Subject: [RFC 2/4] PCI: generic: Add support for ARM64 and MSI(x)

From: [email-masked] (Bjorn Helgaas)
Date: Wed, 5 Nov 2014 16:40:58 -0700

On Thu, Oct 23, 2014 at 03:33:16PM +0200, Arnd Bergmann wrote:
> On Thursday 23 October 2014 10:13:09 Liviu Dudau wrote:
> > > @@ -335,7 +329,9 @@ void __init cns3xxx_pcie_init_late(void)
> > >               cns3xxx_pwr_soft_rst(0x1 << PM_SOFT_RST_REG_OFFST_PCIE(i));
> > >               cns3xxx_pcie_check_link(&cns3xxx_pcie[i]);
> > >               cns3xxx_pcie_hw_init(&cns3xxx_pcie[i]);
> > > -             pci_common_init(&cns3xxx_pcie[i].hw_pci);
> > > +             hw_pci->domain = i;
> > > +             private_data = &cns3xxx_pcie[i];
> > 
> > Is this dance with pointers absolutely necessary? Does gcc though dishes at you
> > for doing hw_pci->private_data = &cns3xxx_pcie[i] directly?
> 
> hw_pci->private_data is an array of pointers to private_data for each
> host controller instance within the domain. There is only one entry
> here, but you still the the correct type, so that would be 
> 
> 	hw_pci->private_data = (void **)&&cns3xxx_pcie[i];
> 
> which is even more confusing and ugly than what I wrote. If you have
> a better idea, I'm all for it. Maybe it's clearer to write like this
> (taken from rcar driver)?
> 
> 	void *hw_private[1];
> 	hw_pci.private_data = hw_private;
> 
> 	for each host {
> 		...
> 		hw_private[0] = &cns3xxx_pcie[i];
> 		pci_common_init_dev(&hw_pci);
> 	}
> 
> Note that all 'modern' controllers always use nr_controllers=1, so we
> only need a single private_data pointer per domain, and the entire
> hw_pci interface is a bit pointless.
> 
> The platforms that currently require it are iop13xx, dove, mv78xx0
> and orion5x. We have plans to remove the last three platforms in
> the next merge window or two, once all users are able to migrate to
> mach-mvebu. Once that happens, we could probably move the entire
> hw_pci logic that deals with multiple hosts per domain into the
> iop13xx pci driver if we want to. A less intrusive simplification
> would be to convert all 'multiplatform'-aware host controllers to
> use pci_common_init_dev() and then take hw_pci out of that.
> 
> See below for a sample patch I just did. It duplicates the code from
> pci_common_init_dev/pci_common_init because we know that all users
> of pci_common_init_dev are modern and only pass a single host bridge.
> The new pci_common_init_dev is simpler than the old one but should
> do the exact same thing for all current users, with the addition
> of propagating the return value.

Same with this one; I'm ignoring for now on the theory that this was just a
sample to show the idea, and a more formal patch might come later.

Bjorn

> pci_init_single() is the new internal helper and we should be able to
> convert all existing users of pci_common_init_dev() to use that directly
> and no longer define hw_pci at all.
> 
> I've converted two drivers to give an example, but the conversions
> should be done in follow-up patches really, and the pci_common_init_dev
> function removed after all users are moved over.
> 
> The new pci_init_single() is also rather simple, and it should just
> converge with what we do for arm64 over time.
> 
> 	Arnd
> 
> ---
>  arch/arm/include/asm/mach/pci.h     |  20 ++++---
>  arch/arm/kernel/bios32.c            | 103 ++++++++++++++++++++++++++++++++++--
>  drivers/pci/host/pci-host-generic.c |  53 ++++++++-----------
>  drivers/pci/host/pci-mvebu.c        |  44 +++++++--------
>  4 files changed, 157 insertions(+), 63 deletions(-)
> 
> diff --git a/arch/arm/include/asm/mach/pci.h b/arch/arm/include/asm/mach/pci.h
> index 7fc42784becb..fe7e13759ec0 100644
> --- a/arch/arm/include/asm/mach/pci.h
> +++ b/arch/arm/include/asm/mach/pci.h
> @@ -73,16 +73,22 @@ struct pci_sys_data {
>  /*
>   * Call this with your hw_pci struct to initialise the PCI system.
