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

Andreas Bießmann
2015-10-23T21:00:54Z

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@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@jcrosoft.com>
> * Copyright (C) 2013 Bo Shen <voice.shen@atmel.com>
> + * Copyright (C) 2015 Wenyou Yang <wenyou.yang@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__ */
>