Message-ID: <cd000f57-e01f-e5b9-77f6-baf4e8f45551@arm.com>
Date:   Wed, 23 May 2018 15:23:48 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Andrew Lunn <andrew@...n.ch>,
        Gregory Clement <gregory.clement@...tlin.com>,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Antoine Tenart <antoine.tenart@...tlin.com>,
        Maxime Chevallier <maxime.chevallier@...tlin.com>,
        Nadav Haklai <nadavh@...vell.com>,
        Haim Boot <hayim@...vell.com>, Hanna Hawa <hannah@...vell.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 11/16] irqchip/irq-mvebu-icu: add support for System
 Error Interrupts (SEI)

On 22/05/18 10:40, Miquel Raynal wrote:
> An SEI driver provides an MSI domain through which it is possible to
> raise SEIs.
> 
> Handle the NSR probe function in a more generic way to support other
> type of interrupts (ie. the SEIs).
> 
> For clarity we do not use tree IRQ domains for now but linear ones
> instead, allocating the 207 ICU lines for each interrupt group.

What's the rational for not using trees? Because that's effectively a
100% overhead...

> Reallocating an ICU slot is prevented by the use of an ICU-wide bitmap.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
> ---
>  drivers/irqchip/irq-mvebu-icu.c | 126 ++++++++++++++++++++++++++++++++++------
>  1 file changed, 108 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-mvebu-icu.c b/drivers/irqchip/irq-mvebu-icu.c
> index 977e47b2716f..6ad6236d6ff1 100644
> --- a/drivers/irqchip/irq-mvebu-icu.c
> +++ b/drivers/irqchip/irq-mvebu-icu.c
> @@ -28,6 +28,10 @@
>  #define ICU_SETSPI_NSR_AH	0x14
>  #define ICU_CLRSPI_NSR_AL	0x18
>  #define ICU_CLRSPI_NSR_AH	0x1c
> +#define ICU_SET_SEI_AL		0x50
> +#define ICU_SET_SEI_AH		0x54
> +#define ICU_CLR_SEI_AL		0x58
> +#define ICU_CLR_SEI_AH		0x5C
>  #define ICU_INT_CFG(x)          (0x100 + 4 * (x))
>  #define   ICU_INT_ENABLE	BIT(24)
>  #define   ICU_IS_EDGE		BIT(28)
> @@ -38,12 +42,28 @@
>  #define ICU_SATA0_ICU_ID	109
>  #define ICU_SATA1_ICU_ID	107
>  
> +struct mvebu_icu_subset_data {
> +	unsigned int icu_group;
> +	unsigned int offset_set_ah;
> +	unsigned int offset_set_al;
> +	unsigned int offset_clr_ah;
> +	unsigned int offset_clr_al;
> +};
> +
>  struct mvebu_icu {
>  	struct irq_chip irq_chip;
>  	struct regmap *regmap;
>  	struct device *dev;
> -	atomic_t initialized;
>  	bool legacy_bindings;
> +	/* Lock on interrupt allocations/releases */
> +	spinlock_t msi_lock;
> +	DECLARE_BITMAP(msi_bitmap, ICU_MAX_IRQS);
> +};
> +
> +struct mvebu_icu_msi_data {
> +	struct mvebu_icu *icu;
> +	atomic_t initialized;
> +	const struct mvebu_icu_subset_data *subset_data;
>  };
>  
>  struct mvebu_icu_irq_data {
> @@ -76,16 +96,25 @@ static struct mvebu_icu *mvebu_icu_dev_get_drvdata(struct platform_device *pdev)
>  	return icu;
>  }
>  
> -static void mvebu_icu_init(struct mvebu_icu *icu, struct msi_msg *msg)
