Hi Bo Shen,
Thank you for your review.
-----Original Message----- From: Bo Shen [mailto:voice.shen@gmail.com] Sent: 2015年10月28日 11:14 To: Yang, Wenyou Cc: U-Boot Mailing List; andreas.devel@googlemail.com Subject: Re: [PATCH v2] arm: at91: clock: Add the generated clock support
Hi Wenyou,
On 10/26/2015 11:31 AM, 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 clock source of the GCK is fixed to PLLA_CLK.
Signed-off-by: Wenyou Yang wenyou.yang@atmel.com
Hi Andreas, Bo Shen,
Thank you for your so many advices. Bo Shen, sorry for forgetting version 2 to send for your comments.
It's OK, don't worry.
At that time the datasheet is not available, now it is available now. So, add one more comment.
Please help review, thank you in advance.
Best Regards, Wenyou Yang
Changes in v2: 1./ add timeout to wait for GCK ready. 2./ add warning for timeout to wait for GCK ready. 3./ add printout when the improper GCK clock source is selected. 4./ rework AT91_PMC_PCR_GCKDIV_(x) macro to make sure x is right.
arch/arm/mach-at91/armv7/clock.c | 65
++++++++++++++++++++++++++++
arch/arm/mach-at91/include/mach/at91_pmc.h | 13 ++++++ arch/arm/mach-at91/include/mach/clk.h | 3 ++ 3 files changed, 81 insertions(+)
diff --git a/arch/arm/mach-at91/armv7/clock.c b/arch/arm/mach-at91/armv7/clock.c index 0bf453e..de95d6b 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
- 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 +174,67 @@ 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, status;
- u32 timeout = 1000;
- 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;You hard code the GCKCSS and GCKDIV. Would it be OK for all peripheral which need this kind of clock? Can you make it as a parameter?
As you know, our use-case is not complex, it is only used for one or two peripherals for now, So to make it simple, use hard-code.
Maybe we will improve it in the future, but now it is enough.
Anyway, thank you for your advice.
- writel(regval, &pmc->pcr);
- do {
udelay(1);status = readl(&pmc->sr);- } while ((!!(--timeout)) && (!(status & AT91_PMC_GCKRDY)));
- if (!timeout)
printf("Timeout waiting for GCK ready!\n"); }+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;
- 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:
printf("Improper GCK clock source selection!\n");freq = 0;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..5a51be6 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 & 0xff) << 20) +#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__ */
Best Regards, Bo Shen
Best Regards, Wenyou Yang