Hi,
On Mon, Jun 22, 2020 at 2:33 AM Maulik Shah <mkshah@xxxxxxxxxxxxxx> wrote:
>
> Clear previous kernel's configuration during init by resetting
> all interrupts in enable bank to zero.
>
> Signed-off-by: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
> ---
> drivers/irqchip/qcom-pdc.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
> index 8beb6f7..11a9d3a 100644
> --- a/drivers/irqchip/qcom-pdc.c
> +++ b/drivers/irqchip/qcom-pdc.c
> @@ -19,6 +19,7 @@
> #include <linux/slab.h>
> #include <linux/types.h>
>
> +#define PDC_MAX_IRQS_PER_REG 32
> #define PDC_MAX_IRQS 168
> #define PDC_MAX_GPIO_IRQS 256
>
> @@ -339,6 +340,7 @@ static const struct irq_domain_ops qcom_pdc_gpio_ops = {
> static int pdc_setup_pin_mapping(struct device_node *np)
> {
> int ret, n;
> + u32 reg, max_regs, max_pins = 0;
>
> n = of_property_count_elems_of_size(np, "qcom,pdc-ranges", sizeof(u32));
> if (n <= 0 || n % 3)
> @@ -367,8 +369,19 @@ static int pdc_setup_pin_mapping(struct device_node *np)
> &pdc_region[n].cnt);
> if (ret)
> return ret;
> + max_pins += pdc_region[n].cnt;
> }
>
> + if (max_pins > PDC_MAX_IRQS)
> + return -EINVAL;
> +
> + max_regs = max_pins / PDC_MAX_IRQS_PER_REG;
> + if (max_pins % PDC_MAX_IRQS_PER_REG)
> + max_regs++;
nit: max_regs = DIV_ROUND_UP(max_pins, PDC_MAX_IRQS_PER_REG)
> + for (reg = 0; reg < max_regs; reg++)
> + pdc_reg_write(IRQ_ENABLE_BANK, reg, 0);
This doesn't feel correct to me, but maybe I'm misunderstanding the
hardware (I don't think I have access to a reference manual). Looking
at the example in the bindings, I see:
qcom,pdc-ranges = <0 512 94>, <94 641 15>, <115 662 7>;
In that example we have mappings for PDC ports:
0 - 93 (count = 94)
94 - 108 (count = 15)
115 - 121 (count = 7)
Notice the slight discontinuity there. I presume that discontinuity
is normal / allowed? If so, if there is enough of it then I think
your math could be wrong, though with the example you get lucky and it
works out OK. It's easy to see the problem with a slightly different
example: Imagine that you had this:
0 - 33 (count = 34)
94 - 108 (count = 15)
115 - 121 (count = 7)
...now max_pins = 56 and max_regs = 2. So you'll init reg 0 and 1.
...but (IIUC) you actually should be initting 0, 1, 2, and 3.
I have no idea what might be in those discontinuous ranges and if it's
always OK to clear, but (assuming it is) one fix is to put your
clearing loop _inside_ the other "for" loop in this function, AKA:
for (reg = pdc_region[n].pin_base / PDC_MAX_IRQS_PER_REG;
reg < DIV_ROUND_UP(pdc_region[n].pin_base + pdc_region[n].cnt),
PDC_MAX_IRQS_PER_REG)
reg++)
...or another option is to keep track of the max "pin_base + cnt" and
loop from 0 to there? I just don't know your hardware well enough to
tell which would be right.
