Input: tegra-kbc - tighten locking

Take spinlock when entering ISR and timer routine to ensure that we do not
race while enabling/disabling FIFO interrupts.

Also we do not need to take teh spinlock in tegra_kbc_startremove() since
interrupt is completely disabled.

Tested-by: Rakesh Iyer <riyer@nvidia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
index 8fb474f..cf3228b 100644 (file)
--- a/drivers/input/keyboard/tegra-kbc.c
+++ b/drivers/input/keyboard/tegra-kbc.c
@@ -260,12 +260,10 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc)
        u32 val = 0;
        unsigned int i;
        unsigned int num_down = 0;
-       unsigned long flags;
        bool fn_keypress = false;
        bool key_in_same_row = false;
        bool key_in_same_col = false;
 
-       spin_lock_irqsave(&kbc->lock, flags);
        for (i = 0; i < KBC_MAX_KPENT; i++) {
                if ((i % 4) == 0)
                        val = readl(kbc->mmio + KBC_KP_ENT0_0 + i);
@@ -294,7 +292,7 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc)
         * any 2 of the 3 keys share a row, and any 2 of them share a column.
         * If so ignore the key presses for this iteration.
         */
-       if ((kbc->use_ghost_filter) && (num_down >= 3)) {
+       if (kbc->use_ghost_filter && num_down >= 3) {
                for (i = 0; i < num_down; i++) {
                        unsigned int j;
                        u8 curr_col = scancodes[i] & 0x07;
@@ -327,8 +325,6 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc)
                }
        }
 
-       spin_unlock_irqrestore(&kbc->lock, flags);
-
        /* Ignore the key presses for this iteration? */
        if (key_in_same_col && key_in_same_row)
                return;
@@ -362,6 +358,8 @@ static void tegra_kbc_keypress_timer(unsigned long data)
        u32 val;
        unsigned int i;
 
+       spin_lock_irqsave(&kbc->lock, flags);
+
        val = (readl(kbc->mmio + KBC_INT_0) >> 4) & 0xf;
        if (val) {
                unsigned long dly;
@@ -383,22 +381,19 @@ static void tegra_kbc_keypress_timer(unsigned long data)
                kbc->num_pressed_keys = 0;
 
                /* All keys are released so enable the keypress interrupt */
-               spin_lock_irqsave(&kbc->lock, flags);
                tegra_kbc_set_fifo_interrupt(kbc, true);
-               spin_unlock_irqrestore(&kbc->lock, flags);
        }
+
+       spin_unlock_irqrestore(&kbc->lock, flags);
 }
 
 static irqreturn_t tegra_kbc_isr(int irq, void *args)
 {
        struct tegra_kbc *kbc = args;
+       unsigned long flags;
        u32 val;
 
-       /*
-        * Until all keys are released, defer further processing to
-        * the polling loop in tegra_kbc_keypress_timer
-        */
-       tegra_kbc_set_fifo_interrupt(kbc, false);
+       spin_lock_irqsave(&kbc->lock, flags);
 
        /*
         * Quickly bail out & reenable interrupts if the fifo threshold
@@ -409,14 +404,15 @@ static irqreturn_t tegra_kbc_isr(int irq, void *args)
 
        if (val & KBC_INT_FIFO_CNT_INT_STATUS) {
                /*
-                * Schedule timer to run when hardware is in continuous
-                * polling mode.
+                * Until all keys are released, defer further processing to
+                * the polling loop in tegra_kbc_keypress_timer.
                 */
+               tegra_kbc_set_fifo_interrupt(kbc, false);
                mod_timer(&kbc->timer, jiffies + kbc->cp_dly_jiffies);
-       } else {
-               tegra_kbc_set_fifo_interrupt(kbc, true);
        }
 
+       spin_unlock_irqrestore(&kbc->lock, flags);
+
        return IRQ_HANDLED;
 }
 
@@ -464,7 +460,6 @@ static void tegra_kbc_config_pins(struct tegra_kbc *kbc)
 static int tegra_kbc_start(struct tegra_kbc *kbc)
 {
        const struct tegra_kbc_platform_data *pdata = kbc->pdata;
-       unsigned long flags;
        unsigned int debounce_cnt;
        u32 val = 0;
 
@@ -502,7 +497,6 @@ static int tegra_kbc_start(struct tegra_kbc *kbc)
         * Atomically clear out any remaining entries in the key FIFO
         * and enable keyboard interrupts.
         */
-       spin_lock_irqsave(&kbc->lock, flags);
        while (1) {
                val = readl(kbc->mmio + KBC_INT_0);
                val >>= 4;
@@ -513,7 +507,6 @@ static int tegra_kbc_start(struct tegra_kbc *kbc)
                val = readl(kbc->mmio + KBC_KP_ENT1_0);
        }
        writel(0x7, kbc->mmio + KBC_INT_0);
-       spin_unlock_irqrestore(&kbc->lock, flags);
 
        enable_irq(kbc->irq);