> +static void mvebu_icu_init(struct mvebu_icu *icu, struct irq_domain *d,
> +			   struct msi_msg *msg)
>  {
> -	if (atomic_cmpxchg(&icu->initialized, false, true))
> +	struct mvebu_icu_msi_data *msi_data = platform_msi_get_host_data(d);
> +	const struct mvebu_icu_subset_data *subset = msi_data->subset_data;
> +
> +	if (atomic_cmpxchg(&msi_data->initialized, false, true))
> +		return;
> +
> +	/* Set 'SET' ICU SPI message address in AP */
> +	regmap_write(icu->regmap, subset->offset_set_ah, msg[0].address_hi);
> +	regmap_write(icu->regmap, subset->offset_set_al, msg[0].address_lo);
> +
> +	if (subset->icu_group != ICU_GRP_NSR)
>  		return;
>  
> -	/* Set Clear/Set ICU SPI message address in AP */
> -	regmap_write(icu->regmap, ICU_SETSPI_NSR_AH, msg[0].address_hi);
> -	regmap_write(icu->regmap, ICU_SETSPI_NSR_AL, msg[0].address_lo);
> -	regmap_write(icu->regmap, ICU_CLRSPI_NSR_AH, msg[1].address_hi);
> -	regmap_write(icu->regmap, ICU_CLRSPI_NSR_AL, msg[1].address_lo);
> +	/* Set 'CLEAR' ICU SPI message address in AP (level-MSI only) */
> +	regmap_write(icu->regmap, subset->offset_clr_ah, msg[1].address_hi);
> +	regmap_write(icu->regmap, subset->offset_clr_al, msg[1].address_lo);
>  }
>  
>  static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
> @@ -96,8 +125,8 @@ static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
>  	unsigned int icu_int;
>  
>  	if (msg->address_lo || msg->address_hi) {
> -		/* One off initialization */
> -		mvebu_icu_init(icu, msg);
> +		/* One off initialization per domain */
> +		mvebu_icu_init(icu, d->domain, msg);
>  		/* Configure the ICU with irq number & type */
>  		icu_int = msg->data | ICU_INT_ENABLE;
>  		if (icu_irqd->type & IRQ_TYPE_EDGE_RISING)
> @@ -131,7 +160,8 @@ static int
>  mvebu_icu_irq_domain_translate(struct irq_domain *d, struct irq_fwspec *fwspec,
>  			       unsigned long *hwirq, unsigned int *type)
>  {
> -	struct mvebu_icu *icu = platform_msi_get_host_data(d);
> +	struct mvebu_icu_msi_data *msi_data = platform_msi_get_host_data(d);
> +	struct mvebu_icu *icu = msi_data->icu;
>  	unsigned int param_count = icu->legacy_bindings ? 3 : 2;
>  
>  	/* Check the count of the parameters in dt */
> @@ -172,7 +202,9 @@ mvebu_icu_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
>  	int err;
>  	unsigned long hwirq;
>  	struct irq_fwspec *fwspec = args;
> -	struct mvebu_icu *icu = platform_msi_get_host_data(domain);
> +	struct mvebu_icu_msi_data *msi_data =
> +		platform_msi_get_host_data(domain);
> +	struct mvebu_icu *icu = msi_data->icu;
>  	struct mvebu_icu_irq_data *icu_irqd;
>  
>  	icu_irqd = kmalloc(sizeof(*icu_irqd), GFP_KERNEL);
> @@ -186,16 +218,22 @@ mvebu_icu_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
>  		goto free_irqd;
>  	}
>  
> +	spin_lock(&icu->msi_lock);
> +	err = bitmap_allocate_region(icu->msi_bitmap, hwirq, 0);
> +	spin_unlock(&icu->msi_lock);

