[v6,1/9] PCI: dwc: Add IRQ chained API support

Adds a IRQ chained API to pcie-designware, that aims to replace the current
IRQ domain hierarchy API implemented.

Although the IRQ domain hierarchy API is still available, pcie-designware
will use now the IRQ chained API.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
---
Change v1->v2:
- num_vectors is now not configurable by the Device Tree. Now it is 32 by
default and can be overridden by any specific SoC driver.
Change v2->v3:
- Nothing changed, just to follow the patch set version.
Change v3->v4:
- Moved Kishon's fixes (PCI end point error and a dra7xx warning) from
v3-0007 patch file to here.
- Undo the change of the function signature to be more coherent with the
host mode specific functions (Thanks Kishon).
- Refactor the added functions in order to used host_data so that getting
pp again back from pci could be avoided. (Thanks Kishon)
- Changed summary line to match the drivers/PCI convention and changelog to
maintain the consistency (thanks Bjorn).
Change v4->v5:
- Implemented Kishon MSI multiple messages fix (thanks Kishon).
Change v5->v6:
- Fixed rebase problem detected by Niklas (thanks Niklas).

 drivers/pci/dwc/pcie-designware-host.c | 296 +++++++++++++++++++++++++++++----
 drivers/pci/dwc/pcie-designware.h      |  18 ++
 2 files changed, 286 insertions(+), 28 deletions(-)

Hi Gustavo,

On 26/01/18 16:35, Gustavo Pimentel wrote:
> Adds a IRQ chained API to pcie-designware, that aims to replace the current
> IRQ domain hierarchy API implemented.
> 
> Although the IRQ domain hierarchy API is still available, pcie-designware
> will use now the IRQ chained API.

I'm a bit thrown by this comment, as I don't think it reflects the
reality of the code.

What you have here is a domain hierarchy (generic PCI MSI layer and HW
specific domain), *and* a multiplexer (chained interrupt) that funnels
all your MSIs into a single parent interrupt. What you're moving away
from is the msi_controller API.

This has no impact on the code, but it helps to use the correct terminology.

> 
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> Tested-by: Niklas Cassel <niklas.cassel@axis.com>
> ---
> Change v1->v2:
> - num_vectors is now not configurable by the Device Tree. Now it is 32 by
> default and can be overridden by any specific SoC driver.
> Change v2->v3:
> - Nothing changed, just to follow the patch set version.
> Change v3->v4:
> - Moved Kishon's fixes (PCI end point error and a dra7xx warning) from
> v3-0007 patch file to here.
> - Undo the change of the function signature to be more coherent with the
> host mode specific functions (Thanks Kishon).
> - Refactor the added functions in order to used host_data so that getting
> pp again back from pci could be avoided. (Thanks Kishon)
> - Changed summary line to match the drivers/PCI convention and changelog to
> maintain the consistency (thanks Bjorn).
> Change v4->v5:
> - Implemented Kishon MSI multiple messages fix (thanks Kishon).
> Change v5->v6:
> - Fixed rebase problem detected by Niklas (thanks Niklas).
> 
>  drivers/pci/dwc/pcie-designware-host.c | 296 +++++++++++++++++++++++++++++----
>  drivers/pci/dwc/pcie-designware.h      |  18 ++
>  2 files changed, 286 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
> index bf558df..f7b2bce 100644
> --- a/drivers/pci/dwc/pcie-designware-host.c
> +++ b/drivers/pci/dwc/pcie-designware-host.c
> @@ -11,6 +11,7 @@
>   * published by the Free Software Foundation.
>   */
>  
> +#include <linux/irqchip/chained_irq.h>
>  #include <linux/irqdomain.h>
>  #include <linux/of_address.h>
>  #include <linux/of_pci.h>
> @@ -53,6 +54,36 @@ static struct irq_chip dw_msi_irq_chip = {
>  	.irq_unmask = pci_msi_unmask_irq,
>  };
>  
> +static void dw_msi_ack_irq(struct irq_data *d)
> +{
> +	irq_chip_ack_parent(d);
> +}
> +
> +static void dw_msi_mask_irq(struct irq_data *d)
> +{
> +	pci_msi_mask_irq(d);
> +	irq_chip_mask_parent(d);
> +}
> +
> +static void dw_msi_unmask_irq(struct irq_data *d)
> +{
> +	pci_msi_unmask_irq(d);
> +	irq_chip_unmask_parent(d);
> +}
> +
> +static struct irq_chip dw_pcie_msi_irq_chip = {
> +	.name = "PCI-MSI",
> +	.irq_ack = dw_msi_ack_irq,
> +	.irq_mask = dw_msi_mask_irq,
> +	.irq_unmask = dw_msi_unmask_irq,
> +};
> +
> +static struct msi_domain_info dw_pcie_msi_domain_info = {
> +	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> +		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
> +	.chip	= &dw_pcie_msi_irq_chip,
> +};
> +
>  /* MSI int handler */
>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  {
> @@ -81,6 +112,196 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  	return ret;
>  }
>  
> +/* Chained MSI interrupt service routine */
> +static void dw_chained_msi_isr(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct pcie_port *pp;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	pp = irq_desc_get_handler_data(desc);
> +	dw_handle_msi_irq(pp);
> +
> +	chained_irq_exit(chip, desc);
> +}

Nit: once you're done with the msi_controller stuff (in patch #8), it'd
be good to move dw_handle_msi_irq() inside this function, as the
irqreturn_t return type doesn't make much sense any more.

