forked from Minki/linux
fce8dc5e50
Simon Horman reported that Koelsch and Lager hang during boot, and bisected this to commit1c3c5eab17("sched/core: Enable might_sleep() and smp_processor_id() checks early"). The da9063/da9210 regulator quirk for R-Car Gen2 boards uses a bus notifier, and unregisters the notifier when it is no longer needed. However, a notifier must not be unregistered from within the call chain. This bug went unnoticed, as blocking_notifier_chain_unregister() didn't take the semaphore during early boot. The aforementioned commit changed that behavior, leading to a deadlock. Fix this by removing the call to bus_unregister_notifier(), and keeping local completion state instead. Reported-by: Simon Horman <horms+renesas@verge.net.au> Fixes:663fbb5215("ARM: shmobile: R-Car Gen2: Add da9063/da9210 regulator quirk") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
143 lines
4.0 KiB
C
143 lines
4.0 KiB
C
/*
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* R-Car Generation 2 da9063/da9210 regulator quirk
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*
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* The r8a7790/lager and r8a7791/koelsch development boards have da9063 and
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* da9210 regulators. Both regulators have their interrupt request lines tied
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* to the same interrupt pin (IRQ2) on the SoC.
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*
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* After cold boot or da9063-induced restart, both the da9063 and da9210 seem
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* to assert their interrupt request lines. Hence as soon as one driver
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* requests this irq, it gets stuck in an interrupt storm, as it only manages
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* to deassert its own interrupt request line, and the other driver hasn't
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* installed an interrupt handler yet.
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*
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* To handle this, install a quirk that masks the interrupts in both the
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* da9063 and da9210. This quirk has to run after the i2c master driver has
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* been initialized, but before the i2c slave drivers are initialized.
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*
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* Copyright (C) 2015 Glider bvba
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/device.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/notifier.h>
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#include <linux/of.h>
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#include <linux/mfd/da9063/registers.h>
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#define IRQC_BASE 0xe61c0000
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#define IRQC_MONITOR 0x104 /* IRQn Signal Level Monitor Register */
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#define REGULATOR_IRQ_MASK BIT(2) /* IRQ2, active low */
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/* start of DA9210 System Control and Event Registers */
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#define DA9210_REG_MASK_A 0x54
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static void __iomem *irqc;
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/* first byte sets the memory pointer, following are consecutive reg values */
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static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
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static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
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static struct i2c_msg da9xxx_msgs[2] = {
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{
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.addr = 0x58,
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.len = ARRAY_SIZE(da9063_irq_clr),
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.buf = da9063_irq_clr,
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}, {
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.addr = 0x68,
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.len = ARRAY_SIZE(da9210_irq_clr),
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.buf = da9210_irq_clr,
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},
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};
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static int regulator_quirk_notify(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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struct device *dev = data;
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struct i2c_client *client;
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static bool done;
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u32 mon;
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if (done)
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return 0;
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mon = ioread32(irqc + IRQC_MONITOR);
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dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
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if (mon & REGULATOR_IRQ_MASK)
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goto remove;
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if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
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return 0;
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client = to_i2c_client(dev);
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dev_dbg(dev, "Detected %s\n", client->name);
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if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
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(client->addr == 0x68 && !strcmp(client->name, "da9210"))) {
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int ret;
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dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
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ret = i2c_transfer(client->adapter, da9xxx_msgs, ARRAY_SIZE(da9xxx_msgs));
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if (ret != ARRAY_SIZE(da9xxx_msgs))
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dev_err(&client->dev, "i2c error %d\n", ret);
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}
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mon = ioread32(irqc + IRQC_MONITOR);
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if (mon & REGULATOR_IRQ_MASK)
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goto remove;
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return 0;
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remove:
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dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
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done = true;
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iounmap(irqc);
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return 0;
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}
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static struct notifier_block regulator_quirk_nb = {
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.notifier_call = regulator_quirk_notify
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};
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static int __init rcar_gen2_regulator_quirk(void)
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{
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u32 mon;
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if (!of_machine_is_compatible("renesas,koelsch") &&
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!of_machine_is_compatible("renesas,lager") &&
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!of_machine_is_compatible("renesas,gose"))
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return -ENODEV;
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irqc = ioremap(IRQC_BASE, PAGE_SIZE);
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if (!irqc)
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return -ENOMEM;
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mon = ioread32(irqc + IRQC_MONITOR);
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if (mon & REGULATOR_IRQ_MASK) {
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pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
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__func__);
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iounmap(irqc);
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return 0;
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}
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pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
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bus_register_notifier(&i2c_bus_type, ®ulator_quirk_nb);
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return 0;
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}
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arch_initcall(rcar_gen2_regulator_quirk);
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