linux-kernel - Re: [PATCH v7 2/4] PCI: dwc: rockchip: add legacy interrupt support

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Date:   Sat, 16 Apr 2022 13:54:49 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Peter Geis <pgwipeout@...il.com>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Heiko Stuebner <heiko@...ech.de>,
        linux-rockchip@...ts.infradead.org, linux-pci@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/4] PCI: dwc: rockchip: add legacy interrupt support

Peter,

May I suggest that you slow down on the number of versions you send?
This is the 7th in 5 days, the 3rd today.

At this stage, this is entirely counterproductive.

On 2022-04-16 12:05, Peter Geis wrote:
> The legacy interrupts on the rk356x pcie controller are handled by a
> single muxed interrupt. Add irq domain support to the pcie-dw-rockchip
> driver to support the virtual domain.
> 
> Signed-off-by: Peter Geis <pgwipeout@...il.com>
> ---
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 112 +++++++++++++++++-
>  1 file changed, 110 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index c9b341e55cbb..863374604fb1 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -10,9 +10,12 @@
> 
>  #include <linux/clk.h>
>  #include <linux/gpio/consumer.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
>  #include <linux/mfd/syscon.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> +#include <linux/of_irq.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
> @@ -36,10 +39,13 @@
>  #define PCIE_LINKUP			(PCIE_SMLH_LINKUP | PCIE_RDLH_LINKUP)
>  #define PCIE_L0S_ENTRY			0x11
>  #define PCIE_CLIENT_GENERAL_CONTROL	0x0
> +#define PCIE_CLIENT_INTR_STATUS_LEGACY	0x8
> +#define PCIE_CLIENT_INTR_MASK_LEGACY	0x1c
>  #define PCIE_CLIENT_GENERAL_DEBUG	0x104
> -#define PCIE_CLIENT_HOT_RESET_CTRL      0x180
> +#define PCIE_CLIENT_HOT_RESET_CTRL	0x180
>  #define PCIE_CLIENT_LTSSM_STATUS	0x300
> -#define PCIE_LTSSM_ENABLE_ENHANCE       BIT(4)
> +#define PCIE_LEGACY_INT_ENABLE		GENMASK(3, 0)
> +#define PCIE_LTSSM_ENABLE_ENHANCE	BIT(4)
>  #define PCIE_LTSSM_STATUS_MASK		GENMASK(5, 0)
> 
>  struct rockchip_pcie {
> @@ -51,6 +57,8 @@ struct rockchip_pcie {
>  	struct reset_control		*rst;
>  	struct gpio_desc		*rst_gpio;
>  	struct regulator                *vpcie3v3;
> +	struct irq_domain		*irq_domain;
> +	raw_spinlock_t			irq_lock;
>  };
> 
>  static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
> @@ -65,6 +73,94 @@ static void rockchip_pcie_writel_apb(struct
> rockchip_pcie *rockchip,
>  	writel_relaxed(val, rockchip->apb_base + reg);
>  }
> 
> +static void rockchip_pcie_legacy_int_handler(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct rockchip_pcie *rockchip = irq_desc_get_handler_data(desc);
> +	unsigned long reg, hwirq;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	reg = rockchip_pcie_readl_apb(rockchip, 
> PCIE_CLIENT_INTR_STATUS_LEGACY);
> +
> +	for_each_set_bit(hwirq, &reg, 8)

8? And yet:

#define PCI_NUM_INTX        4

So whatever bits are set above bit 3, you are feeding garbage
to the irqdomain code.

> +		generic_handle_domain_irq(rockchip->irq_domain, hwirq);
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static void rockchip_intx_mask(struct irq_data *data)
> +{
> +	struct rockchip_pcie *rockchip = irq_data_get_irq_chip_data(data);
> +	unsigned long flags;
> +	u32 val;
> +
> +	/* disable legacy interrupts */
> +	raw_spin_lock_irqsave(&rockchip->irq_lock, flags);
> +	val = HIWORD_UPDATE_BIT(PCIE_LEGACY_INT_ENABLE);
> +	val |= PCIE_LEGACY_INT_ENABLE;
> +	rockchip_pcie_writel_apb(rockchip, val, 
> PCIE_CLIENT_INTR_MASK_LEGACY);
> +	raw_spin_unlock_irqrestore(&rockchip->irq_lock, flags);

This is completely busted. INTx lines must be controlled individually.
If I disable one device's INTx output, I don't want to see the
interrupt firing because another one has had its own enabled.

         M.
-- 
Jazz is not dead. It just smells funny...