> +
> +static void dw_pci_setup_msi_msg(struct irq_data *data, struct msi_msg *msg)
> +{
> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	u64 msi_target;
> +
> +	if (pp->ops->get_msi_addr)
> +		msi_target = pp->ops->get_msi_addr(pp);
> +	else
> +		msi_target = (u64)pp->msi_data;
> +
> +	msg->address_lo = lower_32_bits(msi_target);
> +	msg->address_hi = upper_32_bits(msi_target);
> +
> +	if (pp->ops->get_msi_data)
> +		msg->data = pp->ops->get_msi_data(pp, data->hwirq);
> +	else
> +		msg->data = data->hwirq;
> +
> +	dev_dbg(pci->dev, "msi#%d address_hi %#x address_lo %#x\n",
> +		(int)data->hwirq, msg->address_hi, msg->address_lo);
> +}
> +
> +static int dw_pci_msi_set_affinity(struct irq_data *irq_data,
> +				   const struct cpumask *mask, bool force)
> +{
> +	return -EINVAL;
> +}
> +
> +static void dw_pci_bottom_mask(struct irq_data *data)
> +{
> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
> +	unsigned int res, bit, ctrl;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&pp->lock, flags);

Consider turning this lock (and the corresponding locking primitives) to
a raw spin_lock. This won't have any additional effect for the mainline
kernel, but will make it work correctly if you use the RT patches.

> +
> +	if (pp->ops->msi_clear_irq)
> +		pp->ops->msi_clear_irq(pp, data->hwirq);
> +	else {

Please use { } on both sides of the else.

> +		ctrl = data->hwirq / 32;
> +		res = ctrl * 12;
> +		bit = data->hwirq % 32;
> +
> +		pp->irq_status[ctrl] &= ~(1 << bit);
> +		dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
> +				    pp->irq_status[ctrl]);
> +	}
> +
> +	spin_unlock_irqrestore(&pp->lock, flags);
> +}
> +
> +static void dw_pci_bottom_unmask(struct irq_data *data)
> +{
> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
> +	unsigned int res, bit, ctrl;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&pp->lock, flags);
> +
> +	if (pp->ops->msi_set_irq)
> +		pp->ops->msi_set_irq(pp, data->hwirq);
> +	else {
> +		ctrl = data->hwirq / 32;
> +		res = ctrl * 12;
> +		bit = data->hwirq % 32;
> +
> +		pp->irq_status[ctrl] |= 1 << bit;
> +		dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
> +				    pp->irq_status[ctrl]);
> +	}
> +
> +	spin_unlock_irqrestore(&pp->lock, flags);
> +}
> +
> +static void dw_pci_bottom_ack(struct irq_data *d)
> +{
> +	struct msi_desc *msi = irq_data_get_msi_desc(d);
> +	struct pcie_port *pp;
> +
> +	pp = (struct pcie_port *) msi_desc_to_pci_sysdata(msi);

msi_desc_to_pci_sysdata returns a void*, so you can remove this cast.

> +
> +	if (pp->ops->msi_irq_ack)
> +		pp->ops->msi_irq_ack(d->hwirq, pp);
> +}
> +
> +static struct irq_chip dw_pci_msi_bottom_irq_chip = {
> +	.name = "DWPCI-MSI",
> +	.irq_ack = dw_pci_bottom_ack,
> +	.irq_compose_msi_msg = dw_pci_setup_msi_msg,
> +	.irq_set_affinity = dw_pci_msi_set_affinity,
> +	.irq_mask = dw_pci_bottom_mask,
> +	.irq_unmask = dw_pci_bottom_unmask,
> +};
> +
> +static int dw_pcie_irq_domain_alloc(struct irq_domain *domain,
> +				    unsigned int virq, unsigned int nr_irqs,
> +				    void *args)
> +{
> +	struct pcie_port *pp = domain->host_data;
> +	unsigned long flags;
> +	unsigned long bit;
> +	u32 i;
> +
> +	spin_lock_irqsave(&pp->lock, flags);
> +
> +	bit = bitmap_find_free_region(pp->msi_irq_in_use, pp->num_vectors,
> +				      order_base_2(nr_irqs));
> +
> +	if (bit < 0) {
> +		spin_unlock_irqrestore(&pp->lock, flags);
> +		return -ENOSPC;
> +	}
> +
> +	spin_unlock_irqrestore(&pp->lock, flags);
> +
> +	for (i = 0; i < nr_irqs; i++)
> +		irq_domain_set_info(domain, virq + i, bit + i,
> +				    &dw_pci_msi_bottom_irq_chip,
> +				    pp, handle_level_irq,

Are you sure about this "handle_level_irq"? MSIs are definitely edge
triggered, not level.

