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>

1 files changed, 12 insertions, 19 deletions

diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
index 8fb474f03940..cf3228b0ab90 100644
--- 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);