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62b7f5931c
bcm2708: boot tested on RPi B+ v1.2
bcm2709: boot tested on RPi 3B v1.2 and RPi 4B v1.1 4G
bcm2710: boot tested on RPi 3B v1.2
bcm2711: boot tested on RPi 4B v1.1 4G
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
(cherry-picked from commit f07e572f64)
106 lines
3.9 KiB
Diff
106 lines
3.9 KiB
Diff
From 4ae861da5eaf53e5b4303f080bff0e34e22da0d9 Mon Sep 17 00:00:00 2001
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From: Lukas Wunner <lukas@wunner.de>
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Date: Tue, 4 Feb 2020 15:50:41 +0100
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Subject: [PATCH] irqchip/bcm2835: Quiesce IRQs left enabled by
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bootloader
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[ Upstream commit bd59b343a9c902c522f006e6d71080f4893bbf42 ]
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Per the spec, the BCM2835's IRQs are all disabled when coming out of
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power-on reset. Its IRQ driver assumes that's still the case when the
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kernel boots and does not perform any initialization of the registers.
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However the Raspberry Pi Foundation's bootloader leaves the USB
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interrupt enabled when handing over control to the kernel.
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Quiesce IRQs and the FIQ if they were left enabled and log a message to
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let users know that they should update the bootloader once a fixed
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version is released.
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If the USB interrupt is not quiesced and the USB driver later on claims
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the FIQ (as it does on the Raspberry Pi Foundation's downstream kernel),
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interrupt latency for all other peripherals increases and occasional
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lockups occur. That's because both the FIQ and the normal USB interrupt
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fire simultaneously:
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On a multicore Raspberry Pi, if normal interrupts are routed to CPU 0
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and the FIQ to CPU 1 (hardcoded in the Foundation's kernel), then a USB
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interrupt causes CPU 0 to spin in bcm2836_chained_handle_irq() until the
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FIQ on CPU 1 has cleared it. Other peripherals' interrupts are starved
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as long. I've seen CPU 0 blocked for up to 2.9 msec. eMMC throughput
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on a Compute Module 3 irregularly dips to 23.0 MB/s without this commit
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but remains relatively constant at 23.5 MB/s with this commit.
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The lockups occur when CPU 0 receives a USB interrupt while holding a
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lock which CPU 1 is trying to acquire while the FIQ is temporarily
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disabled on CPU 1. At best users get RCU CPU stall warnings, but most
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of the time the system just freezes.
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Fixes: 89214f009c1d ("ARM: bcm2835: add interrupt controller driver")
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Signed-off-by: Lukas Wunner <lukas@wunner.de>
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Signed-off-by: Marc Zyngier <maz@kernel.org>
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Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
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Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
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Link: https://lore.kernel.org/r/f97868ba4e9b86ddad71f44ec9d8b3b7d8daa1ea.1582618537.git.lukas@wunner.de
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---
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drivers/irqchip/irq-bcm2835.c | 21 +++++++++++++++++----
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1 file changed, 17 insertions(+), 4 deletions(-)
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--- a/drivers/irqchip/irq-bcm2835.c
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+++ b/drivers/irqchip/irq-bcm2835.c
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@@ -67,8 +67,7 @@
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#define ARM_LOCAL_GPU_INT_ROUTING 0x0c
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#define REG_FIQ_CONTROL 0x0c
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-#define REG_FIQ_ENABLE 0x80
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-#define REG_FIQ_DISABLE 0
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+#define FIQ_CONTROL_ENABLE BIT(7)
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#define NR_BANKS 3
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#define IRQS_PER_BANK 32
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@@ -116,7 +115,7 @@ static inline unsigned int hwirq_to_fiq(
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static void armctrl_mask_irq(struct irq_data *d)
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{
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if (d->hwirq >= NUMBER_IRQS)
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- writel_relaxed(REG_FIQ_DISABLE, intc.base + REG_FIQ_CONTROL);
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+ writel_relaxed(0, intc.base + REG_FIQ_CONTROL);
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else
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writel_relaxed(HWIRQ_BIT(d->hwirq),
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intc.disable[HWIRQ_BANK(d->hwirq)]);
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@@ -143,7 +142,7 @@ static void armctrl_unmask_irq(struct ir
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ARM_LOCAL_GPU_INT_ROUTING);
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}
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- writel_relaxed(REG_FIQ_ENABLE | hwirq_to_fiq(d->hwirq),
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+ writel_relaxed(FIQ_CONTROL_ENABLE | hwirq_to_fiq(d->hwirq),
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intc.base + REG_FIQ_CONTROL);
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} else {
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writel_relaxed(HWIRQ_BIT(d->hwirq),
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@@ -201,6 +200,7 @@ static int __init armctrl_of_init(struct
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{
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void __iomem *base;
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int irq = 0, last_irq, b, i;
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+ u32 reg;
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base = of_iomap(node, 0);
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if (!base)
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@@ -224,6 +224,19 @@ static int __init armctrl_of_init(struct
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handle_level_irq);
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irq_set_probe(irq);
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}
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+
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+ reg = readl_relaxed(intc.enable[b]);
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+ if (reg) {
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+ writel_relaxed(reg, intc.disable[b]);
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+ pr_err(FW_BUG "Bootloader left irq enabled: "
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+ "bank %d irq %*pbl\n", b, IRQS_PER_BANK, ®);
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+ }
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+ }
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+
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+ reg = readl_relaxed(base + REG_FIQ_CONTROL);
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+ if (reg & FIQ_CONTROL_ENABLE) {
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+ writel_relaxed(0, base + REG_FIQ_CONTROL);
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+ pr_err(FW_BUG "Bootloader left fiq enabled\n");
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}
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last_irq = irq;
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