> +				    NULL, NULL);
> +
> +	return 0;
> +}
> +
> +static void dw_pcie_irq_domain_free(struct irq_domain *domain,
> +				    unsigned int virq, unsigned int nr_irqs)
> +{
> +	struct irq_data *data = irq_domain_get_irq_data(domain, virq);
> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&pp->lock, flags);
> +	bitmap_release_region(pp->msi_irq_in_use, data->hwirq,
> +			      order_base_2(nr_irqs));
> +	spin_unlock_irqrestore(&pp->lock, flags);
> +}
> +
> +static const struct irq_domain_ops dw_pcie_msi_domain_ops = {
> +	.alloc	= dw_pcie_irq_domain_alloc,
> +	.free	= dw_pcie_irq_domain_free,
> +};
> +
> +int dw_pcie_allocate_domains(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct fwnode_handle *fwnode = of_node_to_fwnode(pci->dev->of_node);
> +
> +	pp->irq_domain = irq_domain_create_linear(fwnode, pp->num_vectors,
> +					       &dw_pcie_msi_domain_ops, pp);
> +	if (!pp->irq_domain) {
> +		dev_err(pci->dev, "failed to create IRQ domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	pp->msi_domain = pci_msi_create_irq_domain(fwnode,
> +						   &dw_pcie_msi_domain_info,
> +						   pp->irq_domain);
> +	if (!pp->msi_domain) {
> +		dev_err(pci->dev, "failed to create MSI domain\n");
> +		irq_domain_remove(pp->irq_domain);
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +void dw_pcie_free_msi(struct pcie_port *pp)
> +{
> +	irq_set_chained_handler(pp->msi_irq, NULL);
> +	irq_set_handler_data(pp->msi_irq, NULL);
> +
> +	irq_domain_remove(pp->msi_domain);
> +	irq_domain_remove(pp->irq_domain);
> +}
> +
>  void dw_pcie_msi_init(struct pcie_port *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> @@ -99,20 +320,21 @@ void dw_pcie_msi_init(struct pcie_port *pp)
>  
>  	/* program the msi_data */
>  	dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4,
> -			    (u32)(msi_target & 0xffffffff));
> +			    lower_32_bits(msi_target));
>  	dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4,
> -			    (u32)(msi_target >> 32 & 0xffffffff));
> +			    upper_32_bits(msi_target));
>  }
>  
>  static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq)
>  {
> -	unsigned int res, bit, val;
> +	unsigned int res, bit, ctrl;
>  
> -	res = (irq / 32) * 12;
> +	ctrl = irq / 32;
> +	res = ctrl * 12;
>  	bit = irq % 32;
> -	dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
> -	val &= ~(1 << bit);
> -	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
> +	pp->irq_status[ctrl] &= ~(1 << bit);
> +	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
> +			    pp->irq_status[ctrl]);
>  }
>  
>  static void clear_irq_range(struct pcie_port *pp, unsigned int irq_base,
> @@ -134,13 +356,14 @@ static void clear_irq_range(struct pcie_port *pp, unsigned int irq_base,
>  
>  static void dw_pcie_msi_set_irq(struct pcie_port *pp, int irq)
>  {
> -	unsigned int res, bit, val;
> +	unsigned int res, bit, ctrl;
>  
> -	res = (irq / 32) * 12;
> +	ctrl = irq / 32;
> +	res = ctrl * 12;
>  	bit = irq % 32;
> -	dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
> -	val |= 1 << bit;
> -	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
> +	pp->irq_status[ctrl] |= 1 << bit;
> +	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
> +			    pp->irq_status[ctrl]);
>  }
>  
>  static int assign_irq(int no_irqs, struct msi_desc *desc, int *pos)
> @@ -288,11 +511,13 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  	struct device *dev = pci->dev;
>  	struct device_node *np = dev->of_node;
>  	struct platform_device *pdev = to_platform_device(dev);
> +	struct resource_entry *win, *tmp;
>  	struct pci_bus *bus, *child;
>  	struct pci_host_bridge *bridge;
>  	struct resource *cfg_res;
> -	int i, ret;
> -	struct resource_entry *win, *tmp;
> +	int ret;
> +
> +	spin_lock_init(&pci->pp.lock);
>  
>  	cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
>  	if (cfg_res) {
> @@ -391,18 +616,33 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  		pci->num_viewport = 2;
>  
>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> -		if (!pp->ops->msi_host_init) {
> -			pp->irq_domain = irq_domain_add_linear(dev->of_node,
> -						MAX_MSI_IRQS, &msi_domain_ops,
> -						&dw_pcie_msi_chip);
> -			if (!pp->irq_domain) {
> -				dev_err(dev, "irq domain init failed\n");
> -				ret = -ENXIO;
> +		/*
> +		 * If a specific SoC driver needs to change the
> +		 * default number of vectors, it needs to implement
> +		 * the set_num_vectors callback.
> +		 */
> +		if (!pp->ops->set_num_vectors) {
> +			pp->num_vectors = MSI_DEF_NUM_VECTORS;
> +		} else {
> +			pp->ops->set_num_vectors(pp);
> +
> +			if (pp->num_vectors > MAX_MSI_IRQS ||
> +			    pp->num_vectors == 0) {
> +				dev_err(dev,
> +					"Invalid number of vectors\n");
>  				goto error;
>  			}
> +		}
>  
> -			for (i = 0; i < MAX_MSI_IRQS; i++)
> -				irq_create_mapping(pp->irq_domain, i);
> +		if (!pp->ops->msi_host_init) {
> +			ret = dw_pcie_allocate_domains(pp);
> +			if (ret)
> +				goto error;
> +
> +			if (pp->msi_irq)
> +				irq_set_chained_handler_and_data(pp->msi_irq,
> +							    dw_chained_msi_isr,
> +							    pp);
>  		} else {
>  			ret = pp->ops->msi_host_init(pp, &dw_pcie_msi_chip);
>  			if (ret < 0)
> @@ -424,10 +664,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  	bridge->ops = &dw_pcie_ops;
>  	bridge->map_irq = of_irq_parse_and_map_pci;
>  	bridge->swizzle_irq = pci_common_swizzle;
> -	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> -		bridge->msi = &dw_pcie_msi_chip;
> -		dw_pcie_msi_chip.dev = dev;
> -	}
>  
>  	ret = pci_scan_root_bus_bridge(bridge);
>  	if (ret)
> @@ -596,11 +832,15 @@ static u8 dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci)
>  
>  void dw_pcie_setup_rc(struct pcie_port *pp)
>  {
> -	u32 val;
> +	u32 val, ctrl;
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  
>  	dw_pcie_setup(pci);
>  
> +	/* Initialize IRQ Status array */
> +	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++)
> +		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + (ctrl * 12), 4,
> +				    &pp->irq_status[ctrl]);
>  	/* setup RC BARs */
>  	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0x00000004);
>  	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000);
> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
> index 8190465..b603e88 100644
> --- a/drivers/pci/dwc/pcie-designware.h
> +++ b/drivers/pci/dwc/pcie-designware.h
> @@ -117,6 +117,7 @@
>   */
>  #define MAX_MSI_IRQS			32
>  #define MAX_MSI_CTRLS			(MAX_MSI_IRQS / 32)
> +#define MSI_DEF_NUM_VECTORS		32
>  
>  /* Maximum number of inbound/outbound iATUs */
>  #define MAX_IATU_IN			256
> @@ -152,7 +153,9 @@ struct dw_pcie_host_ops {
>  	phys_addr_t (*get_msi_addr)(struct pcie_port *pp);
>  	u32 (*get_msi_data)(struct pcie_port *pp, int pos);
>  	void (*scan_bus)(struct pcie_port *pp);
> +	void (*set_num_vectors)(struct pcie_port *pp);
>  	int (*msi_host_init)(struct pcie_port *pp, struct msi_controller *chip);
> +	void (*msi_irq_ack)(int irq, struct pcie_port *pp);
>  };
>  
>  struct pcie_port {
> @@ -177,7 +180,11 @@ struct pcie_port {
>  	const struct dw_pcie_host_ops *ops;
>  	int			msi_irq;
>  	struct irq_domain	*irq_domain;
> +	struct irq_domain	*msi_domain;
>  	dma_addr_t		msi_data;
> +	u32			num_vectors;
> +	u32			irq_status[MAX_MSI_CTRLS];
> +	spinlock_t		lock;
>  	DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
>  };
>  
> @@ -319,8 +326,10 @@ static inline void dw_pcie_dbi_ro_wr_dis(struct dw_pcie *pci)
>  #ifdef CONFIG_PCIE_DW_HOST
>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp);
>  void dw_pcie_msi_init(struct pcie_port *pp);
> +void dw_pcie_free_msi(struct pcie_port *pp);
>  void dw_pcie_setup_rc(struct pcie_port *pp);
>  int dw_pcie_host_init(struct pcie_port *pp);
> +int dw_pcie_allocate_domains(struct pcie_port *pp);
>  #else
>  static inline irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  {
> @@ -331,6 +340,10 @@ static inline void dw_pcie_msi_init(struct pcie_port *pp)
>  {
>  }
>  
> +static inline void dw_pcie_free_msi(struct pcie_port *pp)
> +{
> +}
> +
>  static inline void dw_pcie_setup_rc(struct pcie_port *pp)
>  {
>  }
> @@ -339,6 +352,11 @@ static inline int dw_pcie_host_init(struct pcie_port *pp)
>  {
>  	return 0;
>  }
> +
> +static inline int dw_pcie_allocate_domains(struct pcie_port *pp)
> +{
> +	return 0;
> +}
>  #endif
>  
>  #ifdef CONFIG_PCIE_DW_EP
> 

