On Fri, Apr 10, 2015 at 11:12:47AM +0200, Gabriel FERNANDEZ wrote:
> Call directly pci_*() instead of using pci_common_init_dev().
> Enforce error handling in probe.
> It also allows st pcie driver not to declare IO space:
> pci_common_init_dev() is assigning one by default.

Can you verify that none of the other users (dra7xx, exynos, etc.) depends
on the default I/O space, and mention that here?

> Signed-off-by: Fabrice Gasnier <[email protected]>

This requires an ack from Jingoo (DesignWare maintainer), of course.
I think this code is used by dra7xx, exynos, imx6, spear13xx, keystone, and
layerscape.  It'd be nice to have some review and testing from them, too.

> ---
>  drivers/pci/host/pcie-designware.c | 62 
> ++++++++++++++++++++------------------
>  drivers/pci/host/pcie-designware.h |  1 +
>  2 files changed, 33 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/pci/host/pcie-designware.c 
> b/drivers/pci/host/pcie-designware.c
> index 1f4ea6f..d4b1bf7 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -67,8 +67,6 @@
>  #define PCIE_ATU_FUNC(x)             (((x) & 0x7) << 16)
>  #define PCIE_ATU_UPPER_TARGET                0x91C
>  
> -static struct hw_pci dw_pci;
> -
>  static unsigned long global_io_offset;
>  
>  static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
> @@ -342,6 +340,9 @@ static const struct irq_domain_ops msi_domain_ops = {
>       .map = dw_pcie_msi_map,
>  };
>  
> +static int dw_pcie_setup(struct pci_sys_data *sys);
> +static struct pci_bus *dw_pcie_scan_bus(struct pci_sys_data *sys);
> +
>  int __init dw_pcie_host_init(struct pcie_port *pp)
>  {
>       struct device_node *np = pp->dev->of_node;
> @@ -352,6 +353,9 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
>       u32 val, na, ns;
>       const __be32 *addrp;
>       int i, index, ret;
> +     struct list_head *resources = &pp->sysdata.resources;
> +
> +     INIT_LIST_HEAD(resources);
>  
>       /* Find the address cell size and the number of cells in order to get
>        * the untranslated address.
> @@ -504,13 +508,17 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
>  
>  #ifdef CONFIG_PCI_MSI
>       dw_pcie_msi_chip.dev = pp->dev;
> -     dw_pci.msi_ctrl = &dw_pcie_msi_chip;
> +     pp->sysdata.msi_ctrl = &dw_pcie_msi_chip;
>  #endif
>  
> -     dw_pci.nr_controllers = 1;
> -     dw_pci.private_data = (void **)&pp;
> +     pp->sysdata.private_data = pp;
>  
> -     pci_common_init_dev(pp->dev, &dw_pci);
> +     ret = dw_pcie_setup(&pp->sysdata);

It's not completely obvious that replacing pci_common_init_dev() with
dw_pcie_setup() is equivalent.  Here are my notes from trying to convince
myself that this is correct.  I think your changelog could stand some 
enhancement.  It would be ideal if you could break this into a few smaller
patches that were more obviously correct, but I suspect it's too
intertwined to do that.

Here's an outline of pci_common_init_dev():

  pci_common_init_dev(parent, hw)
    pci_add_flags(PCI_REASSIGN_ALL_RSRC)           # [1]
    if (hw->preinit)
      hw->preinit                                  # [2]
    pcibios_init_hw
      for (nr = 0; nr < hw->nr_controllers;        # [3]
          sys = kzalloc                            # [4]
          sys->msi_ctrl = hw->msi_ctrl             # [5]
          sys->busnr = busnr                       # [6]
          sys->swizzle = hw->swizzle               # [7]
          sys->map_irq = hw->map_irq               # [8]
          sys->align_resource = hw->align_resource # [9]
          INIT_LIST_HEAD(&sys->resources)          # [10]
          sys->private_data = hw->private_data     # [11]
          hw->setup                                # [12]
          pcibios_init_resources                   # [13]
          hw->scan                                 # [14]
    if (hw->postinit)
      hw->postinit                                 # [15]
    pci_fixup_irqs                                 # [16]
    list_for_each_entry(sys, &head,                # [17]
      if (!pci_has_flag(PCI_PROBE_ONLY))           # [18]
        pci_bus_size_bridges                       # [19]
        pci_bus_assign_resources
      pci_bus_add_devices
    list_for_each_entry(sys, &head,
      ...
        pcie_bus_configure_settings                # [20]

[1] You don't set PCI_REASSIGN_ALL_RSRC; have you verified that nobody
cares about that?

[2] dw_pci.preinit was NULL, so skipping this doesn't matter; looks OK.

[3] dw_pci.nr_controllers was always 1, so skipping the loop doesn't
matter; looks OK.

[4] You added struct pci_sys_data sysdata as a member of struct
pcie_port, so it is now allocated by dw_pcie_host_init() callers, e.g.,
st_pcie_probe(); looks OK.

[5] You set pp->sysdata.msi_ctrl in dw_pcie_host_init() instead of
pcibios_init_hw(); looks OK. 

[6] Since dw_pci.nr_controllers was always 1, sys->busnr was always 0.
You don't set sys->busnr, so it will retain its initial zero value.  OK, I
guess.  It's still a little broken that we have both pp->busn and
pp->sysdata.busnr, but you didn't break it and it's OK that you didn't
change anything in this regard.

[7] dw_pci.swizzle was NULL, so pcibios_swizzle() would default to
pci_common_swizzle(), which is what you use when you call pci_fixup_irqs()
in dw_pcie_scan_bus(); looks OK.

