78 lines
2.6 KiB
Diff
78 lines
2.6 KiB
Diff
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From 71ba043e5c5575f3d86536acade70dab6599489b Mon Sep 17 00:00:00 2001
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From: Vincent Fazio <vfazio@xes-inc.com>
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Date: Mon, 13 Sep 2021 11:22:30 -0500
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Subject: [PATCH] arm: rpi: fallback to max clock rate for MMC clock
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In rpi-firmware 25e2b597ebfb2495eab4816a276758dcc6ea21f1 and later,
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the GET_CLOCK_RATE mailbox property was changed to return the last
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value set by SET_CLOCK_RATE.
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https://github.com/raspberrypi/firmware/issues/1619#issuecomment-917025502
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U-Boot does not call SET_CLOCK_RATE so bcm2835_get_mmc_clock will
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return zero and can cause degraded MMC performance.
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Calling SET_CLOCK_RATE fixes the frequency of the clock to a specific
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value and disables the firmware's clock scaling so is not an option.
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Instead, fallback to GET_MAX_CLOCK_RATE in bcm2835_get_mmc_clock if
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GET_CLOCK_RATE returns zero.
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Signed-off-by: Vincent Fazio <vfazio@xes-inc.com>
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---
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arch/arm/mach-bcm283x/include/mach/mbox.h | 2 ++
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arch/arm/mach-bcm283x/msg.c | 20 +++++++++++++++++++-
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2 files changed, 21 insertions(+), 1 deletion(-)
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diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
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index 2ae2d3d97c3..7dcac583cc4 100644
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--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
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+++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
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@@ -224,6 +224,8 @@ struct bcm2835_mbox_tag_set_power_state {
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};
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#define BCM2835_MBOX_TAG_GET_CLOCK_RATE 0x00030002
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+#define BCM2835_MBOX_TAG_GET_MAX_CLOCK_RATE 0x00030004
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+#define BCM2835_MBOX_TAG_GET_MIN_CLOCK_RATE 0x00030007
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#define BCM2835_MBOX_CLOCK_ID_EMMC 1
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#define BCM2835_MBOX_CLOCK_ID_UART 2
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diff --git a/arch/arm/mach-bcm283x/msg.c b/arch/arm/mach-bcm283x/msg.c
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index 347aece3cd8..e2badfecb09 100644
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--- a/arch/arm/mach-bcm283x/msg.c
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+++ b/arch/arm/mach-bcm283x/msg.c
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@@ -75,6 +75,7 @@ int bcm2835_get_mmc_clock(u32 clock_id)
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{
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ALLOC_CACHE_ALIGN_BUFFER(struct msg_get_clock_rate, msg_clk, 1);
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int ret;
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+ u32 clock_rate = 0;
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ret = bcm2835_power_on_module(BCM2835_MBOX_POWER_DEVID_SDHCI);
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if (ret)
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@@ -90,7 +91,24 @@ int bcm2835_get_mmc_clock(u32 clock_id)
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return -EIO;
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}
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- return msg_clk->get_clock_rate.body.resp.rate_hz;
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+ clock_rate = msg_clk->get_clock_rate.body.resp.rate_hz;
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+
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+ if (clock_rate == 0)
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+ {
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+ BCM2835_MBOX_INIT_HDR(msg_clk);
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+ BCM2835_MBOX_INIT_TAG(&msg_clk->get_clock_rate, GET_MAX_CLOCK_RATE);
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+ msg_clk->get_clock_rate.body.req.clock_id = clock_id;
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+
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+ ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &msg_clk->hdr);
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+ if (ret) {
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+ printf("bcm2835: Could not query max eMMC clock rate\n");
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+ return -EIO;
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+ }
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+
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+ clock_rate = msg_clk->get_clock_rate.body.resp.rate_hz;
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+ }
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+
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+ return clock_rate;
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}
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int bcm2835_get_video_size(int *widthp, int *heightp)
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