Subject: Re: [PATCH v3 1/6] clk: imx8m: Set CLK_GET_RATE_NOCACHE on dram clocks

From: Shawn Guo <[email-masked]>
Date: Mon, 2 Dec 2019 11:12:04 +0800

On Thu, Oct 31, 2019 at 11:50:22PM +0200, Leonard Crestez wrote:
> These clocks are only modified as part of DRAM frequency switches during
> which DRAM itself is briefly inaccessible. The switch is performed with
> a SMC call to by TF-A which runs from a SRAM area; upon returning to
> linux several clocks bits are modified and we need to update them.
> 
> For rate bits an easy solution is to just mark with
> CLK_GET_RATE_NOCACHE so that new rates are always read back from
> registers.
> 
> Signed-off-by: Leonard Crestez <[email-masked]>
> ---
>  drivers/clk/imx/clk-imx8mm.c | 11 +++++++++--
>  drivers/clk/imx/clk-imx8mn.c | 12 ++++++++++--
>  drivers/clk/imx/clk-imx8mq.c | 15 +++++++++++----
>  3 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
> index 030b15d7c0ce..c58f988191a5 100644
> --- a/drivers/clk/imx/clk-imx8mm.c
> +++ b/drivers/clk/imx/clk-imx8mm.c
> @@ -440,13 +440,20 @@ static int imx8mm_clocks_probe(struct platform_device *pdev)
>  
>  	/* IPG */
>  	clks[IMX8MM_CLK_IPG_ROOT] = imx_clk_divider2("ipg_root", "ahb", base + 0x9080, 0, 1);
>  	clks[IMX8MM_CLK_IPG_AUDIO_ROOT] = imx_clk_divider2("ipg_audio_root", "audio_ahb", base + 0x9180, 0, 1);
>  
> +	/*
> +	 * DRAM clocks are manipulated from TF-A outside clock framework.
> +	 * Mark with GET_RATE_NOCACHE to always read div value from hardware
> +	 */
> +	clks[IMX8MM_CLK_DRAM_ALT] = __imx8m_clk_composite("dram_alt", imx8mm_dram_alt_sels, base + 0xa000,
> +			CLK_GET_RATE_NOCACHE);
> +	clks[IMX8MM_CLK_DRAM_APB] = __imx8m_clk_composite("dram_apb", imx8mm_dram_apb_sels, base + 0xa080,
> +			CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE);
> +

I think we prefer to ignore over-80-column warnings for i.MX clock
drivers, because doing that improve the readability of code.

