--- /dev/null
+From 39ce8150a079e3ae6ed9abf26d7918a558ef7c19 Mon Sep 17 00:00:00 2001
+From: Mika Westerberg <mika.westerberg@linux.intel.com>
+Date: Tue, 4 Aug 2015 15:03:14 +0300
+Subject: pinctrl: baytrail: Serialize all register access
+
+From: Mika Westerberg <mika.westerberg@linux.intel.com>
+
+commit 39ce8150a079e3ae6ed9abf26d7918a558ef7c19 upstream.
+
+There is a hardware issue in Intel Baytrail where concurrent GPIO register
+access might result reads of 0xffffffff and writes might get dropped
+completely.
+
+Prevent this from happening by taking the serializing lock in all places
+where it is possible that more than one thread might be accessing the
+hardware concurrently.
+
+Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
+Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
+Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/pinctrl/intel/pinctrl-baytrail.c | 21 ++++++++++++++++-----
+ 1 file changed, 16 insertions(+), 5 deletions(-)
+
+--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
++++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
+@@ -201,6 +201,9 @@ static int byt_gpio_request(struct gpio_
+ struct byt_gpio *vg = to_byt_gpio(chip);
+ void __iomem *reg = byt_gpio_reg(chip, offset, BYT_CONF0_REG);
+ u32 value, gpio_mux;
++ unsigned long flags;
++
++ spin_lock_irqsave(&vg->lock, flags);
+
+ /*
+ * In most cases, func pin mux 000 means GPIO function.
+@@ -214,18 +217,16 @@ static int byt_gpio_request(struct gpio_
+ value = readl(reg) & BYT_PIN_MUX;
+ gpio_mux = byt_get_gpio_mux(vg, offset);
+ if (WARN_ON(gpio_mux != value)) {
+- unsigned long flags;
+-
+- spin_lock_irqsave(&vg->lock, flags);
+ value = readl(reg) & ~BYT_PIN_MUX;
+ value |= gpio_mux;
+ writel(value, reg);
+- spin_unlock_irqrestore(&vg->lock, flags);
+
+ dev_warn(&vg->pdev->dev,
+ "pin %u forcibly re-configured as GPIO\n", offset);
+ }
+
++ spin_unlock_irqrestore(&vg->lock, flags);
++
+ pm_runtime_get(&vg->pdev->dev);
+
+ return 0;
+@@ -277,7 +278,15 @@ static int byt_irq_type(struct irq_data
+ static int byt_gpio_get(struct gpio_chip *chip, unsigned offset)
+ {
+ void __iomem *reg = byt_gpio_reg(chip, offset, BYT_VAL_REG);
+- return readl(reg) & BYT_LEVEL;
++ struct byt_gpio *vg = to_byt_gpio(chip);
++ unsigned long flags;
++ u32 val;
++
++ spin_lock_irqsave(&vg->lock, flags);
++ val = readl(reg);
++ spin_unlock_irqrestore(&vg->lock, flags);
++
++ return val & BYT_LEVEL;
+ }
+
+ static void byt_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+@@ -450,8 +459,10 @@ static void byt_irq_ack(struct irq_data
+ unsigned offset = irqd_to_hwirq(d);
+ void __iomem *reg;
+
++ spin_lock(&vg->lock);
+ reg = byt_gpio_reg(&vg->chip, offset, BYT_INT_STAT_REG);
+ writel(BIT(offset % 32), reg);
++ spin_unlock(&vg->lock);
+ }
+
+ static void byt_irq_unmask(struct irq_data *d)
--- /dev/null
+From 78e1c896932df5b8bcdff7bf5417d8e72a4d0d6b Mon Sep 17 00:00:00 2001
+From: Mika Westerberg <mika.westerberg@linux.intel.com>
+Date: Mon, 17 Aug 2015 16:03:17 +0300
+Subject: pinctrl: baytrail: Use raw_spinlock for locking
+
+From: Mika Westerberg <mika.westerberg@linux.intel.com>
+
+commit 78e1c896932df5b8bcdff7bf5417d8e72a4d0d6b upstream.
