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Simple PCIe FMC carrier SPEC
Commit cced5f58 authored by Federico Vaga's avatar Federico Vaga
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sw:drv: handle correctly level interrupts 

While drivers are processing a level interrupts, the bit in GPIO_INT_STATUS
get set and it sticks there. Only when drivers processed the level interrupts
we are sure that the bit does not get set again. Therefore, only at this
point we can properly clean the GPIO_INT_STATUS. Then we may have problems,
with the edge interrupts, so we put them (edge interrupts) back in the
GPIO_INT_STATUS. About this last point we are not sure that is going to work,
but in all our installation we are not going to use edge interrupts because
they are risky.
Signed-off-by: Federico Vaga's avatarFederico Vaga <federico.vaga@cern.ch>
parent c0130faf
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Showing with 18 additions and 1 deletion
software/kernel/gn412x-gpio.c
View file @ cced5f58
......@@ -302,7 +302,7 @@ static irqreturn_t gn412x_gpio_irq_handler_t(int irq, void *arg)
struct gn412x_gpio_dev *gn412x = arg;
struct gpio_chip *gc = &gn412x->gpiochip;
unsigned int cascade_irq;
uint32_t gpio_int_status;
uint32_t gpio_int_status, gpio_int_type;
unsigned long loop;
irqreturn_t ret = IRQ_NONE;
int i;
......@@ -322,6 +322,23 @@ static irqreturn_t gn412x_gpio_irq_handler_t(int irq, void *arg)
*/
handle_nested_irq(cascade_irq);
}
/*
* Level interrupts are cleared only when they are processed. This
* means that at this point (interrupts have been processed) the
* GPIO_INT_STATUS is still set because it is a sticky bit that got
* set again after our first read because we did not handle yet
* the IRQ. For this reason we have to clear it (defentivelly) by
* reading again the register ...
*/
gpio_int_status = gn412x_ioread32(gn412x, GNGPIO_INT_STATUS);
/*
* ... but like this edge interrupts are lost. So write back
* in the register the status of all pending edge interrupts.
* (NOTE: not yet prooven that it works)
*/
gpio_int_type = gn412x_ioread32(gn412x, GNGPIO_INT_TYPE);
gn412x_iowrite32(gn412x, (gpio_int_status & (~gpio_int_type)),
GNGPIO_INT_STATUS);
ret = IRQ_HANDLED;
out_enable_irq:
......
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