS_SLOW_CLK:
> +		freq = CONFIG_SYS_AT91_SLOW_CLOCK;
> +		break;
> +	case AT91_PMC_PCR_GCKCSS_MAIN_CLK:
> +		freq = gd->arch.main_clk_rate_hz;
> +		break;
> +	case AT91_PMC_PCR_GCKCSS_PLLA_CLK:
> +		freq = gd->arch.plla_rate_hz;
> +		break;
> +	default:

A printout with not understood value would be good here (as Bo proposed).

> +		break;
> +	}
> +
> +	div = ((regval & AT91_PMC_PCR_GCKDIV) >> AT91_PMC_PCR_GCKDIV_OFFSET);
> +	div += 1;
> +
> +	return freq / div;
> +}
> diff --git a/arch/arm/mach-at91/include/mach/at91_pmc.h b/arch/arm/mach-at91/include/mach/at91_pmc.h
> index 8a3fb94..dcd6e36 100644
> --- a/arch/arm/mach-at91/include/mach/at91_pmc.h
> +++ b/arch/arm/mach-at91/include/mach/at91_pmc.h
> @@ -153,8 +153,20 @@ typedef struct at91_pmc {
>  #define AT91_PMC_IXR_MOSCSELS		0x00010000
>  
>  #define AT91_PMC_PCR_PID_MASK		(0x3f)
> +#define AT91_PMC_PCR_GCKCSS		(0x7 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_SLOW_CLK	(0x0 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_MAIN_CLK	(0x1 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_PLLA_CLK	(0x2 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_UPLL_CLK	(0x3 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_MCK_CLK	(0x4 << 8)
> +#define		AT91_PMC_PCR_GCKCSS_AUDIO_CLK	(0x5 << 8)
>  #define AT91_PMC_PCR_CMD_WRITE		(0x1 << 12)
> +#define AT91_PMC_PCR_DIV		(0x3 << 16)
> +#define AT91_PMC_PCR_GCKDIV		(0xff << 20)
> +#define		AT91_PMC_PCR_GCKDIV_(x)		((x) << 20)

Also here Bo's advice should be followed.

Could you please provide a v2?

Andreas

> +#define		AT91_PMC_PCR_GCKDIV_OFFSET	20
>  #define AT91_PMC_PCR_EN			(0x1 << 28)
> +#define AT91_PMC_PCR_GCKEN		(0x1 << 29)
>  
>  #define		AT91_PMC_PCK		(1 <<  0)		/* Processor Clock */
>  #define		AT91RM9200_PMC_UDP	(1 <<  1)		/* USB Devcice Port Clock [AT91RM9200 only] */
> @@ -236,6 +248,7 @@ typedef struct at91_pmc {
>  #define		AT91_PMC_PCK1RDY	(1 <<  9)		/* Programmable Clock 1 */
>  #define		AT91_PMC_PCK2RDY	(1 << 10)		/* Programmable Clock 2 */
>  #define		AT91_PMC_PCK3RDY	(1 << 11)		/* Programmable Clock 3 */
> +#define		AT91_PMC_GCKRDY		(1 << 24)
>  
>  #define		AT91_PMC_PROTKEY	0x504d4301	/* Activation Code */
>  #endif
> diff --git a/arch/arm/mach-at91/include/mach/clk.h b/arch/arm/mach-at91/include/mach/clk.h
> index 1d45e2d..dd1ed96 100644
> --- a/arch/arm/mach-at91/include/mach/clk.h
> +++ b/arch/arm/mach-at91/include/mach/clk.h
> @@ -119,4 +119,7 @@ static inline unsigned long get_pit_clk_rate(void)
>  int at91_clock_init(unsigned long main_clock);
>  void at91_periph_clk_enable(int id);
>  void at91_periph_clk_disable(int id);
> +void at91_enable_periph_generated_clk(u32 id);
> +u32 at91_get_periph_generated_clk(u32 id);
> +
>  #endif /* __ASM_ARM_ARCH_CLK_H__ */
>