Re: [PATCH v2 3/4] irqchip: irq-mtk-cirq: Move register offsets to const array

Marc Zyngier
2022-11-23T13:56:56Z

On Wed, 23 Nov 2022 11:22:48 +0000,
AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> wrote:
>
> In preparation to add support for new SoCs having a different
> register layout, add an enumeration that documents register
> offsets and move the definitions for the same to a u32 array;
>
> Selecting the right register offsets array is done by adding an
> of_device_id array containing all of the currently supported
> compatible strings pointing to the "v1" offsets array (as data):
> since no devicetree declares the `mediatek,mtk-cirq` compatible
> without a SoC-specific one, it wasn't necessary to provide any
> legacy fallback.
>
> Every usage of the aforemementioned definitions was changed to
> get a register address through a newly introduced `mtk_cirq_reg()`
> accessor.
>
> This change brings no functional changes.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> drivers/irqchip/irq-mtk-cirq.c | 78 ++++++++++++++++++++++++++--------
> 1 file changed, 61 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/irqchip/irq-mtk-cirq.c b/drivers/irqchip/irq-mtk-cirq.c
> index 9bca0918078e..4d873d2ba0fd 100644
> --- a/drivers/irqchip/irq-mtk-cirq.c
> +++ b/drivers/irqchip/irq-mtk-cirq.c
> @@ -15,14 +15,29 @@
> #include <linux/slab.h>
> #include <linux/syscore_ops.h>
>
> -#define CIRQ_ACK 0x40
> -#define CIRQ_MASK_SET 0xc0
> -#define CIRQ_MASK_CLR 0x100
> -#define CIRQ_SENS_SET 0x180
> -#define CIRQ_SENS_CLR 0x1c0
> -#define CIRQ_POL_SET 0x240
> -#define CIRQ_POL_CLR 0x280
> -#define CIRQ_CONTROL 0x300
> +enum mtk_cirq_reg_index {
> + CIRQ_STA,
> + CIRQ_ACK,
> + CIRQ_MASK_SET,
> + CIRQ_MASK_CLR,
> + CIRQ_SENS_SET,
> + CIRQ_SENS_CLR,
> + CIRQ_POL_SET,
> + CIRQ_POL_CLR,
> + CIRQ_CONTROL
> +};
> +
> +static const u32 mtk_cirq_regs_v1[] = {

Again: this contains offsets, not registers. Consistency matters.

> + [CIRQ_STA] = 0x0,
> + [CIRQ_ACK] = 0x40,
> + [CIRQ_MASK_SET] = 0xc0,
> + [CIRQ_MASK_CLR] = 0x100,
> + [CIRQ_SENS_SET] = 0x180,
> + [CIRQ_SENS_CLR] = 0x1c0,
> + [CIRQ_POL_SET] = 0x240,
> + [CIRQ_POL_CLR] = 0x280,
> + [CIRQ_CONTROL] = 0x300,
> +};
>
> #define CIRQ_EN 0x1
> #define CIRQ_EDGE 0x2
> @@ -32,18 +47,28 @@ struct mtk_cirq_chip_data {
> void __iomem *base;
> unsigned int ext_irq_start;
> unsigned int ext_irq_end;
> + const u32 *offsets;
> struct irq_domain *domain;
> };
>
> static struct mtk_cirq_chip_data *cirq_data;
>
> -static void mtk_cirq_write_mask(struct irq_data *data, unsigned int offset)
> +static inline void __iomem *mtk_cirq_reg(struct mtk_cirq_chip_data *chip_data,

Drop the inline. That's for the compiler to figure it out.

> + enum mtk_cirq_reg_index idx,
> + unsigned int cirq_num)

What does cirq_num mean for registers that are not relative to an
interrupt? Create a separate helper for those.