Thanks,

	M.

Hi Marc,

On 09/02/2018 11:10, Marc Zyngier wrote:
> Hi Gustavo,
> 
> On 26/01/18 16:35, Gustavo Pimentel wrote:
>> Adds a IRQ chained API to pcie-designware, that aims to replace the current
>> IRQ domain hierarchy API implemented.
>>
>> Although the IRQ domain hierarchy API is still available, pcie-designware
>> will use now the IRQ chained API.
> 
> I'm a bit thrown by this comment, as I don't think it reflects the
> reality of the code.
> 
> What you have here is a domain hierarchy (generic PCI MSI layer and HW
> specific domain), *and* a multiplexer (chained interrupt) that funnels
> all your MSIs into a single parent interrupt. What you're moving away
> from is the msi_controller API.
> 
> This has no impact on the code, but it helps to use the correct terminology.
> 

Ok, I'll fix the terminology and descriptions.

>>
>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>> Tested-by: Niklas Cassel <niklas.cassel@axis.com>
>> ---
>> Change v1->v2:
>> - num_vectors is now not configurable by the Device Tree. Now it is 32 by
>> default and can be overridden by any specific SoC driver.
>> Change v2->v3:
>> - Nothing changed, just to follow the patch set version.
>> Change v3->v4:
>> - Moved Kishon's fixes (PCI end point error and a dra7xx warning) from
>> v3-0007 patch file to here.
>> - Undo the change of the function signature to be more coherent with the
>> host mode specific functions (Thanks Kishon).
>> - Refactor the added functions in order to used host_data so that getting
>> pp again back from pci could be avoided. (Thanks Kishon)
>> - Changed summary line to match the drivers/PCI convention and changelog to
>> maintain the consistency (thanks Bjorn).
>> Change v4->v5:
>> - Implemented Kishon MSI multiple messages fix (thanks Kishon).
>> Change v5->v6:
>> - Fixed rebase problem detected by Niklas (thanks Niklas).
>>
>>  drivers/pci/dwc/pcie-designware-host.c | 296 +++++++++++++++++++++++++++++----
>>  drivers/pci/dwc/pcie-designware.h      |  18 ++
>>  2 files changed, 286 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
>> index bf558df..f7b2bce 100644
>> --- a/drivers/pci/dwc/pcie-designware-host.c
>> +++ b/drivers/pci/dwc/pcie-designware-host.c
>> @@ -11,6 +11,7 @@
>>   * published by the Free Software Foundation.
>>   */
>>  
>> +#include <linux/irqchip/chained_irq.h>
>>  #include <linux/irqdomain.h>
>>  #include <linux/of_address.h>
>>  #include <linux/of_pci.h>
>> @@ -53,6 +54,36 @@ static struct irq_chip dw_msi_irq_chip = {
>>  	.irq_unmask = pci_msi_unmask_irq,
>>  };
>>  
>> +static void dw_msi_ack_irq(struct irq_data *d)
>> +{
>> +	irq_chip_ack_parent(d);
>> +}
>> +
>> +static void dw_msi_mask_irq(struct irq_data *d)
>> +{
>> +	pci_msi_mask_irq(d);
>> +	irq_chip_mask_parent(d);
>> +}
>> +
>> +static void dw_msi_unmask_irq(struct irq_data *d)
>> +{
>> +	pci_msi_unmask_irq(d);
>> +	irq_chip_unmask_parent(d);
>> +}
>> +
>> +static struct irq_chip dw_pcie_msi_irq_chip = {
>> +	.name = "PCI-MSI",
>> +	.irq_ack = dw_msi_ack_irq,
>> +	.irq_mask = dw_msi_mask_irq,
>> +	.irq_unmask = dw_msi_unmask_irq,
>> +};
>> +
>> +static struct msi_domain_info dw_pcie_msi_domain_info = {
>> +	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
>> +		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
>> +	.chip	= &dw_pcie_msi_irq_chip,
>> +};
>> +
>>  /* MSI int handler */
>>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>>  {
>> @@ -81,6 +112,196 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>>  	return ret;
>>  }
>>  
>> +/* Chained MSI interrupt service routine */
>> +static void dw_chained_msi_isr(struct irq_desc *desc)
>> +{
>> +	struct irq_chip *chip = irq_desc_get_chip(desc);
>> +	struct pcie_port *pp;
>> +
>> +	chained_irq_enter(chip, desc);
>> +
>> +	pp = irq_desc_get_handler_data(desc);
>> +	dw_handle_msi_irq(pp);
>> +
>> +	chained_irq_exit(chip, desc);
>> +}
> 
> Nit: once you're done with the msi_controller stuff (in patch #8), it'd
> be good to move dw_handle_msi_irq() inside this function, as the
> irqreturn_t return type doesn't make much sense any more.