+
+The Intel Baytrail pinctrl driver implements irqchip callbacks which are
+called with desc->lock raw_spinlock held. In mainline this is fine because
+spinlock resolves to raw_spinlock. However, running the same code in -rt we
+get:
+
+ BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
+ in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/0
+ Preemption disabled at:[<ffffffff81092e9f>] cpu_startup_entry+0x17f/0x480
+
+ CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.5-rt5 #13
+ ...
+ Call Trace:
+ <IRQ> [<ffffffff816283c6>] dump_stack+0x4a/0x61
+ [<ffffffff81077e17>] ___might_sleep+0xe7/0x170
+ [<ffffffff8162d6cf>] rt_spin_lock+0x1f/0x50
+ [<ffffffff812e3b88>] byt_gpio_clear_triggering+0x38/0x60
+ [<ffffffff812e3bc1>] byt_irq_mask+0x11/0x20
+ [<ffffffff810a7013>] handle_level_irq+0x83/0x150
+ [<ffffffff810a3457>] generic_handle_irq+0x27/0x40
+ [<ffffffff812e3a5f>] byt_gpio_irq_handler+0x7f/0xc0
+ [<ffffffff810050aa>] handle_irq+0xaa/0x190
+ ...
+
+This is because in -rt spinlocks are preemptible so taking the driver
+private spinlock in irqchip callbacks causes might_sleep() to trigger.
+
+In order to keep -rt happy but at the same time make sure that register
+accesses get serialized, convert the driver to use raw_spinlock instead.
+
+Also shorten the critical section a bit in few places.
+
+Suggested-by: Linus Walleij <linus.walleij@linaro.org>
+Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
+Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
+Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/pinctrl/intel/pinctrl-baytrail.c | 50 +++++++++++++++----------------
+ 1 file changed, 25 insertions(+), 25 deletions(-)
+
+--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
++++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
+@@ -146,7 +146,7 @@ struct byt_gpio_pin_context {
+ struct byt_gpio {
+ struct gpio_chip chip;
+ struct platform_device *pdev;
+- spinlock_t lock;
++ raw_spinlock_t lock;
+ void __iomem *reg_base;
+ struct pinctrl_gpio_range *range;
+ struct byt_gpio_pin_context *saved_context;
+@@ -174,11 +174,11 @@ static void byt_gpio_clear_triggering(st
+ unsigned long flags;
+ u32 value;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+ value = readl(reg);
+ value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL);
+ writel(value, reg);
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+ }
+
+ static u32 byt_get_gpio_mux(struct byt_gpio *vg, unsigned offset)
+@@ -203,7 +203,7 @@ static int byt_gpio_request(struct gpio_
+ u32 value, gpio_mux;
+ unsigned long flags;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+
+ /*
+ * In most cases, func pin mux 000 means GPIO function.