>   */
> -void pci_common_init_dev(struct device *, struct hw_pci *);
> +void pci_common_init(struct hw_pci *);
>  
>  /*
> - * Compatibility wrapper for older platforms that do not care about
> - * passing the parent device.
> + * Used by modern platforms, only one host allowed.
>   */
> -static inline void pci_common_init(struct hw_pci *hw)
> -{
> -	pci_common_init_dev(NULL, hw);
> -}
> +int pci_common_init_dev(struct device *, struct hw_pci *);
> +
> +/*
> + * Replaces pci_common_init_dev for drivers that want to do the
> + * initialization simpler and avoid defining hw_pci
> + */
> +int pci_init_single(struct device *parent, 
> +		    struct pci_sys_data *sys,
> +		    struct pci_bus *(*scan)(int nr, struct pci_sys_data *),
> +		    struct pci_ops *ops);
> +
>  
>  /*
>   * Setup early fixed I/O mapping.
> diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
> index 17a26c17f7f5..bccc8703e575 100644
> --- a/arch/arm/kernel/bios32.c
> +++ b/arch/arm/kernel/bios32.c
> @@ -456,8 +456,7 @@ static int pcibios_init_resources(int busnr, struct pci_sys_data *sys)
>  	return 0;
>  }
>  
> -static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
> -			    struct list_head *head)
> +static void pcibios_init_hw(struct hw_pci *hw, struct list_head *head)
>  {
>  	struct pci_sys_data *sys = NULL;
>  	int ret;
> @@ -494,7 +493,7 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
>  			if (hw->scan)
>  				sys->bus = hw->scan(nr, sys);
>  			else
> -				sys->bus = pci_scan_root_bus(parent, sys->busnr,
> +				sys->bus = pci_scan_root_bus(NULL, sys->busnr,
>  						hw->ops, sys, &sys->resources);
>  
>  			if (!sys->bus)
> @@ -511,7 +510,7 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
>  	}
>  }
>  
> -void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
> +void pci_common_init(struct hw_pci *hw)
>  {
>  	struct pci_sys_data *sys;
>  	LIST_HEAD(head);
> @@ -519,7 +518,7 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
>  	pci_add_flags(PCI_REASSIGN_ALL_RSRC);
>  	if (hw->preinit)
>  		hw->preinit();
> -	pcibios_init_hw(parent, hw, &head);
> +	pcibios_init_hw(hw, &head);
>  	if (hw->postinit)
>  		hw->postinit();
>  
> @@ -559,6 +558,100 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
>  	}
>  }
>  
> +int pci_init_single(struct device *parent,
> +		    struct pci_sys_data *sys,
> +		    struct pci_bus *(*scan)(int nr, struct pci_sys_data *),
> +		    struct pci_ops *ops)
> +{
> +	int ret;
> +	struct pci_bus *bus;
> +
> +	ret = pcibios_init_resources(0, sys);
> +	if (ret)
> +		return ret;
> +
> +	if (scan)
> +		bus = scan(0, sys);
> +	else
> +		bus = pci_scan_root_bus(parent, 0, ops, sys, &sys->resources);
> +
> +	if (!bus) {
> +		dev_err(parent, "PCI: unable to scan bus!");
> +		return -ENXIO;
> +	}
> +	sys->bus = bus;
> +
> +	pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
> +
> +	if (!pci_has_flag(PCI_PROBE_ONLY)) {
> +		/*
> +		 * Size the bridge windows.
> +		 */
> +		pci_bus_size_bridges(bus);
> +
> +		/*
> +		 * Assign resources.
> +		 */
> +		pci_bus_assign_resources(bus);
> +	}
> +
> +	/*
> +	 * Tell drivers about devices found.