Shawn

>  	/* IP */
> -	clks[IMX8MM_CLK_DRAM_ALT] = imx8m_clk_composite("dram_alt", imx8mm_dram_alt_sels, base + 0xa000);
> -	clks[IMX8MM_CLK_DRAM_APB] = imx8m_clk_composite_critical("dram_apb", imx8mm_dram_apb_sels, base + 0xa080);
>  	clks[IMX8MM_CLK_VPU_G1] = imx8m_clk_composite("vpu_g1", imx8mm_vpu_g1_sels, base + 0xa100);
>  	clks[IMX8MM_CLK_VPU_G2] = imx8m_clk_composite("vpu_g2", imx8mm_vpu_g2_sels, base + 0xa180);
>  	clks[IMX8MM_CLK_DISP_DTRC] = imx8m_clk_composite("disp_dtrc", imx8mm_disp_dtrc_sels, base + 0xa200);
>  	clks[IMX8MM_CLK_DISP_DC8000] = imx8m_clk_composite("disp_dc8000", imx8mm_disp_dc8000_sels, base + 0xa280);
>  	clks[IMX8MM_CLK_PCIE1_CTRL] = imx8m_clk_composite("pcie1_ctrl", imx8mm_pcie1_ctrl_sels, base + 0xa300);
> diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
> index 9f5a5a56b45e..ca78cb1249a7 100644
> --- a/drivers/clk/imx/clk-imx8mn.c
> +++ b/drivers/clk/imx/clk-imx8mn.c
> @@ -428,12 +428,20 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
>  	clks[IMX8MN_CLK_AHB] = imx8m_clk_composite_critical("ahb", imx8mn_ahb_sels, base + 0x9000);
>  	clks[IMX8MN_CLK_AUDIO_AHB] = imx8m_clk_composite("audio_ahb", imx8mn_audio_ahb_sels, base + 0x9100);
>  	clks[IMX8MN_CLK_IPG_ROOT] = imx_clk_divider2("ipg_root", "ahb", base + 0x9080, 0, 1);
>  	clks[IMX8MN_CLK_IPG_AUDIO_ROOT] = imx_clk_divider2("ipg_audio_root", "audio_ahb", base + 0x9180, 0, 1);
>  	clks[IMX8MN_CLK_DRAM_CORE] = imx_clk_mux2_flags("dram_core_clk", base + 0x9800, 24, 1, imx8mn_dram_core_sels, ARRAY_SIZE(imx8mn_dram_core_sels), CLK_IS_CRITICAL);
> -	clks[IMX8MN_CLK_DRAM_ALT] = imx8m_clk_composite("dram_alt", imx8mn_dram_alt_sels, base + 0xa000);
> -	clks[IMX8MN_CLK_DRAM_APB] = imx8m_clk_composite_critical("dram_apb", imx8mn_dram_apb_sels, base + 0xa080);
> +
> +	/*
> +	 * DRAM clocks are manipulated from TF-A outside clock framework.
> +	 * Mark with GET_RATE_NOCACHE to always read div value from hardware
> +	 */
> +	clks[IMX8MN_CLK_DRAM_ALT] = __imx8m_clk_composite("dram_alt", imx8mn_dram_alt_sels, base + 0xa000,
> +			CLK_GET_RATE_NOCACHE);
> +	clks[IMX8MN_CLK_DRAM_APB] = __imx8m_clk_composite("dram_apb", imx8mn_dram_apb_sels, base + 0xa080,
> +			CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE);
> +
>  	clks[IMX8MN_CLK_DISP_PIXEL] = imx8m_clk_composite("disp_pixel", imx8mn_disp_pixel_sels, base + 0xa500);
>  	clks[IMX8MN_CLK_SAI2] = imx8m_clk_composite("sai2", imx8mn_sai2_sels, base + 0xa600);
>  	clks[IMX8MN_CLK_SAI3] = imx8m_clk_composite("sai3", imx8mn_sai3_sels, base + 0xa680);
>  	clks[IMX8MN_CLK_SAI5] = imx8m_clk_composite("sai5", imx8mn_sai5_sels, base + 0xa780);
>  	clks[IMX8MN_CLK_SAI6] = imx8m_clk_composite("sai6", imx8mn_sai6_sels, base + 0xa800);
> diff --git a/drivers/clk/imx/clk-imx8mq.c b/drivers/clk/imx/clk-imx8mq.c
> index 4a5dbc4366a5..ceb1e79cf2e9 100644
> --- a/drivers/clk/imx/clk-imx8mq.c
> +++ b/drivers/clk/imx/clk-imx8mq.c
> @@ -341,11 +341,12 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
