Re: [v8,4/7] PCI: mediatek-gen3: Add INTx support

[Marc Zyngier]

On Wed, 24 Feb 2021 06:11:29 +0000,
Jianjun Wang <jianjun.wang@xxxxxxxxxxxx> wrote:
> 
> Add INTx support for MediaTek Gen3 PCIe controller.
> 
> Signed-off-by: Jianjun Wang <jianjun.wang@xxxxxxxxxxxx>
> Acked-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
> ---
>  drivers/pci/controller/pcie-mediatek-gen3.c | 176 ++++++++++++++++++++
>  1 file changed, 176 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
> index c602beb9afec..8b3b5f838b69 100644
> --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> @@ -9,6 +9,9 @@
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/iopoll.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
> @@ -45,6 +48,13 @@
>  #define PCIE_LINK_STATUS_REG		0x154
>  #define PCIE_PORT_LINKUP		BIT(8)
>  
> +#define PCIE_INT_ENABLE_REG		0x180
> +#define PCIE_INTX_SHIFT			24
> +#define PCIE_INTX_ENABLE \
> +	GENMASK(PCIE_INTX_SHIFT + PCI_NUM_INTX - 1, PCIE_INTX_SHIFT)
> +
> +#define PCIE_INT_STATUS_REG		0x184
> +
>  #define PCIE_TRANS_TABLE_BASE_REG	0x800
>  #define PCIE_ATR_SRC_ADDR_MSB_OFFSET	0x4
>  #define PCIE_ATR_TRSL_ADDR_LSB_OFFSET	0x8
> @@ -73,6 +83,9 @@
>   * @phy: PHY controller block
>   * @clks: PCIe clocks
>   * @num_clks: PCIe clocks count for this port
> + * @irq: PCIe controller interrupt number
> + * @irq_lock: lock protecting IRQ register access
> + * @intx_domain: legacy INTx IRQ domain
>   */
>  struct mtk_pcie_port {
>  	struct device *dev;
> @@ -83,6 +96,10 @@ struct mtk_pcie_port {
>  	struct phy *phy;
>  	struct clk_bulk_data *clks;
>  	int num_clks;
> +
> +	int irq;
> +	raw_spinlock_t irq_lock;
> +	struct irq_domain *intx_domain;
>  };
>  
>  /**
> @@ -199,6 +216,11 @@ static int mtk_pcie_startup_port(struct mtk_pcie_port *port)
>  	val |= PCI_CLASS(PCI_CLASS_BRIDGE_PCI << 8);
>  	writel_relaxed(val, port->base + PCIE_PCI_IDS_1);
>  
> +	/* Mask all INTx interrupts */
> +	val = readl_relaxed(port->base + PCIE_INT_ENABLE_REG);
> +	val &= ~PCIE_INTX_ENABLE;
> +	writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
> +
>  	/* Assert all reset signals */
>  	val = readl_relaxed(port->base + PCIE_RST_CTRL_REG);
>  	val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB;
> @@ -262,6 +284,154 @@ static int mtk_pcie_startup_port(struct mtk_pcie_port *port)
>  	return 0;
>  }
>  
> +static int mtk_pcie_set_affinity(struct irq_data *data,
> +				 const struct cpumask *mask, bool force)
> +{
> +	return -EINVAL;
> +}
> +
> +static void mtk_intx_mask(struct irq_data *data)
> +{
> +	struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
> +	unsigned long flags;
> +	u32 val;
> +
> +	raw_spin_lock_irqsave(&port->irq_lock, flags);
> +	val = readl_relaxed(port->base + PCIE_INT_ENABLE_REG);
> +	val &= ~BIT(data->hwirq + PCIE_INTX_SHIFT);
> +	writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
> +	raw_spin_unlock_irqrestore(&port->irq_lock, flags);
> +}
> +
> +static void mtk_intx_unmask(struct irq_data *data)
> +{
> +	struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
> +	unsigned long flags;
> +	u32 val;
> +
> +	raw_spin_lock_irqsave(&port->irq_lock, flags);
> +	val = readl_relaxed(port->base + PCIE_INT_ENABLE_REG);
> +	val |= BIT(data->hwirq + PCIE_INTX_SHIFT);
> +	writel_relaxed(val, port->base + PCIE_INT_ENABLE_REG);
> +	raw_spin_unlock_irqrestore(&port->irq_lock, flags);
> +}
> +
> +/**
> + * mtk_intx_eoi
> + * @data: pointer to chip specific data
> + *
> + * As an emulated level IRQ, its interrupt status will remain
> + * until the corresponding de-assert message is received; hence that
> + * the status can only be cleared when the interrupt has been serviced.
> + */
> +static void mtk_intx_eoi(struct irq_data *data)
> +{
> +	struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
> +	unsigned long hwirq;
> +
> +	hwirq = data->hwirq + PCIE_INTX_SHIFT;
> +	writel_relaxed(BIT(hwirq), port->base + PCIE_INT_STATUS_REG);
> +}
> +
> +static struct irq_chip mtk_intx_irq_chip = {
> +	.irq_enable		= mtk_intx_unmask,
> +	.irq_disable		= mtk_intx_mask,

Please get rid of enable/disable. Given that you already have
mask/unmask with the *same* implementation, this offers zero benefit.

> +	.irq_mask		= mtk_intx_mask,
> +	.irq_unmask		= mtk_intx_unmask,
> +	.irq_eoi		= mtk_intx_eoi,
> +	.irq_set_affinity	= mtk_pcie_set_affinity,
> +	.name			= "INTx",
> +};

[...]

Other that that, this look good to me.

Thanks,

	M.

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