> +	 */
> +	pci_bus_add_devices(bus);
> +
> +	/* Configure PCI Express settings */
> +	if (bus && !pci_has_flag(PCI_PROBE_ONLY)) {
> +		struct pci_bus *child;
> +
> +		list_for_each_entry(child, &bus->children, node)
> +			pcie_bus_configure_settings(child);
> +	}
> +
> +	return 0;
> +}
> +
> +int pci_common_init_dev(struct device *parent, struct hw_pci *hw)
> +{
> +	struct pci_sys_data *sys;
> +	int ret;
> +
> +	if (hw->nr_controllers != 1 ||
> +	    hw->preinit || hw->postinit)
> +		return -EINVAL;
> +
> +	sys = kzalloc(sizeof(struct pci_sys_data), GFP_KERNEL);
> +	if (!sys)
> +		return -ENOMEM;
> +
> +#ifdef CONFIG_PCI_DOMAINS
> +	sys->domain  = hw->domain;
> +#endif
> +	sys->swizzle = hw->swizzle;
> +	sys->map_irq = hw->map_irq;
> +	sys->align_resource = hw->align_resource;
> +	sys->add_bus = hw->add_bus;
> +	sys->remove_bus = hw->remove_bus;
> +	INIT_LIST_HEAD(&sys->resources);
> +
> +	if (hw->private_data)
> +		sys->private_data = hw->private_data[0];
> +
> +	pci_add_flags(PCI_REASSIGN_ALL_RSRC);
> +	ret = hw->setup(0, sys);
> +	if (ret == 0)
> +		ret = -ENXIO;
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = pcibios_init_sysdata(parent, sys, hw->scan, hw->ops);
> +	if (ret)
> +		/* FIXME: undo ->setup */
> +		kfree(sys);
> +
> +	return ret;
> +}
> +
>  #ifndef CONFIG_PCI_HOST_ITE8152
>  void pcibios_set_master(struct pci_dev *dev)
>  {
> diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
> index 3d2076f59911..3542a7b740e5 100644
> --- a/drivers/pci/host/pci-host-generic.c
> +++ b/drivers/pci/host/pci-host-generic.c
> @@ -40,16 +40,20 @@ struct gen_pci_cfg_windows {
>  
>  struct gen_pci {
>  	struct pci_host_bridge			host;
> +	struct pci_sys_data			sys;
>  	struct gen_pci_cfg_windows		cfg;
> -	struct list_head			resources;
>  };
>  
> +static inline struct gen_pci *gen_pci_from_sys(struct pci_sys_data *sys)
> +{
> +	return container_of(sys, struct gen_pci, sys);
> +}
> +
>  static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
>  					     unsigned int devfn,
>  					     int where)
>  {
> -	struct pci_sys_data *sys = bus->sysdata;
> -	struct gen_pci *pci = sys->private_data;
> +	struct gen_pci *pci = gen_pci_from_sys(bus->sysdata);
>  	resource_size_t idx = bus->number - pci->cfg.bus_range.start;
>  
>  	return pci->cfg.win[idx] + ((devfn << 8) | where);
> @@ -64,8 +68,7 @@ static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
>  					      unsigned int devfn,
>  					      int where)
>  {
> -	struct pci_sys_data *sys = bus->sysdata;
> -	struct gen_pci *pci = sys->private_data;
> +	struct gen_pci *pci = gen_pci_from_sys(bus->sysdata);
>  	resource_size_t idx = bus->number - pci->cfg.bus_range.start;
>  
>  	return pci->cfg.win[idx] + ((devfn << 12) | where);
> @@ -80,8 +83,7 @@ static int gen_pci_config_read(struct pci_bus *bus, unsigned int devfn,
>  				int where, int size, u32 *val)
>  {
>  	void __iomem *addr;
> -	struct pci_sys_data *sys = bus->sysdata;
> -	struct gen_pci *pci = sys->private_data;
> +	struct gen_pci *pci = gen_pci_from_sys(bus->sysdata);
>  
>  	addr = pci->cfg.ops->map_bus(bus, devfn, where);
>  
> @@ -103,8 +105,7 @@ static int gen_pci_config_write(struct pci_bus *bus, unsigned int devfn,
>  				 int where, int size, u32 val)
>  {
>  	void __iomem *addr;
