diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.15/950-0860-clk-bcm-rpi-Run-some-clocks-at-the-minimum-rate-allo.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.15/950-0860-clk-bcm-rpi-Run-some-clocks-at-the-minimum-rate-allo.patch | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.15/950-0860-clk-bcm-rpi-Run-some-clocks-at-the-minimum-rate-allo.patch b/target/linux/bcm27xx/patches-5.15/950-0860-clk-bcm-rpi-Run-some-clocks-at-the-minimum-rate-allo.patch new file mode 100644 index 0000000000..cfa1349c16 --- /dev/null +++ b/target/linux/bcm27xx/patches-5.15/950-0860-clk-bcm-rpi-Run-some-clocks-at-the-minimum-rate-allo.patch @@ -0,0 +1,98 @@ +From 3bb347f520702ab886aa3513cf7d9035b09e624e Mon Sep 17 00:00:00 2001 +From: Maxime Ripard <maxime@cerno.tech> +Date: Mon, 17 Jan 2022 17:36:23 +0100 +Subject: [PATCH] clk: bcm: rpi: Run some clocks at the minimum rate + allowed + +The core clock and M2MC clocks are shared between some devices (Unicam +controllers and the HVS, and the HDMI controllers, respectively) that +will have various, varying, requirements depending on their current work +load. + +Since those loads can require a fairly high clock rate in extreme +conditions (up to ~600MHz), we can end up running those clocks at their +maximum frequency even though we no longer require such a high rate. + +Fortunately, those devices don't require an exact rate but a minimum +rate, and all the drivers are using clk_set_min_rate. Thus, we can just +rely on the fact that the clk_request minimum (which is the aggregated +minimum of all the clock users) is what we want at all times. + +Signed-off-by: Maxime Ripard <maxime@cerno.tech> +--- + drivers/clk/bcm/clk-raspberrypi.c | 37 +++++++++++++++++++++++++++++++ + 1 file changed, 37 insertions(+) + +--- a/drivers/clk/bcm/clk-raspberrypi.c ++++ b/drivers/clk/bcm/clk-raspberrypi.c +@@ -79,6 +79,7 @@ struct raspberrypi_clk_variant { + bool export; + char *clkdev; + unsigned long min_rate; ++ bool minimize; + }; + + static struct raspberrypi_clk_variant +@@ -89,6 +90,18 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NU + }, + [RPI_FIRMWARE_CORE_CLK_ID] = { + .export = true, ++ ++ /* ++ * The clock is shared between the HVS and the CSI ++ * controllers, on the BCM2711 and will change depending ++ * on the pixels composited on the HVS and the capture ++ * resolution on Unicam. ++ * ++ * Since the rate can get quite large, and we need to ++ * coordinate between both driver instances, let's ++ * always use the minimum the drivers will let us. ++ */ ++ .minimize = true, + }, + [RPI_FIRMWARE_M2MC_CLK_ID] = { + .export = true, +@@ -104,6 +117,16 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NU + * in this situation. + */ + .min_rate = 120000000, ++ ++ /* ++ * The clock is shared between the two HDMI controllers ++ * on the BCM2711 and will change depending on the ++ * resolution output on each. Since the rate can get ++ * quite large, and we need to coordinate between both ++ * driver instances, let's always use the minimum the ++ * drivers will let us. ++ */ ++ .minimize = true, + }, + [RPI_FIRMWARE_V3D_CLK_ID] = { + .export = true, +@@ -217,12 +240,26 @@ static int raspberrypi_fw_set_rate(struc + static int raspberrypi_fw_dumb_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) + { ++ struct raspberrypi_clk_data *data = ++ container_of(hw, struct raspberrypi_clk_data, hw); ++ struct raspberrypi_clk_variant *variant = data->variant; ++ + /* + * The firmware will do the rounding but that isn't part of + * the interface with the firmware, so we just do our best + * here. + */ ++ + req->rate = clamp(req->rate, req->min_rate, req->max_rate); ++ ++ /* ++ * We want to aggressively reduce the clock rate here, so let's ++ * just ignore the requested rate and return the bare minimum ++ * rate we can get away with. ++ */ ++ if (variant->minimize && req->min_rate > 0) ++ req->rate = req->min_rate; ++ + return 0; + } + |