[{"id":1767565,"web_url":"http://patchwork.ozlabs.org/comment/1767565/","msgid":"","list_archive_url":null,"date":"2017-09-13T04:28:02","subject":"Re: [U-Boot] [PATCH v5 4/9] ARM: at91: spl: Add mck function to\n\tlower rate while switching","submitter":{"id":6170,"url":"http://patchwork.ozlabs.org/api/people/6170/","name":"Simon Glass","email":"sjg@chromium.org"},"content":"On 12 September 2017 at 20:10, Wenyou Yang wrote:\n> Refer to the commit 70f8c8316ad(PMC: add new mck function to lower\n> rate while switching) from AT91Bootstrap.\n>\n> While switching to a lower clock source, we must switch the clock\n> source first instead of last. Otherwise, we could end up with\n> too high frequency on internal bus and peripherals.\n> This happen on SAMA5D2 as we exit from ROM code @396MHz.\n>\n> Add a function pmc_mck_init_down() to allow this sequence.\n>\n> Signed-off-by: Wenyou Yang \n> ---\n>\n> Changes in v5: None\n> Changes in v4: None\n> Changes in v3: None\n> Changes in v2: None\n>\n> arch/arm/mach-at91/armv7/clock.c | 36 +++++++++++++++++++++++++++\n> arch/arm/mach-at91/include/mach/at91_common.h | 1 +\n> 2 files changed, 37 insertions(+)\n\nReviewed-by: Simon Glass \n\n>\n> diff --git a/arch/arm/mach-at91/armv7/clock.c b/arch/arm/mach-at91/armv7/clock.c\n> index 2e55953799..8ae01f4020 100644\n> --- a/arch/arm/mach-at91/armv7/clock.c\n> +++ b/arch/arm/mach-at91/armv7/clock.c\n> @@ -150,6 +150,42 @@ void at91_mck_init(u32 mckr)\n> ;\n> }\n>\n> +void at91_mck_init_down(u32 mckr)\n> +{\n> + struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;\n> + u32 tmp;\n> +\n> + tmp = readl(&pmc->mckr);\n> + tmp &= (~AT91_PMC_MCKR_CSS_MASK);\n> + tmp |= (mckr & AT91_PMC_MCKR_CSS_MASK);\n> + writel(tmp, &pmc->mckr);\n> +\n> + while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))\n> + ;\n> +\n> +#ifdef CPU_HAS_H32MXDIV\n> + tmp = readl(&pmc->mckr);\n> + tmp &= (~AT91_PMC_MCKR_H32MXDIV);\n> + tmp |= (mckr & AT91_PMC_MCKR_H32MXDIV);\n> + writel(tmp, &pmc->mckr);\n> +#endif\n> +\n> + tmp = readl(&pmc->mckr);\n> + tmp &= (~AT91_PMC_MCKR_PLLADIV_MASK);\n> + tmp |= (mckr & AT91_PMC_MCKR_PLLADIV_MASK);\n> + writel(tmp, &pmc->mckr);\n> +\n> + tmp = readl(&pmc->mckr);\n> + tmp &= (~AT91_PMC_MCKR_MDIV_MASK);\n> + tmp |= (mckr & AT91_PMC_MCKR_MDIV_MASK);\n> + writel(tmp, &pmc->mckr);\n> +\n> + tmp = readl(&pmc->mckr);\n> + tmp &= (~AT91_PMC_MCKR_PRES_MASK);\n> + tmp |= (mckr & AT91_PMC_MCKR_PRES_MASK);\n> + writel(tmp, &pmc->mckr);\n> +}\n> +\n> int at91_enable_periph_generated_clk(u32 id, u32 clk_source, u32 div)\n> {\n> struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;\n> diff --git a/arch/arm/mach-at91/include/mach/at91_common.h b/arch/arm/mach-at91/include/mach/at91_common.h\n> index 5416eb455d..0b09ce7b2e 100644\n> --- a/arch/arm/mach-at91/include/mach/at91_common.h\n> +++ b/arch/arm/mach-at91/include/mach/at91_common.h\n> @@ -25,6 +25,7 @@ void at91_lcd_hw_init(void);\n> void at91_plla_init(u32 pllar);\n> void at91_pllb_init(u32 pllar);\n> void at91_mck_init(u32 mckr);\n> +void at91_mck_init_down(u32 mckr);\n\nFunction comment?\n\n> void at91_pmc_init(void);\n> void mem_init(void);\n> void at91_phy_reset(void);\n> --\n> 2.13.0\n>","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=lists.denx.de\n\t(client-ip=81.169.180.215; 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\n\tTue, 12 Sep 2017 21:28:22 -0700 (PDT)","MIME-Version":"1.0","In-Reply-To":"<20170913021017.9764-5-wenyou.yang@microchip.com>","References":"<20170913021017.9764-1-wenyou.yang@microchip.com>\n\t<20170913021017.9764-5-wenyou.yang@microchip.com>","From":"Simon Glass ","Date":"Tue, 12 Sep 2017 22:28:02 -0600","X-Google-Sender-Auth":"uE-JTG9ZMty8PyOpiC-bfku5HRw","Message-ID":"","To":"Wenyou Yang ","Cc":"Marek Vasut , U-Boot Mailing List , \n\tTom Rini ","Subject":"Re: [U-Boot] [PATCH v5 4/9] ARM: at91: spl: Add mck function to\n\tlower rate while switching","X-BeenThere":"u-boot@lists.denx.de","X-Mailman-Version":"2.1.18","Precedence":"list","List-Id":"U-Boot discussion ","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"base64","Errors-To":"u-boot-bounces@lists.denx.de","Sender":"\"U-Boot\" "}}]