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Message-ID: <CAHp75Vc9XSZZ2eyu=2reqNS22Op6a9g6W--1Zf3z_LZmXDeRtQ@mail.gmail.com>
Date: Thu, 26 Jan 2017 02:44:11 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Agustin Vega-Frias <agustinv@...eaurora.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Marc Zyngier <marc.zyngier@....com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Timur Tabi <timur@...eaurora.org>,
Christopher Covington <cov@...eaurora.org>,
Andy Gross <agross@...eaurora.org>, harba@...eaurora.org,
Jon Masters <jcm@...hat.com>, msalter@...hat.com,
mlangsdo@...hat.com, Al Stone <ahs3@...hat.com>, astone@...hat.com,
Graeme Gregory <graeme.gregory@...aro.org>,
guohanjun@...wei.com,
Charles Garcia-Tobin <charles.garcia-tobin@....com>
Subject: Re: [PATCH V11 3/3] irqchip: qcom: Add IRQ combiner driver
On Fri, Jan 20, 2017 at 4:34 AM, Agustin Vega-Frias
<agustinv@...eaurora.org> wrote:
> Driver for interrupt combiners in the Top-level Control and Status
> Registers (TCSR) hardware block in Qualcomm Technologies chips.
>
> An interrupt combiner in this block combines a set of interrupts by
> OR'ing the individual interrupt signals into a summary interrupt
> signal routed to a parent interrupt controller, and provides read-
> only, 32-bit registers to query the status of individual interrupts.
> The status bit for IRQ n is bit (n % 32) within register (n / 32)
> of the given combiner. Thus, each combiner can be described as a set
> of register offsets and the number of IRQs managed.
> +static inline u32 irq_register(int irq)
> +{
> + return irq / REG_SIZE;
> +}
> +
> +static inline u32 irq_bit(int irq)
> +{
> + return irq % REG_SIZE;
> +
> +}
Besides extra line I do not see a benefit of those helpers. On first
glance they even increase characters to type.
> +static inline int irq_nr(u32 reg, u32 bit)
> +{
> + return reg * REG_SIZE + bit;
> +}
This one might make sense.
> +static void combiner_handle_irq(struct irq_desc *desc)
> +{
> + struct combiner *combiner = irq_desc_get_handler_data(desc);
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + u32 reg;
> +
> + chained_irq_enter(chip, desc);
> +
> + for (reg = 0; reg < combiner->nregs; reg++) {
> + int virq;
> + int hwirq;
> + u32 bit;
> + u32 status;
> +
> + bit = readl_relaxed(combiner->regs[reg].addr);
> + status = bit & combiner->regs[reg].enabled;
> + if (!status)
> + pr_warn_ratelimited("Unexpected IRQ on CPU%d: (%08x %08lx %p)\n",
> + smp_processor_id(), bit,
> + combiner->regs[reg].enabled,
> + combiner->regs[reg].addr);
> +
> + while (status) {
> + bit = __ffs(status);
> + status &= ~(1 << bit);
Interesting way of for_each_set_bit() ?
> + hwirq = irq_nr(reg, bit);
> + virq = irq_find_mapping(combiner->domain, hwirq);
> + if (virq > 0)
> + generic_handle_irq(virq);
> +
> + }
> + }
> +
> + chained_irq_exit(chip, desc);
> +}
> +
> +/*
> + * irqchip callbacks
> + */
Useless.
> +/*
> + * irq_domain_ops callbacks
> + */
Ditto.
> +/*
> + * Device probing
> + */
Ditto.
> +static acpi_status count_registers_cb(struct acpi_resource *ares, void *context)
> +{
> + int *count = context;
I would consider to define a struct. It would be easy to extend if needed and...
> +
> + if (ares->type == ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
> + ++(*count);
...allows not to use such of constructions. (I think above is
equivalent to ++*count).
> + return AE_OK;
> +}
> +
> +static int count_registers(struct platform_device *pdev)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
You don't use adev, so, ACPI_HANDLE() ?
> + acpi_status status;
> + int count = 0;
> +
> + if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
> + return -EINVAL;
> +
> + status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> + count_registers_cb, &count);
> + if (ACPI_FAILURE(status))
> + return -EINVAL;
> + return count;
> +}
Oh, since you are using this just as a helper to get count first, why
not to combine this in one callback?
