20ea6adbf1
Build system: x86_64 Build-tested: bcm2708, bcm2709, bcm2710, bcm2711 Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B Signed-off-by: Marty Jones <mj8263788@gmail.com> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
70 lines
2.0 KiB
Diff
70 lines
2.0 KiB
Diff
From ac0b202c0bae166810c63e2ac5067b6ea3f4af43 Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime@cerno.tech>
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Date: Mon, 17 Jan 2022 17:31:06 +0100
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Subject: [PATCH] clk: bcm: rpi: Set a default minimum rate
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The M2MC clock provides the state machine clock for both HDMI
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controllers.
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However, if no HDMI monitor is plugged in at boot, its clock rate will
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be left at 0 by the firmware and will make any register access end up in
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a CPU stall, even though the clock was enabled.
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We had some code in the HDMI controller to deal with this before, but it
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makes more sense to have it in the clock driver. Move it there.
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Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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---
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drivers/clk/bcm/clk-raspberrypi.c | 26 ++++++++++++++++++++++++++
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1 file changed, 26 insertions(+)
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--- a/drivers/clk/bcm/clk-raspberrypi.c
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+++ b/drivers/clk/bcm/clk-raspberrypi.c
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@@ -78,6 +78,7 @@ struct raspberrypi_clk_data {
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struct raspberrypi_clk_variant {
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bool export;
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char *clkdev;
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+ unsigned long min_rate;
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};
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static struct raspberrypi_clk_variant
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@@ -91,6 +92,18 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NU
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},
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[RPI_FIRMWARE_M2MC_CLK_ID] = {
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.export = true,
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+
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+ /*
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+ * If we boot without any cable connected to any of the
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+ * HDMI connector, the firmware will skip the HSM
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+ * initialization and leave it with a rate of 0,
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+ * resulting in a bus lockup when we're accessing the
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+ * registers even if it's enabled.
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+ *
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+ * Let's put a sensible default so that we don't end up
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+ * in this situation.
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+ */
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+ .min_rate = 120000000,
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},
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[RPI_FIRMWARE_V3D_CLK_ID] = {
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.export = true,
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@@ -278,6 +291,19 @@ static struct clk_hw *raspberrypi_clk_re
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}
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}
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+ if (variant->min_rate) {
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+ unsigned long rate;
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+
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+ clk_hw_set_rate_range(&data->hw, variant->min_rate, max_rate);
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+
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+ rate = raspberrypi_fw_get_rate(&data->hw, 0);
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+ if (rate < variant->min_rate) {
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+ ret = raspberrypi_fw_set_rate(&data->hw, variant->min_rate, 0);
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+ if (ret)
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+ return ERR_PTR(ret);
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+ }
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+ }
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+
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return &data->hw;
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}
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