> -	struct pci_sys_data *sys = bus->sysdata;
> -	struct gen_pci *pci = sys->private_data;
> +	struct gen_pci *pci = gen_pci_from_sys(bus->sysdata);
>  
>  	addr = pci->cfg.ops->map_bus(bus, devfn, where);
>  
> @@ -181,10 +182,10 @@ static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
>  {
>  	struct pci_host_bridge_window *win;
>  
> -	list_for_each_entry(win, &pci->resources, list)
> +	list_for_each_entry(win, &pci->sys.resources, list)
>  		release_resource(win->res);
>  
> -	pci_free_resource_list(&pci->resources);
> +	pci_free_resource_list(&pci->sys.resources);
>  }
>  
>  static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
> @@ -237,7 +238,7 @@ static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
>  		if (err)
>  			goto out_release_res;
>  
> -		pci_add_resource_offset(&pci->resources, res, offset);
> +		pci_add_resource_offset(&pci->sys.resources, res, offset);
>  	}
>  
>  	if (!res_valid) {
> @@ -306,17 +307,10 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
>  	}
>  
>  	/* Register bus resource */
> -	pci_add_resource(&pci->resources, bus_range);
> +	pci_add_resource(&pci->sys.resources, bus_range);
>  	return 0;
>  }
>  
> -static int gen_pci_setup(int nr, struct pci_sys_data *sys)
> -{
> -	struct gen_pci *pci = sys->private_data;
> -	list_splice_init(&pci->resources, &sys->resources);
> -	return 1;
> -}
> -
>  static int gen_pci_probe(struct platform_device *pdev)
>  {
>  	int err;
> @@ -326,17 +320,12 @@ static int gen_pci_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct device_node *np = dev->of_node;
>  	struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
> -	struct hw_pci hw = {
> -		.nr_controllers	= 1,
> -		.private_data	= (void **)&pci,
> -		.setup		= gen_pci_setup,
> -		.map_irq	= of_irq_parse_and_map_pci,
> -		.ops		= &gen_pci_ops,
> -	};
>  
>  	if (!pci)
>  		return -ENOMEM;
>  
> +	pci->sys.map_irq	= of_irq_parse_and_map_pci,
> +
>  	type = of_get_property(np, "device_type", NULL);
>  	if (!type || strcmp(type, "pci")) {
>  		dev_err(dev, "invalid \"device_type\" %s\n", type);
> @@ -355,7 +344,7 @@ static int gen_pci_probe(struct platform_device *pdev)
>  	pci->cfg.ops = of_id->data;
>  	pci->host.dev.parent = dev;
>  	INIT_LIST_HEAD(&pci->host.windows);
> -	INIT_LIST_HEAD(&pci->resources);
> +	INIT_LIST_HEAD(&pci->sys.resources);
>  
>  	/* Parse our PCI ranges and request their resources */
>  	err = gen_pci_parse_request_of_pci_ranges(pci);
> @@ -369,8 +358,12 @@ static int gen_pci_probe(struct platform_device *pdev)
>  		return err;
>  	}
>  
> -	pci_common_init_dev(dev, &hw);
> -	return 0;
> +	pci_add_flags(PCI_REASSIGN_ALL_RSRC);
> +	err = pci_init_single(dev, &pci->sys, NULL, &gen_pci_ops);
> +	if (err)
> +		gen_pci_release_of_pci_ranges(pci);
> +
> +	return err;
>  }
>  
>  static struct platform_driver gen_pci_driver = {
> diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
> index b1315e197ffb..e1381c0699be 100644
> --- a/drivers/pci/host/pci-mvebu.c
> +++ b/drivers/pci/host/pci-mvebu.c
> @@ -99,6 +99,7 @@ struct mvebu_pcie_port;
>  struct mvebu_pcie {
>  	struct platform_device *pdev;
>  	struct mvebu_pcie_port *ports;
> +	struct pci_sys_data sysdata;
>  	struct msi_chip *msi;
>  	struct resource io;
>  	char io_name[30];