> +{
> + void __iomem *reg = chip_data->base + chip_data->offsets[idx];
> +
> + return reg + (cirq_num / 32) * 4;
> +}
> +
> +static void mtk_cirq_write_mask(struct irq_data *data, enum mtk_cirq_reg_index idx)
> {
> struct mtk_cirq_chip_data *chip_data = data->chip_data;
> unsigned int cirq_num = data->hwirq;
> u32 mask = 1 << (cirq_num % 32);
>
> - writel_relaxed(mask, chip_data->base + offset + (cirq_num / 32) * 4);
> + writel_relaxed(mask, mtk_cirq_reg(chip_data, idx, cirq_num));
> }
>
> static void mtk_cirq_mask(struct irq_data *data)
> @@ -160,6 +185,7 @@ static const struct irq_domain_ops cirq_domain_ops = {
> #ifdef CONFIG_PM_SLEEP
> static int mtk_cirq_suspend(void)
> {
> + void __iomem *reg;
> u32 value, mask;
> unsigned int irq, hwirq_num;
> bool pending, masked;
> @@ -200,31 +226,34 @@ static int mtk_cirq_suspend(void)
> continue;
> }
>
> + reg = mtk_cirq_reg(cirq_data, CIRQ_ACK, i);
> mask = 1 << (i % 32);
> - writel_relaxed(mask, cirq_data->base + CIRQ_ACK + (i / 32) * 4);
> + writel_relaxed(mask, reg);
> }
>
> /* set edge_only mode, record edge-triggerd interrupts */
> /* enable cirq */
> - value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> + reg = mtk_cirq_reg(cirq_data, CIRQ_CONTROL, 0);
> + value = readl_relaxed(reg);
> value |= (CIRQ_EDGE | CIRQ_EN);
> - writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
> + writel_relaxed(value, reg);
>
> return 0;
> }
>
> static void mtk_cirq_resume(void)
> {
> + void __iomem *reg = mtk_cirq_reg(cirq_data, CIRQ_CONTROL, 0);
> u32 value;
>
> /* flush recorded interrupts, will send signals to parent controller */
> - value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> - writel_relaxed(value | CIRQ_FLUSH, cirq_data->base + CIRQ_CONTROL);
> + value = readl_relaxed(reg);
> + writel_relaxed(value | CIRQ_FLUSH, reg);
>
> /* disable cirq */
> - value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> + value = readl_relaxed(reg);
> value &= ~(CIRQ_EDGE | CIRQ_EN);
> - writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
> + writel_relaxed(value, reg);
> }
>
> static struct syscore_ops mtk_cirq_syscore_ops = {
> @@ -240,10 +269,18 @@ static void mtk_cirq_syscore_init(void)
> static inline void mtk_cirq_syscore_init(void) {}
> #endif
>
> +static const struct of_device_id mtk_cirq_of_match[] = {

Can't this be made __initconst?

> + { .compatible = "mediatek,mt2701-cirq", .data = &mtk_cirq_regs_v1 },
> + { .compatible = "mediatek,mt8135-cirq", .data = &mtk_cirq_regs_v1 },
> + { .compatible = "mediatek,mt8173-cirq", .data = &mtk_cirq_regs_v1 },
> + { /* sentinel */ }
> +};
> +
> static int __init mtk_cirq_of_init(struct device_node *node,
> struct device_node *parent)
> {
> struct irq_domain *domain, *domain_parent;
> + const struct of_device_id *match;
> unsigned int irq_num;
> int ret;
>
> @@ -274,6 +311,13 @@ static int __init mtk_cirq_of_init(struct device_node *node,
> if (ret)
> goto out_unmap;
>
> + match = of_match_node(mtk_cirq_of_match, node);
> + if (!match) {
> + ret = -ENODEV;
> + goto out_unmap;
> + }

Can't you perform this before mapping the MMIO region and allocating
memory? If you must fail, fail early.

> + cirq_data->offsets = match->data;
> +
> irq_num = cirq_data->ext_irq_end - cirq_data->ext_irq_start + 1;
> domain = irq_domain_add_hierarchy(domain_parent, 0,
> irq_num, node,

M.

--
Without deviation from the norm, progress is not possible.