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SubjectRe: [PATCH 2/3] irqchip: stm32: protect configuration registers with hwspinlock
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On 13/11/2018 14:48, Benjamin Gaignard wrote:
> If a hwspinlock is defined in device tree use it to protect
> configuration registers.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
> drivers/irqchip/irq-stm32-exti.c | 36 ++++++++++++++++++++++++++++++------
> 1 file changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/irqchip/irq-stm32-exti.c b/drivers/irqchip/irq-stm32-exti.c
> index 0a2088e12d96..a010a2eed078 100644
> --- a/drivers/irqchip/irq-stm32-exti.c
> +++ b/drivers/irqchip/irq-stm32-exti.c
> @@ -6,6 +6,7 @@
> */
>
> #include <linux/bitops.h>
> +#include <linux/hwspinlock.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/irq.h>
> @@ -20,6 +21,8 @@
>
> #define IRQS_PER_BANK 32
>
> +#define HWSPINLOCK_TIMEOUT 5 /* msec */
> +
> struct stm32_exti_bank {
> u32 imr_ofst;
> u32 emr_ofst;
> @@ -47,6 +50,7 @@ struct stm32_exti_drv_data {
> struct stm32_exti_chip_data {
> struct stm32_exti_host_data *host_data;
> const struct stm32_exti_bank *reg_bank;
> + struct hwspinlock *hwlock;
> struct raw_spinlock rlock;
> u32 wake_active;
> u32 mask_cache;
> @@ -275,25 +279,34 @@ static int stm32_irq_set_type(struct irq_data *d, unsigned int type)
> struct stm32_exti_chip_data *chip_data = gc->private;
> const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;
> u32 rtsr, ftsr;
> - int err;
> + int err = 0;
>
> irq_gc_lock(gc);
>
> + if (chip_data->hwlock)
> + err = hwspin_lock_timeout(chip_data->hwlock,
> + HWSPINLOCK_TIMEOUT);
> +
> + if (err)
> + goto unlock;
> +
> rtsr = irq_reg_readl(gc, stm32_bank->rtsr_ofst);
> ftsr = irq_reg_readl(gc, stm32_bank->ftsr_ofst);
>
> err = stm32_exti_set_type(d, type, &rtsr, &ftsr);
> - if (err) {
> - irq_gc_unlock(gc);
> - return err;
> - }
> + if (err)
> + goto unspinlock;
>
> irq_reg_writel(gc, rtsr, stm32_bank->rtsr_ofst);
> irq_reg_writel(gc, ftsr, stm32_bank->ftsr_ofst);
>
> +unspinlock:
> + if (chip_data->hwlock)
> + hwspin_unlock(chip_data->hwlock);
> +unlock:
> irq_gc_unlock(gc);
>
> - return 0;
> + return err;
> }
>
> static void stm32_chip_suspend(struct stm32_exti_chip_data *chip_data,
> @@ -670,6 +683,7 @@ static int __init stm32_exti_init(const struct stm32_exti_drv_data *drv_data,
> int nr_irqs, ret, i;
> struct irq_chip_generic *gc;
> struct irq_domain *domain;
> + struct hwspinlock *hwlock = NULL;
>
> host_data = stm32_exti_host_init(drv_data, node);
> if (!host_data)
> @@ -692,12 +706,22 @@ static int __init stm32_exti_init(const struct stm32_exti_drv_data *drv_data,
> goto out_free_domain;
> }
>
> + /* hwspinlock is optional */
> + ret = of_hwspin_lock_get_id(node, 0);
> + if (ret < 0) {
> + if (ret == -EPROBE_DEFER)
> + goto out_free_domain;

Wouldn't it make sense to probe for this before allocating the domain?

> + } else {
> + hwlock = hwspin_lock_request_specific(ret);
> + }
> +
> for (i = 0; i < drv_data->bank_nr; i++) {
> const struct stm32_exti_bank *stm32_bank;
> struct stm32_exti_chip_data *chip_data;
>
> stm32_bank = drv_data->exti_banks[i];
> chip_data = stm32_exti_chip_init(host_data, i, node);
> + chip_data->hwlock = hwlock;
>
> gc = irq_get_domain_generic_chip(domain, i * IRQS_PER_BANK);
>
>

Thanks,

M.
--
Jazz is not dead. It just smells funny...

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