>  	clks[IMX8MQ_VIDEO_PLL1_OUT] = imx_clk_gate("video_pll1_out", "video_pll1_bypass", base + 0x10, 21);
>  
>  	clks[IMX8MQ_SYS1_PLL_OUT] = imx_clk_fixed("sys1_pll_out", 800000000);
>  	clks[IMX8MQ_SYS2_PLL_OUT] = imx_clk_fixed("sys2_pll_out", 1000000000);
>  	clks[IMX8MQ_SYS3_PLL_OUT] = imx_clk_sccg_pll("sys3_pll_out", sys3_pll_out_sels, ARRAY_SIZE(sys3_pll_out_sels), 0, 0, 1, base + 0x48, CLK_IS_CRITICAL);
> -	clks[IMX8MQ_DRAM_PLL_OUT] = imx_clk_sccg_pll("dram_pll_out", dram_pll_out_sels, ARRAY_SIZE(dram_pll_out_sels), 0, 0, 0, base + 0x60, CLK_IS_CRITICAL);
> +	clks[IMX8MQ_DRAM_PLL_OUT] = imx_clk_sccg_pll("dram_pll_out", dram_pll_out_sels, ARRAY_SIZE(dram_pll_out_sels), 0, 0, 0, base + 0x60,
> +			CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE);
>  	clks[IMX8MQ_VIDEO2_PLL_OUT] = imx_clk_sccg_pll("video2_pll_out", video2_pll_out_sels, ARRAY_SIZE(video2_pll_out_sels), 0, 0, 0, base + 0x54, 0);
>  
>  	/* SYS PLL1 fixed output */
>  	clks[IMX8MQ_SYS1_PLL_40M_CG] = imx_clk_gate("sys1_pll_40m_cg", "sys1_pll_out", base + 0x30, 9);
>  	clks[IMX8MQ_SYS1_PLL_80M_CG] = imx_clk_gate("sys1_pll_80m_cg", "sys1_pll_out", base + 0x30, 11);
> @@ -433,15 +434,21 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
>  
>  	/* IPG */
>  	clks[IMX8MQ_CLK_IPG_ROOT] = imx_clk_divider2("ipg_root", "ahb", base + 0x9080, 0, 1);
>  	clks[IMX8MQ_CLK_IPG_AUDIO_ROOT] = imx_clk_divider2("ipg_audio_root", "audio_ahb", base + 0x9180, 0, 1);
>  
> -	/* IP */
> +	/*
> +	 * DRAM clocks are manipulated from TF-A outside clock framework.
> +	 * Mark with GET_RATE_NOCACHE to always read div value from hardware
> +	 */
>  	clks[IMX8MQ_CLK_DRAM_CORE] = imx_clk_mux2_flags("dram_core_clk", base + 0x9800, 24, 1, imx8mq_dram_core_sels, ARRAY_SIZE(imx8mq_dram_core_sels), CLK_IS_CRITICAL);
> +	clks[IMX8MQ_CLK_DRAM_ALT] = __imx8m_clk_composite("dram_alt", imx8mq_dram_alt_sels, base + 0xa000,
> +			CLK_GET_RATE_NOCACHE);
> +	clks[IMX8MQ_CLK_DRAM_APB] = __imx8m_clk_composite("dram_apb", imx8mq_dram_apb_sels, base + 0xa080,
> +			CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE);
>  
> -	clks[IMX8MQ_CLK_DRAM_ALT] = imx8m_clk_composite("dram_alt", imx8mq_dram_alt_sels, base + 0xa000);
> -	clks[IMX8MQ_CLK_DRAM_APB] = imx8m_clk_composite_critical("dram_apb", imx8mq_dram_apb_sels, base + 0xa080);
> +	/* IP */
>  	clks[IMX8MQ_CLK_VPU_G1] = imx8m_clk_composite("vpu_g1", imx8mq_vpu_g1_sels, base + 0xa100);
>  	clks[IMX8MQ_CLK_VPU_G2] = imx8m_clk_composite("vpu_g2", imx8mq_vpu_g2_sels, base + 0xa180);
>  	clks[IMX8MQ_CLK_DISP_DTRC] = imx8m_clk_composite("disp_dtrc", imx8mq_disp_dtrc_sels, base + 0xa200);
>  	clks[IMX8MQ_CLK_DISP_DC8000] = imx8m_clk_composite("disp_dc8000", imx8mq_disp_dc8000_sels, base + 0xa280);
>  	clks[IMX8MQ_CLK_PCIE1_CTRL] = imx8m_clk_composite("pcie1_ctrl", imx8mq_pcie1_ctrl_sels, base + 0xa300);
> -- 
> 2.17.1
> 

_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel