linux-kernel - Re: [PATCH v9 14/20] PCI: microchip: Add get

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Message-ID: <20231025-lizard-prideful-5223384b2c27@spud>
Date:   Wed, 25 Oct 2023 11:44:29 +0100
From:   Conor Dooley <conor@...nel.org>
To:     Minda Chen <minda.chen@...rfivetech.com>
Cc:     Krzysztof Wilczyński <kw@...ux.com>,
        Rob Herring <robh+dt@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Daire McNamara <daire.mcnamara@...rochip.com>,
        Emil Renner Berthing <emil.renner.berthing@...onical.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-pci@...r.kernel.org,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Mason Huo <mason.huo@...rfivetech.com>,
        Leyfoon Tan <leyfoon.tan@...rfivetech.com>,
        Kevin Xie <kevin.xie@...rfivetech.com>
Subject: Re: [PATCH v9 14/20] PCI: microchip: Add get_events() callback
 function

Hey,

On Fri, Oct 20, 2023 at 06:43:35PM +0800, Minda Chen wrote:
> PolarFire implements their own PCIe interrupts,
> which added to global PCIe field for PLDA lack of
> MSI controller, the interrupts to event num mapping
> is different to PLDA local interrupts. So add
> get_events() function pointer.

Just FYI, it's not the PLDA IP's lack of an MSI controller, it's the SoC
itself that doesn't have one. Last time I spoke to Daire about this, he
was surprised that you didn't need something similar. I might reword
this as

"PolarFire SoC implements its own PCIe interrupts, additional to the
regular PCIe interrupts, due to the lack of an MSI controller, so the
interrupt to event number mapping is different to the PLDA local
interrupts, necessitating a custom get_events() implementation."

> Also add struct plda_event_ops function pointer structure
> to struct plda_pcie_rp.

I'd probably also drop this, as it is evident from the diff.

Cheers,
Conor.

> plda_handle_events() will call the get_events() callback
> function pointer directly. For the robustness of codes,
> add checking in plda_init_interrupts().
> 
> Signed-off-by: Minda Chen <minda.chen@...rfivetech.com>
> Acked-by: Conor Dooley <conor.dooley@...rochip.com>
> ---
>  drivers/pci/controller/plda/pcie-microchip-host.c | 14 +++++++++++++-
>  drivers/pci/controller/plda/pcie-plda.h           |  8 ++++++++
>  2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/plda/pcie-microchip-host.c b/drivers/pci/controller/plda/pcie-microchip-host.c
> index e57827bdb4b3..5a8c134bf643 100644
> --- a/drivers/pci/controller/plda/pcie-microchip-host.c
> +++ b/drivers/pci/controller/plda/pcie-microchip-host.c
> @@ -652,7 +652,7 @@ static void plda_handle_event(struct irq_desc *desc)
>  
>  	chained_irq_enter(chip, desc);
>  
> -	events = mc_get_events(port);
> +	events = port->event_ops->get_events(port);
>  
>  	for_each_set_bit(bit, &events, port->num_events)
>  		generic_handle_domain_irq(port->event_domain, bit);
> @@ -811,7 +811,12 @@ static int mc_request_event_irq(struct plda_pcie_rp *plda, int event_irq,
>  				0, event_cause[event].sym, plda);
>  }
>  
> +static const struct plda_event_ops mc_event_ops = {
> +	.get_events = mc_get_events,
> +};
> +
>  static const struct plda_event mc_event = {
> +	.event_ops         = &mc_event_ops,
>  	.request_event_irq = mc_request_event_irq,
>  	.intx_event        = EVENT_LOCAL_PM_MSI_INT_INTX,
>  	.msi_event         = EVENT_LOCAL_PM_MSI_INT_MSI,
> @@ -925,6 +930,11 @@ static int plda_init_interrupts(struct platform_device *pdev,
>  	int i, intx_irq, msi_irq, event_irq;
>  	int ret;
>  
> +	if (!event->event_ops || !event->event_ops->get_events) {
> +		dev_err(dev, "no get events ops\n");
> +		return -EINVAL;
> +	}
> +
>  	ret = plda_pcie_init_irq_domains(port);
>  	if (ret) {
>  		dev_err(dev, "failed creating IRQ domains\n");
> @@ -935,6 +945,8 @@ static int plda_init_interrupts(struct platform_device *pdev,
>  	if (irq < 0)
>  		return -ENODEV;
>  
> +	port->event_ops = event->event_ops;
> +
>  	for (i = 0; i < port->num_events; i++) {
>  		event_irq = irq_create_mapping(port->event_domain, i);
>  		if (!event_irq) {
> diff --git a/drivers/pci/controller/plda/pcie-plda.h b/drivers/pci/controller/plda/pcie-plda.h
> index fba7343f9a96..df1729095952 100644
> --- a/drivers/pci/controller/plda/pcie-plda.h
> +++ b/drivers/pci/controller/plda/pcie-plda.h
> @@ -102,6 +102,12 @@
>  #define EVENT_PM_MSI_INT_SYS_ERR		12
>  #define NUM_PLDA_EVENTS				13
>  
> +struct plda_pcie_rp;
> +
> +struct plda_event_ops {
> +	u32 (*get_events)(struct plda_pcie_rp *pcie);
> +};
> +
>  struct plda_msi {
>  	struct mutex lock;		/* Protect used bitmap */
>  	struct irq_domain *msi_domain;
> @@ -117,11 +123,13 @@ struct plda_pcie_rp {
>  	struct irq_domain *event_domain;
>  	raw_spinlock_t lock;
>  	struct plda_msi msi;
> +	const struct plda_event_ops *event_ops;
>  	void __iomem *bridge_addr;
>  	int num_events;
>  };
>  
>  struct plda_event {
> +	const struct plda_event_ops *event_ops;
>  	int (*request_event_irq)(struct plda_pcie_rp *pcie,
>  				 int event_irq, int event);
>  	int intx_event;
> -- 
> 2.17.1
> 

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