[8] dw_pci.map_irq was dw_pcie_map_irq() (which used
of_irq_parse_and_map_pci()) and sys->map_irq was used by pcibios_map_irq().
You call pci_fixup_irqs() and pass a pointer to of_irq_parse_and_map_pci();
looks OK.

[9] dw_pci.align_resource was NULL, and I assume
pcie_port.sysdata.align_resource was initialized to zeroes; looks OK.

[10] You call INIT_LIST_HEAD() in dw_pcie_host_init() instead of
pcibios_init_hw(); looks OK.

[11] You set sys->private_data in dw_pcie_host_init() instead of
pcibios_init_hw(); looks OK.

[12] dw_pci.setup was dw_pcie_setup(), and you call that from
dw_pcie_host_init(); looks OK.

[13] You no longer call pcibios_init_resources().  You don't want the
default I/O space, which makes sense; looks OK (but you need to audit other
users and make sure they don't need it either).

[14] dw_pci.scan was dw_pcie_scan_bus(), and you call that from
dw_pcie_host_init(); looks OK.

[15] dw_pci.postinit was NULL, so skipping this doesn't matter; looks OK.

[16] You call pci_fixup_irqs() from dw_pcie_scan_bus() instead of
pci_common_init_dev(); looks OK.

[17] "head" is a local list in pci_common_init_dev(), and you don't need
anything similar because dw_pcie_host_init() is called once per host
bridge; looks OK.

[18] You don't test PCI_PROBE_ONLY; it looks like it can still be set by
booting with "pci=firmware".  So previously, "pci=firmware" prevented
resource assignment, but it no longer does.  Is that right?  Is that what
you intend?

[19] Instead of pci_bus_size_bridges() and pci_bus_assign_resources(), you
call pci_assign_unassigned_bus_resources() from dw_pcie_scan_bus().  That
seems like an improvement because it holds pci_bus_sem and supplies
add_list; looks OK.

[20] I think you no longer call pcie_bus_configure_settings().  That
configured MPS settings, and I think you still want to do that, don't you?

> +     if (ret)
> +             return ret;
> +
> +     if (!dw_pcie_scan_bus(&pp->sysdata))
> +             return -ENXIO;
>  
>       return 0;
>  }
> @@ -701,15 +709,19 @@ static struct pci_ops dw_pcie_ops = {
>       .write = dw_pcie_wr_conf,
>  };
>  
> -static int dw_pcie_setup(int nr, struct pci_sys_data *sys)
> +static int dw_pcie_setup(struct pci_sys_data *sys)
>  {
>       struct pcie_port *pp;
> +     int err;
>  
>       pp = sys_to_pcie(sys);
>  
>       if (global_io_offset < SZ_1M && pp->io_size > 0) {
>               sys->io_offset = global_io_offset - pp->io_bus_addr;
> -             pci_ioremap_io(global_io_offset, pp->io_base);
> +             err = pci_ioremap_io(global_io_offset, pp->io_base);
> +             if (err)
> +                     return err;
> +
>               global_io_offset += SZ_64K;
>               pci_add_resource_offset(&sys->resources, &pp->io,
>                                       sys->io_offset);
> @@ -719,10 +731,10 @@ static int dw_pcie_setup(int nr, struct pci_sys_data 
> *sys)
>       pci_add_resource_offset(&sys->resources, &pp->mem, sys->mem_offset);
>       pci_add_resource(&sys->resources, &pp->busn);
>  
> -     return 1;
> +     return 0;
>  }
>  
> -static struct pci_bus *dw_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> +static struct pci_bus *dw_pcie_scan_bus(struct pci_sys_data *sys)
>  {
>       struct pci_bus *bus;
>       struct pcie_port *pp = sys_to_pcie(sys);
> @@ -738,27 +750,13 @@ static struct pci_bus *dw_pcie_scan_bus(int nr, struct 
> pci_sys_data *sys)
>       if (bus && pp->ops->scan_bus)
>               pp->ops->scan_bus(pp);
>  
> -     return bus;
> -}
> -
> -static int dw_pcie_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
> -{
> -     struct pcie_port *pp = sys_to_pcie(dev->bus->sysdata);
> -     int irq;
> -
> -     irq = of_irq_parse_and_map_pci(dev, slot, pin);
> -     if (!irq)
> -             irq = pp->irq;
> +     pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
> +     pci_assign_unassigned_bus_resources(bus);
> +     pci_bus_add_devices(bus);
>  
> -     return irq;
> +     return bus;
>  }
>  
> -static struct hw_pci dw_pci = {
> -     .setup          = dw_pcie_setup,
> -     .scan           = dw_pcie_scan_bus,
> -     .map_irq        = dw_pcie_map_irq,
> -};
> -
>  void dw_pcie_setup_rc(struct pcie_port *pp)
>  {
>       u32 val;
> @@ -822,8 +820,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
>       /* setup command register */
>       dw_pcie_readl_rc(pp, PCI_COMMAND, &val);
>       val &= 0xffff0000;
> -     val |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
> -             PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
> +
> +     if (!pp->io_size)
> +             val |= PCI_COMMAND_IO;
> +
> +     val |= PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
> +
>       dw_pcie_writel_rc(pp, val, PCI_COMMAND);
>  }
>  
> diff --git a/drivers/pci/host/pcie-designware.h 
> b/drivers/pci/host/pcie-designware.h
> index d0bbd27..45bc2c2 100644
> --- a/drivers/pci/host/pcie-designware.h
> +++ b/drivers/pci/host/pcie-designware.h
> @@ -46,6 +46,7 @@ struct pcie_port {
>       struct resource         io;
>       struct resource         mem;
>       struct resource         busn;
> +     struct pci_sys_data     sysdata;
>       int                     irq;
>       u32                     lanes;
>       struct pcie_host_ops    *ops;
> -- 
> 1.9.1
> 
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