+@@ -225,7 +225,7 @@ static int byt_gpio_request(struct gpio_
+ "pin %u forcibly re-configured as GPIO\n", offset);
+ }
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ pm_runtime_get(&vg->pdev->dev);
+
+@@ -251,7 +251,7 @@ static int byt_irq_type(struct irq_data
+ if (offset >= vg->chip.ngpio)
+ return -EINVAL;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+ value = readl(reg);
+
+ WARN(value & BYT_DIRECT_IRQ_EN,
+@@ -270,7 +270,7 @@ static int byt_irq_type(struct irq_data
+ else if (type & IRQ_TYPE_LEVEL_MASK)
+ __irq_set_handler_locked(d->irq, handle_level_irq);
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ return 0;
+ }
+@@ -282,9 +282,9 @@ static int byt_gpio_get(struct gpio_chip
+ unsigned long flags;
+ u32 val;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+ val = readl(reg);
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ return val & BYT_LEVEL;
+ }
+@@ -296,7 +296,7 @@ static void byt_gpio_set(struct gpio_chi
+ unsigned long flags;
+ u32 old_val;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+
+ old_val = readl(reg);
+
+@@ -305,7 +305,7 @@ static void byt_gpio_set(struct gpio_chi
+ else
+ writel(old_val & ~BYT_LEVEL, reg);
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+ }
+
+ static int byt_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+@@ -315,13 +315,13 @@ static int byt_gpio_direction_input(stru
+ unsigned long flags;
+ u32 value;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+
+ value = readl(reg) | BYT_DIR_MASK;
+ value &= ~BYT_INPUT_EN; /* active low */
+ writel(value, reg);
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ return 0;
+ }
+@@ -335,7 +335,7 @@ static int byt_gpio_direction_output(str
+ unsigned long flags;
+ u32 reg_val;
+
+- spin_lock_irqsave(&vg->lock, flags);
++ raw_spin_lock_irqsave(&vg->lock, flags);
+
+ /*
+ * Before making any direction modifications, do a check if gpio
+@@ -354,7 +354,7 @@ static int byt_gpio_direction_output(str
+ else
+ writel(reg_val & ~BYT_LEVEL, reg);
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ return 0;
+ }
+@@ -363,18 +363,19 @@ static void byt_gpio_dbg_show(struct seq
+ {
+ struct byt_gpio *vg = to_byt_gpio(chip);
+ int i;
+- unsigned long flags;
+ u32 conf0, val, offs;
+
+- spin_lock_irqsave(&vg->lock, flags);
+-
+ for (i = 0; i < vg->chip.ngpio; i++) {
+ const char *pull_str = NULL;
+ const char *pull = NULL;
++ unsigned long flags;
+ const char *label;
+ offs = vg->range->pins[i] * 16;
++
++ raw_spin_lock_irqsave(&vg->lock, flags);
+ conf0 = readl(vg->reg_base + offs + BYT_CONF0_REG);
+ val = readl(vg->reg_base + offs + BYT_VAL_REG);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+
+ label = gpiochip_is_requested(chip, i);
+ if (!label)
+@@ -427,7 +428,6 @@ static void byt_gpio_dbg_show(struct seq
+
+ seq_puts(s, "\n");
+ }
+- spin_unlock_irqrestore(&vg->lock, flags);
+ }
+
+ static void byt_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+@@ -459,10 +459,10 @@ static void byt_irq_ack(struct irq_data
+ unsigned offset = irqd_to_hwirq(d);
+ void __iomem *reg;
+
+- spin_lock(&vg->lock);
++ raw_spin_lock(&vg->lock);
+ reg = byt_gpio_reg(&vg->chip, offset, BYT_INT_STAT_REG);
+ writel(BIT(offset % 32), reg);
+- spin_unlock(&vg->lock);
++ raw_spin_unlock(&vg->lock);
+ }
+
+ static void byt_irq_unmask(struct irq_data *d)
+@@ -474,9 +474,9 @@ static void byt_irq_unmask(struct irq_da
+ void __iomem *reg;
+ u32 value;
+
+- spin_lock_irqsave(&vg->lock, flags);
+-
+ reg = byt_gpio_reg(&vg->chip, offset, BYT_CONF0_REG);
++
++ raw_spin_lock_irqsave(&vg->lock, flags);
+ value = readl(reg);
+
+ switch (irqd_get_trigger_type(d)) {
+@@ -497,7 +497,7 @@ static void byt_irq_unmask(struct irq_da
+
+ writel(value, reg);
+
+- spin_unlock_irqrestore(&vg->lock, flags);
++ raw_spin_unlock_irqrestore(&vg->lock, flags);
+ }
+
+ static void byt_irq_mask(struct irq_data *d)
+@@ -589,7 +589,7 @@ static int byt_gpio_probe(struct platfor
+ if (IS_ERR(vg->reg_base))
+ return PTR_ERR(vg->reg_base);
+
+- spin_lock_init(&vg->lock);
++ raw_spin_lock_init(&vg->lock);
+
+ gc = &vg->chip;
+ gc->label = dev_name(&pdev->dev);
projects / thirdparty / kernel / stable-queue.git / commitdiff
