Re: [PATCH V3 06/10] irqchip, GICv3, ITS: Refator ITS dt init code to prepare for ACPI.

[Marc Zyngier]

On 19/01/16 13:11, Tomasz Nowicki wrote:
> Similarly to GICv3 core, we need to extract common code before adding
> ACPI support. No functional changes.
> 
> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> ---
>  drivers/irqchip/irq-gic-v3-its.c   | 82 +++++++++++++++++++++++---------------
>  drivers/irqchip/irq-gic-v3.c       |  6 +--
>  include/linux/irqchip/arm-gic-v3.h |  2 +-
>  3 files changed, 52 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 2bbed18..fecb7a6 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -813,7 +813,7 @@ static void its_free_tables(struct its_node *its)
>  	}
>  }
>  
> -static int its_alloc_tables(const char *node_name, struct its_node *its)
> +static int its_alloc_tables(struct its_node *its)
>  {
>  	int err;
>  	int i;
> @@ -868,8 +868,8 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
>  				    order);
>  			if (order >= MAX_ORDER) {
>  				order = MAX_ORDER - 1;
> -				pr_warn("%s: Device Table too large, reduce its page order to %u\n",
> -					node_name, order);
> +				pr_warn("ITS@0x%lx: Device Table too large, reduce its page order to %u\n",
> +					its->phys_base, order);
>  			}
>  		}
>  
> @@ -878,8 +878,8 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
>  		if (alloc_pages > GITS_BASER_PAGES_MAX) {
>  			alloc_pages = GITS_BASER_PAGES_MAX;
>  			order = get_order(GITS_BASER_PAGES_MAX * psz);
> -			pr_warn("%s: Device Table too large, reduce its page order to %u (%u pages)\n",
> -				node_name, order, alloc_pages);
> +			pr_warn("ITS@0x%lx: Device Table too large, reduce its page order to %u (%u pages)\n",
> +				its->phys_base, order, alloc_pages);
>  		}
>  
>  		base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
> @@ -948,8 +948,8 @@ retry_baser:
>  		}
>  
>  		if (val != tmp) {
> -			pr_err("ITS: %s: GITS_BASER%d doesn't stick: %lx %lx\n",
> -			       node_name, i,
> +			pr_err("ITS@0x%lx: GITS_BASER%d doesn't stick: %lx %lx\n",
> +			       its->phys_base, i,
>  			       (unsigned long) val, (unsigned long) tmp);
>  			err = -ENXIO;
>  			goto out_free;
> @@ -1424,10 +1424,11 @@ static void its_enable_quirks(struct its_node *its)
>  	gic_enable_quirks(iidr, its_quirks, its);
>  }
>  
> -static int __init its_probe(struct device_node *node,
> -			    struct irq_domain *parent)
> +static int __init its_probe_one(phys_addr_t phys_base, unsigned long size,
> +				struct irq_domain *parent,
> +				bool is_msi_controller,

I really question the fact that you are keeping this msi_controller
thing. Let's face it: if this is not an MSI controller, then the whole
thing is absolutely pointless.

So I'd rather you simplify the whole in a separate patch, and just don't
bother initializing the ITS if it cannot be used for MSIs.

> +				struct fwnode_handle *handler)
>  {
> -	struct resource res;
>  	struct its_node *its;
>  	void __iomem *its_base;
>  	struct irq_domain *inner_domain;
> @@ -1435,33 +1436,26 @@ static int __init its_probe(struct device_node *node,
>  	u64 baser, tmp;
>  	int err;
>  
> -	err = of_address_to_resource(node, 0, &res);
> -	if (err) {
> -		pr_warn("%s: no regs?\n", node->full_name);
> -		return -ENXIO;
> -	}
> -
> -	its_base = ioremap(res.start, resource_size(&res));
> +	its_base = ioremap(phys_base, size);
>  	if (!its_base) {
> -		pr_warn("%s: unable to map registers\n", node->full_name);
> +		pr_warn("Unable to map ITS registers\n");

There is some value in at least displaying the base address - think of
people writing their DT or ACPI tables. Please do not blindly remove
debugging information which is often useful on a system with multiple ITS.