This (and the freeing counterpart) could deserve a couple of helpers.

> +	if (err < 0)
> +		goto free_irqd;
> +
>  	if (icu->legacy_bindings)
>  		icu_irqd->icu_group = fwspec->param[0];
>  	else
> -		icu_irqd->icu_group = ICU_GRP_NSR;
> +		icu_irqd->icu_group = msi_data->subset_data->icu_group;
>  	icu_irqd->icu = icu;
>  
>  	err = platform_msi_domain_alloc(domain, virq, nr_irqs);
>  	if (err) {
>  		dev_err(icu->dev, "failed to allocate ICU interrupt in parent domain\n");
> -		goto free_irqd;
> +		goto free_bitmap;
>  	}
>  
>  	/* Make sure there is no interrupt left pending by the firmware */
> @@ -214,6 +252,10 @@ mvebu_icu_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
>  
>  free_msi:
>  	platform_msi_domain_free(domain, virq, nr_irqs);
> +free_bitmap:
> +	spin_lock(&icu->msi_lock);
> +	bitmap_release_region(icu->msi_bitmap, hwirq, 0);
> +	spin_unlock(&icu->msi_lock);
>  free_irqd:
>  	kfree(icu_irqd);
>  	return err;
> @@ -223,12 +265,19 @@ static void
>  mvebu_icu_irq_domain_free(struct irq_domain *domain, unsigned int virq,
>  			  unsigned int nr_irqs)
>  {
> +	struct mvebu_icu_msi_data *msi_data =
> +		platform_msi_get_host_data(domain);
> +	struct mvebu_icu *icu = msi_data->icu;
>  	struct irq_data *d = irq_get_irq_data(virq);
>  	struct mvebu_icu_irq_data *icu_irqd = d->chip_data;
>  
>  	kfree(icu_irqd);
>  
>  	platform_msi_domain_free(domain, virq, nr_irqs);
> +
> +	spin_lock(&icu->msi_lock);
> +	bitmap_release_region(icu->msi_bitmap, d->hwirq, 0);
> +	spin_unlock(&icu->msi_lock);
>  }
>  
>  static const struct irq_domain_ops mvebu_icu_domain_ops = {
> @@ -239,14 +288,29 @@ static const struct irq_domain_ops mvebu_icu_domain_ops = {
>  
>  static int mvebu_icu_subset_probe(struct platform_device *pdev)
>  {
> +	const struct mvebu_icu_subset_data *subset;
> +	struct mvebu_icu_msi_data *msi_data;
>  	struct device_node *msi_parent_dn;
>  	struct irq_domain *irq_domain;
>  	struct mvebu_icu *icu;
>  
> +	msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data), GFP_KERNEL);
> +	if (!msi_data)
> +		return -ENOMEM;
> +
>  	icu = mvebu_icu_dev_get_drvdata(pdev);
>  	if (IS_ERR(icu))
>  		return PTR_ERR(icu);
>  
> +	subset = of_device_get_match_data(&pdev->dev);
> +	if (!subset) {
> +		dev_err(&pdev->dev, "Could not retrieve subset data\n");
> +		return -EINVAL;
> +	}
> +
> +	msi_data->icu = icu;
> +	msi_data->subset_data = subset;
> +
>  	pdev->dev.msi_domain = of_msi_get_domain(&pdev->dev, pdev->dev.of_node,
>  						 DOMAIN_BUS_PLATFORM_MSI);
>  	if (!pdev->dev.msi_domain)
> @@ -259,7 +323,7 @@ static int mvebu_icu_subset_probe(struct platform_device *pdev)
>  	irq_domain = platform_msi_create_device_domain(&pdev->dev, ICU_MAX_IRQS,
>  						       mvebu_icu_write_msg,
>  						       &mvebu_icu_domain_ops,
> -						       icu);
> +						       msi_data);
>  	if (!irq_domain) {
>  		dev_err(&pdev->dev, "Failed to create ICU MSI domain\n");
>  		return -ENOMEM;
> @@ -268,9 +332,30 @@ static int mvebu_icu_subset_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct mvebu_icu_subset_data mvebu_icu_nsr_subset_data = {
> +	.icu_group = ICU_GRP_NSR,
> +	.offset_set_ah = ICU_SETSPI_NSR_AH,
> +	.offset_set_al = ICU_SETSPI_NSR_AL,
> +	.offset_clr_ah = ICU_CLRSPI_NSR_AH,
> +	.offset_clr_al = ICU_CLRSPI_NSR_AL,
> +};
> +
> +static const struct mvebu_icu_subset_data mvebu_icu_sei_subset_data = {
> +	.icu_group = ICU_GRP_SEI,
> +	.offset_set_ah = ICU_SET_SEI_AH,
> +	.offset_set_al = ICU_SET_SEI_AL,
> +	.offset_clr_ah = ICU_CLR_SEI_AH,
> +	.offset_clr_al = ICU_CLR_SEI_AL,

I thought SEI was edge only, given what you do in mvebu_icu_init.
Confused...

> +};
> +
>  static const struct of_device_id mvebu_icu_subset_of_match[] = {
>  	{
>  		.compatible = "marvell,cp110-icu-nsr",
> +		.data = &mvebu_icu_nsr_subset_data,
> +	},
> +	{
> +		.compatible = "marvell,cp110-icu-sei",
> +		.data = &mvebu_icu_sei_subset_data,
>  	},
>  	{},
>  };
> @@ -317,6 +402,8 @@ static int mvebu_icu_probe(struct platform_device *pdev)
>  	if (IS_ERR(icu->regmap))
>  		return PTR_ERR(icu->regmap);
>  
> +	spin_lock_init(&icu->msi_lock);
> +
>  	icu->irq_chip.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
>  					    "ICU.%x",
>  					    (unsigned int)res->start);
> @@ -341,7 +428,7 @@ static int mvebu_icu_probe(struct platform_device *pdev)
>  #endif
>  
>  	/*
> -	 * Clean all ICU interrupts with type SPI_NSR, required to
> +	 * Clean all ICU interrupts of type NSR and SEI, required to
>  	 * avoid unpredictable SPI assignments done by firmware.
>  	 */
>  	for (i = 0 ; i < ICU_MAX_IRQS ; i++) {
> @@ -350,7 +437,8 @@ static int mvebu_icu_probe(struct platform_device *pdev)
>  		regmap_read(icu->regmap, ICU_INT_CFG(i), &icu_int);
>  		icu_grp = icu_int >> ICU_GROUP_SHIFT;
>  
> -		if (icu_grp == ICU_GRP_NSR)
> +		if (icu_grp == ICU_GRP_NSR ||
> +		    (icu_grp == ICU_GRP_SEI && !icu->legacy_bindings))
>  			regmap_write(icu->regmap, ICU_INT_CFG(i), 0);
>  	}
>  
> @@ -363,7 +451,9 @@ static int mvebu_icu_probe(struct platform_device *pdev)
>  }
>  
>  static const struct of_device_id mvebu_icu_of_match[] = {
> -	{ .compatible = "marvell,cp110-icu", },
> +	{
> +		.compatible = "marvell,cp110-icu",
> +	},
>  	{},
>  };
>  
> 

Thanks,

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

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