Hum, I like your suggestion, however there's two drivers (HiSilicon STB and ST
Microelectronics SPEAr13xx) that uses directly the dw_handle_msi_irq function. I
would suggested to this "cleanup" in another patch series, just for keep this
patch simple, if you don't mind.

> 
>> +
>> +static void dw_pci_setup_msi_msg(struct irq_data *data, struct msi_msg *msg)
>> +{
>> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	u64 msi_target;
>> +
>> +	if (pp->ops->get_msi_addr)
>> +		msi_target = pp->ops->get_msi_addr(pp);
>> +	else
>> +		msi_target = (u64)pp->msi_data;
>> +
>> +	msg->address_lo = lower_32_bits(msi_target);
>> +	msg->address_hi = upper_32_bits(msi_target);
>> +
>> +	if (pp->ops->get_msi_data)
>> +		msg->data = pp->ops->get_msi_data(pp, data->hwirq);
>> +	else
>> +		msg->data = data->hwirq;
>> +
>> +	dev_dbg(pci->dev, "msi#%d address_hi %#x address_lo %#x\n",
>> +		(int)data->hwirq, msg->address_hi, msg->address_lo);
>> +}
>> +
>> +static int dw_pci_msi_set_affinity(struct irq_data *irq_data,
>> +				   const struct cpumask *mask, bool force)
>> +{
>> +	return -EINVAL;
>> +}
>> +
>> +static void dw_pci_bottom_mask(struct irq_data *data)
>> +{
>> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
>> +	unsigned int res, bit, ctrl;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&pp->lock, flags);
> 
> Consider turning this lock (and the corresponding locking primitives) to
> a raw spin_lock. This won't have any additional effect for the mainline
> kernel, but will make it work correctly if you use the RT patches.

Ok, I'll do it.

> 
>> +
>> +	if (pp->ops->msi_clear_irq)
>> +		pp->ops->msi_clear_irq(pp, data->hwirq);
>> +	else {
> 
> Please use { } on both sides of the else.

Done.

> 
>> +		ctrl = data->hwirq / 32;
>> +		res = ctrl * 12;
>> +		bit = data->hwirq % 32;
>> +
>> +		pp->irq_status[ctrl] &= ~(1 << bit);
>> +		dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
>> +				    pp->irq_status[ctrl]);
>> +	}
>> +
>> +	spin_unlock_irqrestore(&pp->lock, flags);
>> +}
>> +
>> +static void dw_pci_bottom_unmask(struct irq_data *data)
>> +{
>> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
>> +	unsigned int res, bit, ctrl;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&pp->lock, flags);
>> +
>> +	if (pp->ops->msi_set_irq)
>> +		pp->ops->msi_set_irq(pp, data->hwirq);
>> +	else {
>> +		ctrl = data->hwirq / 32;
>> +		res = ctrl * 12;
>> +		bit = data->hwirq % 32;
>> +
>> +		pp->irq_status[ctrl] |= 1 << bit;
>> +		dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
>> +				    pp->irq_status[ctrl]);
>> +	}
>> +
>> +	spin_unlock_irqrestore(&pp->lock, flags);
>> +}
>> +
>> +static void dw_pci_bottom_ack(struct irq_data *d)
>> +{
>> +	struct msi_desc *msi = irq_data_get_msi_desc(d);
>> +	struct pcie_port *pp;
>> +
>> +	pp = (struct pcie_port *) msi_desc_to_pci_sysdata(msi);
> 
> msi_desc_to_pci_sysdata returns a void*, so you can remove this cast.

Done.