>  		return -ENOMEM;
>  	}
>  
>  	val = readl_relaxed(its_base + GITS_PIDR2) & GIC_PIDR2_ARCH_MASK;
>  	if (val != 0x30 && val != 0x40) {
> -		pr_warn("%s: no ITS detected, giving up\n", node->full_name);
> +		pr_warn("No ITS detected, giving up\n");
>  		err = -ENODEV;
>  		goto out_unmap;
>  	}
>  
>  	err = its_force_quiescent(its_base);
>  	if (err) {
> -		pr_warn("%s: failed to quiesce, giving up\n",
> -			node->full_name);
> +		pr_warn("Failed to quiesce, giving up\n");
>  		goto out_unmap;
>  	}
>  
> -	pr_info("ITS: %s\n", node->full_name);
> +	pr_info("ITS@0x%lx\n", (long)phys_base);
>  
>  	its = kzalloc(sizeof(*its), GFP_KERNEL);
>  	if (!its) {
> @@ -1473,7 +1467,7 @@ static int __init its_probe(struct device_node *node,
>  	INIT_LIST_HEAD(&its->entry);
>  	INIT_LIST_HEAD(&its->its_device_list);
>  	its->base = its_base;
> -	its->phys_base = res.start;
> +	its->phys_base = phys_base;
>  	its->ite_size = ((readl_relaxed(its_base + GITS_TYPER) >> 4) & 0xf) + 1;
>  
>  	its->cmd_base = kzalloc(ITS_CMD_QUEUE_SZ, GFP_KERNEL);
> @@ -1485,7 +1479,7 @@ static int __init its_probe(struct device_node *node,
>  
>  	its_enable_quirks(its);
>  
> -	err = its_alloc_tables(node->full_name, its);
> +	err = its_alloc_tables(its);
>  	if (err)
>  		goto out_free_cmd;
>  
> @@ -1521,7 +1515,7 @@ static int __init its_probe(struct device_node *node,
>  	writeq_relaxed(0, its->base + GITS_CWRITER);
>  	writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
>  
> -	if (of_property_read_bool(node, "msi-controller")) {
> +	if (is_msi_controller) {
>  		struct msi_domain_info *info;
>  
>  		info = kzalloc(sizeof(*info), GFP_KERNEL);
> @@ -1530,7 +1524,8 @@ static int __init its_probe(struct device_node *node,
>  			goto out_free_tables;
>  		}
>  
> -		inner_domain = irq_domain_add_tree(node, &its_domain_ops, its);
> +		inner_domain = irq_domain_create_tree(handler, &its_domain_ops,
> +						      its);
>  		if (!inner_domain) {
>  			err = -ENOMEM;
>  			kfree(info);
> @@ -1558,10 +1553,28 @@ out_free_its:
>  	kfree(its);
>  out_unmap:
>  	iounmap(its_base);
> -	pr_err("ITS: failed probing %s (%d)\n", node->full_name, err);
> +	pr_err("ITS@0x%lx: failed probing (%d)\n", (long)phys_base, err);
>  	return err;
>  }
>  
> +static int __init
> +its_of_probe(struct device_node *node, struct irq_domain *parent)
> +{
> +	struct resource res;
> +	bool is_msi_controller = false;
> +
> +	if (of_address_to_resource(node, 0, &res)) {
> +		pr_warn("%s: no regs?\n", node->full_name);
> +		return -ENXIO;
> +	}
> +
> +	if (of_property_read_bool(node, "msi-controller"))
> +		is_msi_controller = true;

This is where you should return early, with a message saying that this
ITS is being ignored if it doesn't have the msi-controller property.

> +
> +	return its_probe_one(res.start, resource_size(&res), parent,
> +			    is_msi_controller, &node->fwnode);
> +}
> +
>  static bool gic_rdists_supports_plpis(void)
>  {
>  	return !!(readl_relaxed(gic_data_rdist_rd_base() + GICR_TYPER) & GICR_TYPER_PLPIS);
> @@ -1586,14 +1599,17 @@ static struct of_device_id its_device_id[] = {
>  	{},
>  };
>  
> -int __init its_init(struct device_node *node, struct rdists *rdists,
> -	     struct irq_domain *parent_domain)
> +int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
> +		    struct irq_domain *parent_domain)
>  {
> -	struct device_node *np;
> +	struct device_node *np, *of_node;
>  
> -	for (np = of_find_matching_node(node, its_device_id); np;
> -	     np = of_find_matching_node(np, its_device_id)) {
> -		its_probe(np, parent_domain);
> +	of_node = to_of_node(handle);
> +	if (of_node) {
> +		for (np = of_find_matching_node(of_node, its_device_id); np;
> +		     np = of_find_matching_node(np, its_device_id)) {
> +			its_of_probe(np, parent_domain);
> +		}
>  	}
>  
>  	if (list_empty(&its_nodes)) {
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index dd16a60..995b7251 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -832,7 +832,6 @@ static int __init gic_init_bases(void __iomem *dist_base,
>  				 u64 redist_stride,
>  				 struct fwnode_handle *handle)
>  {
> -	struct device_node *node;
>  	u32 typer;
>  	int gic_irqs;
>  	int err;
> @@ -872,10 +871,9 @@ static int __init gic_init_bases(void __iomem *dist_base,
>  
>  	set_handle_irq(gic_handle_irq);
>  
> -	node = to_of_node(handle);
>  	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
> -	    node) /* Temp hack to prevent ITS init for ACPI */
> -		its_init(node, &gic_data.rdists, gic_data.domain);
> +	    to_of_node(handle)) /* Temp hack to prevent ITS init for ACPI */
> +		its_init(handle, &gic_data.rdists, gic_data.domain);
>  
>  	gic_smp_init();
>  	gic_dist_init();
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index d5d798b..a40ed7d 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -332,7 +332,7 @@ struct rdists {
>  struct irq_domain;
>  struct device_node;
>  int its_cpu_init(void);
> -int its_init(struct device_node *node, struct rdists *rdists,
> +int its_init(struct fwnode_handle *handle, struct rdists *rdists,
>  	     struct irq_domain *domain);
>  
>  static inline bool gic_enable_sre(void)
> 

Thanks,

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