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Message-ID: <20180206224348.GA16504@codeaurora.org>
Date: Tue, 6 Feb 2018 22:43:48 +0000
From: Lina Iyer <ilina@...eaurora.org>
To: Marc Zyngier <marc.zyngier@....com>
Cc: tglx@...utronix.de, jason@...edaemon.net,
linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
rnayak@...eaurora.org, asathyak@...eaurora.org
Subject: Re: [PATCH v3 1/2] drivers: irqchip: pdc: Add PDC interrupt
controller for QCOM SoCs
On Tue, Feb 06 2018 at 20:34 +0000, Marc Zyngier wrote:
>On Tue, 06 Feb 2018 18:09:04 +0000,
>Lina Iyer wrote:
>> +#define PDC_MAX_IRQS 126
>
>>From v2: "Is that an absolute, architectural maximum? Or should it
>come from the DT (being the sum of all ranges that are provided by
>this PDC)?"
>
Architectural maximum. Sorry I forgot to respond earlier.
>> +static inline void pdc_reg_write(int reg, u32 i, u32 val)
>> +{
>> + writel_relaxed(val, pdc_base + reg + i * sizeof(u32));
>> +}
>> +
>> +static inline u32 pdc_reg_read(int reg, u32 i)
>> +{
>> + return readl_relaxed(pdc_base + reg + i * sizeof(u32));
>> +}
>> +
>> +static inline void pdc_enable_intr(struct irq_data *d, bool on)
>
>You can loose the "inline" on these 3 function, I believe the compiler
>will do a pretty good job specialising them.
>
Ok.
>> + * 3'b0 00 Level sensitive active low LOW
>> + * 3'b0 01 Rising edge sensitive NOT USED
>> + * 3'b0 10 Falling edge sensitive LOW
>> + * 3'b0 11 Dual Edge sensitive NOT USED
>> + * 3'b1 00 Level senstive active High HIGH
>
>sensitive
>
Ok
>> +
>> +static struct irq_chip qcom_pdc_gic_chip = {
>
>const?
>
>> + .name = "pdc-gic",
>
>Just call it "PDC".
>
OK to both.
>> + .irq_eoi = irq_chip_eoi_parent,
>> + .irq_mask = qcom_pdc_gic_mask,
>> + .irq_unmask = qcom_pdc_gic_unmask,
>> + .irq_retrigger = irq_chip_retrigger_hierarchy,
>> + .irq_set_type = qcom_pdc_gic_set_type,
>> + .flags = IRQCHIP_MASK_ON_SUSPEND |
>> + IRQCHIP_SET_TYPE_MASKED |
>> + IRQCHIP_SKIP_SET_WAKE,
>> + .irq_set_vcpu_affinity = irq_chip_set_vcpu_affinity_parent,
>> +#ifdef CONFIG_SMP
>> + .irq_set_affinity = irq_chip_set_affinity_parent,
>> +#endif
>
>Is this supposed to work on any architecture other than arm64? If not,
>then you can loose the CONFIG_SMP, as there is no !SMP config on arm64.
>
Only ARM64 afaict. But who knows ? :)
>> +};
>> +
>> +static irq_hw_number_t get_parent_hwirq(int pin)
>> +{
>> + int i;
>> + struct pdc_pin_region *region;
>> +
>> + for (i = 0; i < pdc_region_cnt; i++) {
>> + region = &pdc_region[i];
>> + if (pin >= region->pin_base &&
>> + pin < region->pin_base + region->cnt)
>> + return (region->parent_base + pin - region->pin_base);
>> + }
>> +
>> + WARN_ON(1);
>> + return pin;
>
>Do not return a valid value in case of error. Please return an error
>value that you will check in the caller. Otherwise you're feeding the
>GIC with a SPI number that is actually a PDC pin number. That is not
>going to have any positive effect.
>
How about the max of irq_hw_number_t ?
>> +static int qcom_pdc_alloc(struct irq_domain *domain,
>> + unsigned int virq, unsigned int nr_irqs, void *data)
>> +{
>> + struct irq_fwspec *fwspec = data;
>> + struct irq_fwspec parent_fwspec;
>> + irq_hw_number_t hwirq, parent_hwirq;
>> + unsigned int type;
>> + int ret;
>> +
>> + ret = qcom_pdc_translate(domain, fwspec, &hwirq, &type);
>> + if (ret)
>> + return -EINVAL;
>> +
>> + parent_hwirq = get_parent_hwirq(hwirq);
>> + ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
>> + &qcom_pdc_gic_chip,
>> + (void *)parent_hwirq);
>
>Nothing else in this driver should be concerned with the parent hwirq,
>so NULL should be an appropriate value for chip_data.
>
Yes, I forgot to remove it. I don't need this anymore.
>> + region = kcalloc(n, sizeof(*region), GFP_KERNEL);
>> + if (!region)
>> + return -ENOMEM;
>> +
>> + ret = of_property_read_u32_array(np, "qcom,pdc-ranges", region, n);
>> + if (ret) {
>> + kfree(region);
>> + return -EINVAL;
>> + }
>> +
>> + pdc_region = (struct pdc_pin_region *)region;
>
>Oh please... Don't resort to that kind of hack. Next thing you know,
>someone will add a u8 field to that structure and you'll spend the
>following 2 hours trying to understand why it all went so wrong.
>Allocate a bounce buffer if you want, copy fields one by one, I don't
>care. Just don't do that. :-(
>
:) ok.
>> + pdc_region_cnt = n / 3;
>> +
>> + return 0;
>> +}
>> +
>> +int qcom_pdc_init(struct device_node *node, struct device_node *parent)
>
>static.
>
OK.
>> +{
>> + struct irq_domain *parent_domain, *pdc_domain;
>> + int ret;
>> +
>> + pdc_base = of_iomap(node, 0);
>> + if (!pdc_base) {
>> + pr_err("%s: unable to map PDC registers\n", node->full_name);
>> + return -ENXIO;
>> + }
>> +
>> + parent_domain = irq_find_host(parent);
>> + if (!parent_domain) {
>> + pr_err("%s: unable to obtain PDC parent domain\n",
>> + node->full_name);
>
>Use %pOF instead of %s and node->full_name in all occurrences in this
>function (see commit ce4fecf1fe15).
>
Sure.
>
>Thanks,
Once again thanks Marc.
-- Lina
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