> 
>> +
>> +	if (pp->ops->msi_irq_ack)
>> +		pp->ops->msi_irq_ack(d->hwirq, pp);
>> +}
>> +
>> +static struct irq_chip dw_pci_msi_bottom_irq_chip = {
>> +	.name = "DWPCI-MSI",
>> +	.irq_ack = dw_pci_bottom_ack,
>> +	.irq_compose_msi_msg = dw_pci_setup_msi_msg,
>> +	.irq_set_affinity = dw_pci_msi_set_affinity,
>> +	.irq_mask = dw_pci_bottom_mask,
>> +	.irq_unmask = dw_pci_bottom_unmask,
>> +};
>> +
>> +static int dw_pcie_irq_domain_alloc(struct irq_domain *domain,
>> +				    unsigned int virq, unsigned int nr_irqs,
>> +				    void *args)
>> +{
>> +	struct pcie_port *pp = domain->host_data;
>> +	unsigned long flags;
>> +	unsigned long bit;
>> +	u32 i;
>> +
>> +	spin_lock_irqsave(&pp->lock, flags);
>> +
>> +	bit = bitmap_find_free_region(pp->msi_irq_in_use, pp->num_vectors,
>> +				      order_base_2(nr_irqs));
>> +
>> +	if (bit < 0) {
>> +		spin_unlock_irqrestore(&pp->lock, flags);
>> +		return -ENOSPC;
>> +	}
>> +
>> +	spin_unlock_irqrestore(&pp->lock, flags);
>> +
>> +	for (i = 0; i < nr_irqs; i++)
>> +		irq_domain_set_info(domain, virq + i, bit + i,
>> +				    &dw_pci_msi_bottom_irq_chip,
>> +				    pp, handle_level_irq,
> 
> Are you sure about this "handle_level_irq"? MSIs are definitely edge
> triggered, not level.

Done.