What's the benefit of separation?
> +
> +struct get_registers_context {
> + struct device *dev;
> + struct combiner *combiner;
> + int err;
> +};
> +
> +static acpi_status get_registers_cb(struct acpi_resource *ares, void *context)
> +{
> + struct get_registers_context *ctx = context;
> + struct acpi_resource_generic_register *reg;
> + phys_addr_t paddr;
> + void __iomem *vaddr;
> +
> + if (ares->type != ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
> + return AE_OK;
> +
> + reg = &ares->data.generic_reg;
> + paddr = reg->address;
> + if ((reg->space_id != ACPI_SPACE_MEM) ||
> + (reg->bit_offset != 0) ||
> + (reg->bit_width > REG_SIZE)) {
> + dev_err(ctx->dev, "Bad register resource @%pa\n", &paddr);
> + ctx->err = -EINVAL;
> + return AE_ERROR;
> + }
> +
> + vaddr = devm_ioremap(ctx->dev, reg->address, REG_SIZE);
> + if (IS_ERR(vaddr)) {
> + dev_err(ctx->dev, "Can't map register @%pa\n", &paddr);
> + ctx->err = PTR_ERR(vaddr);
> + return AE_ERROR;
> + }
This all sounds to me like an OperationalRegion. But I'm not sure it's
suitable here.
Do you have ACPI table carved in stone?
> +
> + ctx->combiner->regs[ctx->combiner->nregs].addr = vaddr;
> + ctx->combiner->nirqs += reg->bit_width;
> + ctx->combiner->nregs++;
> + return AE_OK;
> +}
> +
> +static int get_registers(struct platform_device *pdev, struct combiner *comb)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
> + acpi_status status;
> + struct get_registers_context ctx;
> +
> + if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
> + return -EINVAL;
> +
> + ctx.dev = &pdev->dev;
> + ctx.combiner = comb;
> + ctx.err = 0;
> +
> + status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> + get_registers_cb, &ctx);
> + if (ACPI_FAILURE(status))
> + return ctx.err;
> + return 0;
> +}
> +
> +static int __init combiner_probe(struct platform_device *pdev)
> +{
> + struct combiner *combiner;
> + size_t alloc_sz;
> + u32 nregs;
> + int err;
> +
> + nregs = count_registers(pdev);
> + if (nregs <= 0) {
> + dev_err(&pdev->dev, "Error reading register resources\n");
> + return -EINVAL;
> + }
> +
> + alloc_sz = sizeof(*combiner) + sizeof(struct combiner_reg) * nregs;
> + combiner = devm_kzalloc(&pdev->dev, alloc_sz, GFP_KERNEL);
> + if (!combiner)
> + return -ENOMEM;
> +
> + err = get_registers(pdev, combiner);
> + if (err < 0)
> + return err;
> +
> + combiner->parent_irq = platform_get_irq(pdev, 0);
> + if (combiner->parent_irq <= 0) {
> + dev_err(&pdev->dev, "Error getting IRQ resource\n");
> + return -EPROBE_DEFER;
> + }
> +
> + combiner->domain = irq_domain_create_linear(pdev->dev.fwnode, combiner->nirqs,
> + &domain_ops, combiner);
> + if (!combiner->domain)
> + /* Errors printed by irq_domain_create_linear */
> + return -ENODEV;
> +
> + irq_set_chained_handler_and_data(combiner->parent_irq,
> + combiner_handle_irq, combiner);
> +
> + dev_info(&pdev->dev, "Initialized with [p=%d,n=%d,r=%p]\n",
> + combiner->parent_irq, combiner->nirqs, combiner->regs[0].addr);
> + return 0;
> +}
> +
> +static const struct acpi_device_id qcom_irq_combiner_ids[] __dsdt_irqchip = {
> + { "QCOM80B1", },
> + { }
> +};
> +
> +static struct platform_driver qcom_irq_combiner_probe = {
> + .driver = {
> + .name = "qcom-irq-combiner",
> + .owner = THIS_MODULE,
Do you still need this?
> + .acpi_match_table = ACPI_PTR(qcom_irq_combiner_ids),
> + },
--
With Best Regards,
Andy Shevchenko
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