> @@ -611,7 +612,7 @@ static int mvebu_sw_pci_bridge_write(struct mvebu_pcie_port *port,
>  
>  static inline struct mvebu_pcie *sys_to_pcie(struct pci_sys_data *sys)
>  {
> -	return sys->private_data;
> +	return container_of(sys, struct mvebu_pcie, sysdata);
>  }
>  
>  static struct mvebu_pcie_port *mvebu_pcie_find_port(struct mvebu_pcie *pcie,
> @@ -718,11 +719,26 @@ static struct pci_ops mvebu_pcie_ops = {
>  	.write = mvebu_pcie_wr_conf,
>  };
>  
> -static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
> +/* FIXME: move the code around to avoid these */
> +static struct pci_bus *mvebu_pcie_scan_bus(int nr, struct pci_sys_data *sys);
> +static void mvebu_pcie_add_bus(struct pci_bus *bus);
> +static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
> +						 const struct resource *res,
> +						 resource_size_t start,
> +						 resource_size_t size,
> +						 resource_size_t align);
> +
> +static int mvebu_pcie_enable(struct mvebu_pcie *pcie)
>  {
> -	struct mvebu_pcie *pcie = sys_to_pcie(sys);
>  	int i;
>  	int domain = 0;
> +	struct pci_sys_data *sys = &pcie->sysdata;
> +
> +	pcie->sysdata = (struct pci_sys_data) {
> +		.map_irq        = of_irq_parse_and_map_pci,
> +		.align_resource = mvebu_pcie_align_resource,
> +		.add_bus        = mvebu_pcie_add_bus,
> +	};
>  
>  #ifdef CONFIG_PCI_DOMAINS
>  	domain = sys->domain;
> @@ -738,11 +754,13 @@ static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
>  	if (request_resource(&iomem_resource, &pcie->mem))
>  		return 0;
>  
> +	INIT_LIST_HEAD(&sys->resources);
>  	if (resource_size(&pcie->realio) != 0) {
>  		if (request_resource(&ioport_resource, &pcie->realio)) {
>  			release_resource(&pcie->mem);
>  			return 0;
>  		}
> +
>  		pci_add_resource_offset(&sys->resources, &pcie->realio,
>  					sys->io_offset);
>  	}
> @@ -756,7 +774,9 @@ static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
>  		mvebu_pcie_setup_hw(port);
>  	}
>  
> -	return 1;
> +	pci_add_flags(PCI_REASSIGN_ALL_RSRC);
> +	return pci_init_single(&pcie->pdev->dev, &pcie->sysdata,
> +			       mvebu_pcie_scan_bus, &mvebu_pcie_ops);
>  }
>  
>  static struct pci_bus *mvebu_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> @@ -810,24 +830,6 @@ static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
>  		return start;
>  }
>  
> -static void mvebu_pcie_enable(struct mvebu_pcie *pcie)
> -{
> -	struct hw_pci hw;
> -
> -	memset(&hw, 0, sizeof(hw));
> -
> -	hw.nr_controllers = 1;
> -	hw.private_data   = (void **)&pcie;
> -	hw.setup          = mvebu_pcie_setup;
> -	hw.scan           = mvebu_pcie_scan_bus;
> -	hw.map_irq        = of_irq_parse_and_map_pci;
> -	hw.ops            = &mvebu_pcie_ops;
> -	hw.align_resource = mvebu_pcie_align_resource;
> -	hw.add_bus        = mvebu_pcie_add_bus;
> -
> -	pci_common_init(&hw);
> -}
> -
>  /*
>   * Looks up the list of register addresses encoded into the reg =
>   * <...> property for one that matches the given port/lane. Once
> @@ -1066,9 +1068,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
>  		pci_ioremap_io(i, pcie->io.start + i);
>  
>  	mvebu_pcie_msi_enable(pcie);
> -	mvebu_pcie_enable(pcie);
> -
> -	return 0;
> +	return mvebu_pcie_enable(pcie);
>  }
>  
>  static const struct of_device_id mvebu_pcie_of_match_table[] = {
>