> 
>> +				    NULL, NULL);
>> +
>> +	return 0;
>> +}
>> +
>> +static void dw_pcie_irq_domain_free(struct irq_domain *domain,
>> +				    unsigned int virq, unsigned int nr_irqs)
>> +{
>> +	struct irq_data *data = irq_domain_get_irq_data(domain, virq);
>> +	struct pcie_port *pp = irq_data_get_irq_chip_data(data);
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&pp->lock, flags);
>> +	bitmap_release_region(pp->msi_irq_in_use, data->hwirq,
>> +			      order_base_2(nr_irqs));
>> +	spin_unlock_irqrestore(&pp->lock, flags);
>> +}
>> +
>> +static const struct irq_domain_ops dw_pcie_msi_domain_ops = {
>> +	.alloc	= dw_pcie_irq_domain_alloc,
>> +	.free	= dw_pcie_irq_domain_free,
>> +};
>> +
>> +int dw_pcie_allocate_domains(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct fwnode_handle *fwnode = of_node_to_fwnode(pci->dev->of_node);
>> +
>> +	pp->irq_domain = irq_domain_create_linear(fwnode, pp->num_vectors,
>> +					       &dw_pcie_msi_domain_ops, pp);
>> +	if (!pp->irq_domain) {
>> +		dev_err(pci->dev, "failed to create IRQ domain\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	pp->msi_domain = pci_msi_create_irq_domain(fwnode,
>> +						   &dw_pcie_msi_domain_info,
>> +						   pp->irq_domain);
>> +	if (!pp->msi_domain) {
>> +		dev_err(pci->dev, "failed to create MSI domain\n");
>> +		irq_domain_remove(pp->irq_domain);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +void dw_pcie_free_msi(struct pcie_port *pp)
>> +{
>> +	irq_set_chained_handler(pp->msi_irq, NULL);
>> +	irq_set_handler_data(pp->msi_irq, NULL);
>> +
>> +	irq_domain_remove(pp->msi_domain);
>> +	irq_domain_remove(pp->irq_domain);
>> +}
>> +
>>  void dw_pcie_msi_init(struct pcie_port *pp)
>>  {
>>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> @@ -99,20 +320,21 @@ void dw_pcie_msi_init(struct pcie_port *pp)
>>  
>>  	/* program the msi_data */
>>  	dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4,
>> -			    (u32)(msi_target & 0xffffffff));
>> +			    lower_32_bits(msi_target));
>>  	dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4,
>> -			    (u32)(msi_target >> 32 & 0xffffffff));
>> +			    upper_32_bits(msi_target));
>>  }
>>  
>>  static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq)
>>  {
>> -	unsigned int res, bit, val;
>> +	unsigned int res, bit, ctrl;
>>  
>> -	res = (irq / 32) * 12;
>> +	ctrl = irq / 32;
>> +	res = ctrl * 12;
>>  	bit = irq % 32;
>> -	dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
>> -	val &= ~(1 << bit);
>> -	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
>> +	pp->irq_status[ctrl] &= ~(1 << bit);
>> +	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
>> +			    pp->irq_status[ctrl]);
>>  }
>>  
>>  static void clear_irq_range(struct pcie_port *pp, unsigned int irq_base,
>> @@ -134,13 +356,14 @@ static void clear_irq_range(struct pcie_port *pp, unsigned int irq_base,
>>  
>>  static void dw_pcie_msi_set_irq(struct pcie_port *pp, int irq)
>>  {
>> -	unsigned int res, bit, val;
>> +	unsigned int res, bit, ctrl;
>>  
>> -	res = (irq / 32) * 12;
>> +	ctrl = irq / 32;
>> +	res = ctrl * 12;
>>  	bit = irq % 32;
>> -	dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
>> -	val |= 1 << bit;
>> -	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
>> +	pp->irq_status[ctrl] |= 1 << bit;
>> +	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4,
>> +			    pp->irq_status[ctrl]);
>>  }
>>  
>>  static int assign_irq(int no_irqs, struct msi_desc *desc, int *pos)
>> @@ -288,11 +511,13 @@ int dw_pcie_host_init(struct pcie_port *pp)
>>  	struct device *dev = pci->dev;
>>  	struct device_node *np = dev->of_node;
>>  	struct platform_device *pdev = to_platform_device(dev);
>> +	struct resource_entry *win, *tmp;
>>  	struct pci_bus *bus, *child;
>>  	struct pci_host_bridge *bridge;
>>  	struct resource *cfg_res;
>> -	int i, ret;
>> -	struct resource_entry *win, *tmp;
>> +	int ret;
>> +
>> +	spin_lock_init(&pci->pp.lock);
>>  
>>  	cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
>>  	if (cfg_res) {
>> @@ -391,18 +616,33 @@ int dw_pcie_host_init(struct pcie_port *pp)
>>  		pci->num_viewport = 2;
>>  
>>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> -		if (!pp->ops->msi_host_init) {
>> -			pp->irq_domain = irq_domain_add_linear(dev->of_node,
>> -						MAX_MSI_IRQS, &msi_domain_ops,
>> -						&dw_pcie_msi_chip);
>> -			if (!pp->irq_domain) {
>> -				dev_err(dev, "irq domain init failed\n");
>> -				ret = -ENXIO;
>> +		/*
>> +		 * If a specific SoC driver needs to change the
>> +		 * default number of vectors, it needs to implement
>> +		 * the set_num_vectors callback.
>> +		 */
>> +		if (!pp->ops->set_num_vectors) {
>> +			pp->num_vectors = MSI_DEF_NUM_VECTORS;
>> +		} else {
>> +			pp->ops->set_num_vectors(pp);
>> +
>> +			if (pp->num_vectors > MAX_MSI_IRQS ||
>> +			    pp->num_vectors == 0) {
>> +				dev_err(dev,
>> +					"Invalid number of vectors\n");
>>  				goto error;
>>  			}
>> +		}
>>  
>> -			for (i = 0; i < MAX_MSI_IRQS; i++)
>> -				irq_create_mapping(pp->irq_domain, i);
>> +		if (!pp->ops->msi_host_init) {
>> +			ret = dw_pcie_allocate_domains(pp);
>> +			if (ret)
>> +				goto error;
>> +
>> +			if (pp->msi_irq)
>> +				irq_set_chained_handler_and_data(pp->msi_irq,
>> +							    dw_chained_msi_isr,
>> +							    pp);
>>  		} else {
>>  			ret = pp->ops->msi_host_init(pp, &dw_pcie_msi_chip);
>>  			if (ret < 0)
>> @@ -424,10 +664,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
>>  	bridge->ops = &dw_pcie_ops;
>>  	bridge->map_irq = of_irq_parse_and_map_pci;
>>  	bridge->swizzle_irq = pci_common_swizzle;
>> -	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> -		bridge->msi = &dw_pcie_msi_chip;
>> -		dw_pcie_msi_chip.dev = dev;
>> -	}
>>  
>>  	ret = pci_scan_root_bus_bridge(bridge);
>>  	if (ret)
>> @@ -596,11 +832,15 @@ static u8 dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci)
>>  
>>  void dw_pcie_setup_rc(struct pcie_port *pp)
>>  {
>> -	u32 val;
>> +	u32 val, ctrl;
>>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>>  
>>  	dw_pcie_setup(pci);
>>  
>> +	/* Initialize IRQ Status array */
>> +	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++)
>> +		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + (ctrl * 12), 4,
>> +				    &pp->irq_status[ctrl]);
>>  	/* setup RC BARs */
>>  	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0x00000004);
>>  	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000);
>> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
>> index 8190465..b603e88 100644
>> --- a/drivers/pci/dwc/pcie-designware.h
>> +++ b/drivers/pci/dwc/pcie-designware.h
>> @@ -117,6 +117,7 @@
>>   */
>>  #define MAX_MSI_IRQS			32
>>  #define MAX_MSI_CTRLS			(MAX_MSI_IRQS / 32)
>> +#define MSI_DEF_NUM_VECTORS		32
>>  
>>  /* Maximum number of inbound/outbound iATUs */
>>  #define MAX_IATU_IN			256
>> @@ -152,7 +153,9 @@ struct dw_pcie_host_ops {
>>  	phys_addr_t (*get_msi_addr)(struct pcie_port *pp);
>>  	u32 (*get_msi_data)(struct pcie_port *pp, int pos);
>>  	void (*scan_bus)(struct pcie_port *pp);
>> +	void (*set_num_vectors)(struct pcie_port *pp);
>>  	int (*msi_host_init)(struct pcie_port *pp, struct msi_controller *chip);
>> +	void (*msi_irq_ack)(int irq, struct pcie_port *pp);
>>  };
>>  
>>  struct pcie_port {
>> @@ -177,7 +180,11 @@ struct pcie_port {
>>  	const struct dw_pcie_host_ops *ops;
>>  	int			msi_irq;
>>  	struct irq_domain	*irq_domain;
>> +	struct irq_domain	*msi_domain;
>>  	dma_addr_t		msi_data;
>> +	u32			num_vectors;
>> +	u32			irq_status[MAX_MSI_CTRLS];
>> +	spinlock_t		lock;
>>  	DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
>>  };
>>  
>> @@ -319,8 +326,10 @@ static inline void dw_pcie_dbi_ro_wr_dis(struct dw_pcie *pci)
>>  #ifdef CONFIG_PCIE_DW_HOST
>>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp);
>>  void dw_pcie_msi_init(struct pcie_port *pp);
>> +void dw_pcie_free_msi(struct pcie_port *pp);
>>  void dw_pcie_setup_rc(struct pcie_port *pp);
>>  int dw_pcie_host_init(struct pcie_port *pp);
>> +int dw_pcie_allocate_domains(struct pcie_port *pp);
>>  #else
>>  static inline irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>>  {
>> @@ -331,6 +340,10 @@ static inline void dw_pcie_msi_init(struct pcie_port *pp)
>>  {
>>  }
>>  
>> +static inline void dw_pcie_free_msi(struct pcie_port *pp)
>> +{
>> +}
>> +
>>  static inline void dw_pcie_setup_rc(struct pcie_port *pp)
>>  {
>>  }
>> @@ -339,6 +352,11 @@ static inline int dw_pcie_host_init(struct pcie_port *pp)
>>  {
>>  	return 0;
>>  }
>> +
>> +static inline int dw_pcie_allocate_domains(struct pcie_port *pp)
>> +{
>> +	return 0;
>> +}
>>  #endif
>>  
>>  #ifdef CONFIG_PCIE_DW_EP
>>
> 
> Thanks,
> 
> 	M.
> 

