pinctrl: renesas: rzg2l: Execute atomically the interrupt configuration

Lockdep detects a possible deadlock as listed below. This is because it
detects the IA55 interrupt controller .irq_eoi() API is called from
interrupt context while configuration-specific API (e.g., .irq_enable())
could be called from process context on resume path (by calling
rzg2l_gpio_irq_restore()). To avoid this, protect the call of
rzg2l_gpio_irq_enable() with spin_lock_irqsave()/spin_unlock_irqrestore().
With this the same approach that is available in __setup_irq() is mimicked
to pinctrl IRQ resume function.

Below is the lockdep report:

    WARNING: inconsistent lock state
    6.8.0-rc5-next-20240219-arm64-renesas-00030-gb17a289abf1f torvalds#90 Not tainted
    --------------------------------
    inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
    str_rwdt_t_001./159 [HC0[0]:SC0[0]:HE1:SE1] takes:
    ffff00000b001d70 (&rzg2l_irqc_data->lock){?...}-{2:2}, at: rzg2l_irqc_irq_enable+0x60/0xa4
    {IN-HARDIRQ-W} state was registered at:
    lock_acquire+0x1e0/0x310
    _raw_spin_lock+0x44/0x58
    rzg2l_irqc_eoi+0x2c/0x130
    irq_chip_eoi_parent+0x18/0x20
    rzg2l_gpio_irqc_eoi+0xc/0x14
    handle_fasteoi_irq+0x134/0x230
    generic_handle_domain_irq+0x28/0x3c
    gic_handle_irq+0x4c/0xbc
    call_on_irq_stack+0x24/0x34
    do_interrupt_handler+0x78/0x7c
    el1_interrupt+0x30/0x5c
    el1h_64_irq_handler+0x14/0x1c
    el1h_64_irq+0x64/0x68
    _raw_spin_unlock_irqrestore+0x34/0x70
    __setup_irq+0x4d4/0x6b8
    request_threaded_irq+0xe8/0x1a0
    request_any_context_irq+0x60/0xb8
    devm_request_any_context_irq+0x74/0x104
    gpio_keys_probe+0x374/0xb08
    platform_probe+0x64/0xcc
    really_probe+0x140/0x2ac
    __driver_probe_device+0x74/0x124
    driver_probe_device+0x3c/0x15c
    __driver_attach+0xec/0x1c4
    bus_for_each_dev+0x70/0xcc
    driver_attach+0x20/0x28
    bus_add_driver+0xdc/0x1d0
    driver_register+0x5c/0x118
    __platform_driver_register+0x24/0x2c
    gpio_keys_init+0x18/0x20
    do_one_initcall+0x70/0x290
    kernel_init_freeable+0x294/0x504
    kernel_init+0x20/0x1cc
    ret_from_fork+0x10/0x20
    irq event stamp: 69071
    hardirqs last enabled at (69071): [<ffff800080e0dafc>] _raw_spin_unlock_irqrestore+0x6c/0x70
    hardirqs last disabled at (69070): [<ffff800080e0cfec>] _raw_spin_lock_irqsave+0x7c/0x80
    softirqs last enabled at (67654): [<ffff800080010614>] __do_softirq+0x494/0x4dc
    softirqs last disabled at (67645): [<ffff800080015238>] ____do_softirq+0xc/0x14

    other info that might help us debug this:
    Possible unsafe locking scenario:

    CPU0
    ----
    lock(&rzg2l_irqc_data->lock);
    <Interrupt>
    lock(&rzg2l_irqc_data->lock);

    *** DEADLOCK ***

    4 locks held by str_rwdt_t_001./159:
    #0: ffff00000b10f3f0 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x1a4/0x35c
    #1: ffff00000e43ba88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe8/0x1a8
    #2: ffff00000aa21dc8 (kn->active#40){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1a8
    #3: ffff80008179d970 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x9c/0x278

    stack backtrace:
    CPU: 0 PID: 159 Comm: str_rwdt_t_001. Not tainted 6.8.0-rc5-next-20240219-arm64-renesas-00030-gb17a289abf1f torvalds#90
    Hardware name: Renesas SMARC EVK version 2 based on r9a08g045s33 (DT)
    Call trace:
    dump_backtrace+0x94/0xe8
    show_stack+0x14/0x1c
    dump_stack_lvl+0x88/0xc4
    dump_stack+0x14/0x1c
    print_usage_bug.part.0+0x294/0x348
    mark_lock+0x6b0/0x948
    __lock_acquire+0x750/0x20b0
    lock_acquire+0x1e0/0x310
    _raw_spin_lock+0x44/0x58
    rzg2l_irqc_irq_enable+0x60/0xa4
    irq_chip_enable_parent+0x1c/0x34
    rzg2l_gpio_irq_enable+0xc4/0xd8
    rzg2l_pinctrl_resume_noirq+0x4cc/0x520
    pm_generic_resume_noirq+0x28/0x3c
    genpd_finish_resume+0xc0/0xdc
    genpd_resume_noirq+0x14/0x1c
    dpm_run_callback+0x34/0x90
    device_resume_noirq+0xa8/0x268
    dpm_noirq_resume_devices+0x13c/0x160
    dpm_resume_noirq+0xc/0x1c
    suspend_devices_and_enter+0x2c8/0x570
    pm_suspend+0x1ac/0x278
    state_store+0x88/0x124
    kobj_attr_store+0x14/0x24
    sysfs_kf_write+0x48/0x6c
    kernfs_fop_write_iter+0x118/0x1a8
    vfs_write+0x270/0x35c
    ksys_write+0x64/0xec
    __arm64_sys_write+0x18/0x20
    invoke_syscall+0x44/0x108
    el0_svc_common.constprop.0+0xb4/0xd4
    do_el0_svc+0x18/0x20
    el0_svc+0x3c/0xb8
    el0t_64_sync_handler+0xb8/0xbc
    el0t_64_sync+0x14c/0x150

Fixes: 254203f ("pinctrl: renesas: rzg2l: Add suspend/resume support")
Signed-off-by: Claudiu Beznea <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>

drivers/pinctrl/renesas/pinctrl-rzg2l.c

@@ -2063,8 +2063,17 @@ static void rzg2l_gpio_irq_restore(struct rzg2l_pinctrl *pctrl)
 			continue;
 		}
 
-		if (!irqd_irq_disabled(data))
+		if (!irqd_irq_disabled(data)) {
+			unsigned long flags;
+
+			/*
+			 * This has to be atomically executed to protect against a concurrent
+			 * interrupt.
+			 */
+			raw_spin_lock_irqsave(&pctrl->lock.rlock, flags);
 			rzg2l_gpio_irq_enable(data);
+			raw_spin_unlock_irqrestore(&pctrl->lock.rlock, flags);
+		}
 	}
 }