[DPU PATCH v2] drm/msm: make pclk_rate u64 to avoid truncation

[DPU PATCH v2] drm/msm: make pclk_rate u64 to avoid truncation

[Abhinav Kumar]

Higher values of pclk can exceed 32 bits when multiplied
by a factor.

Make the pclk_rate u64 to accommodate higher pixel clock
rates.

Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index b916f46..5a04f2d 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -668,7 +668,8 @@ static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
 	const struct msm_dsi_cfg_handler *cfg_hnd = msm_host->cfg_hnd;
 	u8 lanes = msm_host->lanes;
 	u32 bpp = dsi_get_bpp(msm_host->format);
-	u32 pclk_rate;
+	u64 pclk_rate;
+	u64 pclk_bpp;
 
 	if (!mode) {
 		pr_err("%s: mode not set\n", __func__);
@@ -676,14 +677,18 @@ static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
 	}
 
 	pclk_rate = mode->clock * 1000;
+	pclk_bpp = pclk_rate * bpp;
+
 	if (lanes > 0) {
-		msm_host->byte_clk_rate = (pclk_rate * bpp) / (8 * lanes);
+		do_div(pclk_bpp, (8 * lanes));
 	} else {
 		pr_err("%s: forcing mdss_dsi lanes to 1\n", __func__);
-		msm_host->byte_clk_rate = (pclk_rate * bpp) / 8;
+		do_div(pclk_bpp, 8);
 	}
 
-	DBG("pclk=%d, bclk=%d", pclk_rate, msm_host->byte_clk_rate);
+	msm_host->byte_clk_rate = pclk_bpp;
+
+	DBG("pclk=%llu, bclk=%d", pclk_rate, msm_host->byte_clk_rate);
 
 	msm_host->esc_clk_rate = clk_get_rate(msm_host->esc_clk);
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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Re: [DPU PATCH v2] drm/msm: make pclk_rate u64 to avoid truncation

[Sean Paul]

On Wed, May 30, 2018 at 07:12:52PM -0700, Abhinav Kumar wrote:
> Higher values of pclk can exceed 32 bits when multiplied
> by a factor.
> 
> Make the pclk_rate u64 to accommodate higher pixel clock
> rates.
> 
> Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>

Can you please rebase this on "drm/msm/dsi: adjust dsi timing for dual dsi
mode"?

Sean

> ---
>  drivers/gpu/drm/msm/dsi/dsi_host.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index b916f46..5a04f2d 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -668,7 +668,8 @@ static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
>  	const struct msm_dsi_cfg_handler *cfg_hnd = msm_host->cfg_hnd;
>  	u8 lanes = msm_host->lanes;
>  	u32 bpp = dsi_get_bpp(msm_host->format);
> -	u32 pclk_rate;
> +	u64 pclk_rate;
> +	u64 pclk_bpp;
>  
>  	if (!mode) {
>  		pr_err("%s: mode not set\n", __func__);
> @@ -676,14 +677,18 @@ static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
>  	}
>  
>  	pclk_rate = mode->clock * 1000;
> +	pclk_bpp = pclk_rate * bpp;
> +
>  	if (lanes > 0) {
> -		msm_host->byte_clk_rate = (pclk_rate * bpp) / (8 * lanes);
> +		do_div(pclk_bpp, (8 * lanes));
>  	} else {
>  		pr_err("%s: forcing mdss_dsi lanes to 1\n", __func__);
> -		msm_host->byte_clk_rate = (pclk_rate * bpp) / 8;
> +		do_div(pclk_bpp, 8);
>  	}
>  
> -	DBG("pclk=%d, bclk=%d", pclk_rate, msm_host->byte_clk_rate);
> +	msm_host->byte_clk_rate = pclk_bpp;
> +
> +	DBG("pclk=%llu, bclk=%d", pclk_rate, msm_host->byte_clk_rate);
>  
>  	msm_host->esc_clk_rate = clk_get_rate(msm_host->esc_clk);
>  
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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