Thanks,
Gustavo

On 12/02/18 17:58, Gustavo Pimentel wrote:
> Hi Marc,
> 
> On 09/02/2018 11:10, Marc Zyngier wrote:
>> Hi Gustavo,
>>
>> On 26/01/18 16:35, Gustavo Pimentel wrote:
>>> Adds a IRQ chained API to pcie-designware, that aims to replace the current
>>> IRQ domain hierarchy API implemented.
>>>
>>> Although the IRQ domain hierarchy API is still available, pcie-designware
>>> will use now the IRQ chained API.
>>
>> I'm a bit thrown by this comment, as I don't think it reflects the
>> reality of the code.
>>
>> What you have here is a domain hierarchy (generic PCI MSI layer and HW
>> specific domain), *and* a multiplexer (chained interrupt) that funnels
>> all your MSIs into a single parent interrupt. What you're moving away
>> from is the msi_controller API.
>>
>> This has no impact on the code, but it helps to use the correct terminology.
>>
> 
> Ok, I'll fix the terminology and descriptions.
> 
>>>
>>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>>> Tested-by: Niklas Cassel <niklas.cassel@axis.com>
>>> ---
>>> Change v1->v2:
>>> - num_vectors is now not configurable by the Device Tree. Now it is 32 by
>>> default and can be overridden by any specific SoC driver.
>>> Change v2->v3:
>>> - Nothing changed, just to follow the patch set version.
>>> Change v3->v4:
>>> - Moved Kishon's fixes (PCI end point error and a dra7xx warning) from
>>> v3-0007 patch file to here.
>>> - Undo the change of the function signature to be more coherent with the
>>> host mode specific functions (Thanks Kishon).
>>> - Refactor the added functions in order to used host_data so that getting
>>> pp again back from pci could be avoided. (Thanks Kishon)
>>> - Changed summary line to match the drivers/PCI convention and changelog to
>>> maintain the consistency (thanks Bjorn).
>>> Change v4->v5:
>>> - Implemented Kishon MSI multiple messages fix (thanks Kishon).
>>> Change v5->v6:
>>> - Fixed rebase problem detected by Niklas (thanks Niklas).
>>>
>>>  drivers/pci/dwc/pcie-designware-host.c | 296 +++++++++++++++++++++++++++++----
>>>  drivers/pci/dwc/pcie-designware.h      |  18 ++
>>>  2 files changed, 286 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
>>> index bf558df..f7b2bce 100644
>>> --- a/drivers/pci/dwc/pcie-designware-host.c
>>> +++ b/drivers/pci/dwc/pcie-designware-host.c
>>> @@ -11,6 +11,7 @@
>>>   * published by the Free Software Foundation.
>>>   */
>>>  
>>> +#include <linux/irqchip/chained_irq.h>
>>>  #include <linux/irqdomain.h>
>>>  #include <linux/of_address.h>
>>>  #include <linux/of_pci.h>
>>> @@ -53,6 +54,36 @@ static struct irq_chip dw_msi_irq_chip = {
>>>  	.irq_unmask = pci_msi_unmask_irq,
>>>  };
>>>  
>>> +static void dw_msi_ack_irq(struct irq_data *d)
>>> +{
>>> +	irq_chip_ack_parent(d);
>>> +}
>>> +
>>> +static void dw_msi_mask_irq(struct irq_data *d)
>>> +{
>>> +	pci_msi_mask_irq(d);
>>> +	irq_chip_mask_parent(d);
>>> +}
>>> +
>>> +static void dw_msi_unmask_irq(struct irq_data *d)
>>> +{
>>> +	pci_msi_unmask_irq(d);
>>> +	irq_chip_unmask_parent(d);
>>> +}
>>> +
>>> +static struct irq_chip dw_pcie_msi_irq_chip = {
>>> +	.name = "PCI-MSI",
>>> +	.irq_ack = dw_msi_ack_irq,
>>> +	.irq_mask = dw_msi_mask_irq,
>>> +	.irq_unmask = dw_msi_unmask_irq,
>>> +};
>>> +
>>> +static struct msi_domain_info dw_pcie_msi_domain_info = {
>>> +	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
>>> +		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
>>> +	.chip	= &dw_pcie_msi_irq_chip,
>>> +};
>>> +
>>>  /* MSI int handler */
>>>  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>>>  {
>>> @@ -81,6 +112,196 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>>>  	return ret;
>>>  }
>>>  
>>> +/* Chained MSI interrupt service routine */
>>> +static void dw_chained_msi_isr(struct irq_desc *desc)
>>> +{
>>> +	struct irq_chip *chip = irq_desc_get_chip(desc);
>>> +	struct pcie_port *pp;
>>> +
>>> +	chained_irq_enter(chip, desc);
>>> +
>>> +	pp = irq_desc_get_handler_data(desc);
>>> +	dw_handle_msi_irq(pp);
>>> +
>>> +	chained_irq_exit(chip, desc);
>>> +}
>>
>> Nit: once you're done with the msi_controller stuff (in patch #8), it'd
>> be good to move dw_handle_msi_irq() inside this function, as the
>> irqreturn_t return type doesn't make much sense any more.
> 
> Hum, I like your suggestion, however there's two drivers (HiSilicon STB and ST
> Microelectronics SPEAr13xx) that uses directly the dw_handle_msi_irq function. I
> would suggested to this "cleanup" in another patch series, just for keep this
> patch simple, if you don't mind.

/me rolls eyes. Holy crap, I didn't notice that. This is terrifying. OK,
let's put that on the list of "things that should not be", and let's
focus on your series.

Thanks,

	M.