Am Mittwoch, dem 31.05.2023 um 00:06 +0800 schrieb Sui Jingfeng:
> Because it is also platform-dependent, there are environments where don't
> have CLK subsystem support, for example, discreted PCI gpu. So don't rage
> quit if there is no CLK subsystem.
>
> For the GPU in LS7a1000 and LS2k2000, the working frequency of the GPU is
> tuned by configuring the PLL register directly.
>
Is this PLL under control of system firmware and invisible to Linux?
> Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 62 ++++++++++++++++++---------
> drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 1 +
> 2 files changed, 42 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> index 636d3f39ddcb..4937580551a5 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -1565,10 +1565,45 @@ static irqreturn_t irq_handler(int irq, void *data)
> return ret;
> }
>
> +static int etnaviv_gpu_clk_get(struct etnaviv_gpu *gpu)
> +{
> + struct device *dev = gpu->dev;
> +
> + if (gpu->no_clk)
> + return 0;
> +
> + gpu->clk_reg = devm_clk_get_optional(dev, "reg");
> + DBG("clk_reg: %p", gpu->clk_reg);
> + if (IS_ERR(gpu->clk_reg))
> + return PTR_ERR(gpu->clk_reg);
> +
> + gpu->clk_bus = devm_clk_get_optional(dev, "bus");
> + DBG("clk_bus: %p", gpu->clk_bus);
> + if (IS_ERR(gpu->clk_bus))
> + return PTR_ERR(gpu->clk_bus);
> +
> + gpu->clk_core = devm_clk_get(dev, "core");
> + DBG("clk_core: %p", gpu->clk_core);
> + if (IS_ERR(gpu->clk_core))
> + return PTR_ERR(gpu->clk_core);
> + gpu->base_rate_core = clk_get_rate(gpu->clk_core);
> +
> + gpu->clk_shader = devm_clk_get_optional(dev, "shader");
> + DBG("clk_shader: %p", gpu->clk_shader);
> + if (IS_ERR(gpu->clk_shader))
> + return PTR_ERR(gpu->clk_shader);
> + gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
> +
> + return 0;
> +}
> +
> static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
> {
> int ret;
>
> + if (gpu->no_clk)
> + return 0;
> +
I don't see why this would be needed? If your platform doesn't provide
CONFIG_HAVE_CLK all those functions should be successful no-ops, so
there is no need to special case this in the driver.
Or does your platform in fact provide a clk subsystem, just the GPU
clocks are managed by it?
Also all those functions are fine with being called on a NULL clk, so
shouldn't it be enough to simply avoid calling etnaviv_gpu_clk_get() in
the PCI device case?
Regards,
Lucas
> ret = clk_prepare_enable(gpu->clk_reg);
> if (ret)
> return ret;
> @@ -1599,6 +1634,9 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
>
> static int etnaviv_gpu_clk_disable(struct etnaviv_gpu *gpu)
> {
> + if (gpu->no_clk)
> + return 0;
> +
> clk_disable_unprepare(gpu->clk_shader);
> clk_disable_unprepare(gpu->clk_core);
> clk_disable_unprepare(gpu->clk_bus);
> @@ -1865,27 +1903,9 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
> return err;
>
> /* Get Clocks: */
> - gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
> - DBG("clk_reg: %p", gpu->clk_reg);
> - if (IS_ERR(gpu->clk_reg))
> - return PTR_ERR(gpu->clk_reg);
> -
> - gpu->clk_bus = devm_clk_get_optional(&pdev->dev, "bus");
> - DBG("clk_bus: %p", gpu->clk_bus);
> - if (IS_ERR(gpu->clk_bus))
> - return PTR_ERR(gpu->clk_bus);
> -
> - gpu->clk_core = devm_clk_get(&pdev->dev, "core");
> - DBG("clk_core: %p", gpu->clk_core);
> - if (IS_ERR(gpu->clk_core))
> - return PTR_ERR(gpu->clk_core);
> - gpu->base_rate_core = clk_get_rate(gpu->clk_core);
> -
> - gpu->clk_shader = devm_clk_get_optional(&pdev->dev, "shader");
> - DBG("clk_shader: %p", gpu->clk_shader);
> - if (IS_ERR(gpu->clk_shader))
> - return PTR_ERR(gpu->clk_shader);
> - gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
> + err = etnaviv_gpu_clk_get(gpu);
> + if (err)
> + return err;
>
> /* TODO: figure out max mapped size */
> dev_set_drvdata(dev, gpu);
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
> index 98c6f9c320fc..6da5209a7d64 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
> @@ -148,6 +148,7 @@ struct etnaviv_gpu {
> struct clk *clk_reg;
> struct clk *clk_core;
> struct clk *clk_shader;
> + bool no_clk;
>
> unsigned int freq_scale;
> unsigned long base_rate_core;
