| Message ID | 1442965757-12925-4-git-send-email-ddaney.cavm@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday 22 September 2015 16:49:14 David Daney wrote: > From: David Daney <david.daney@cavium.com> > > The pci-host-generic driver keeps a global struct pci_ops which it > then patches with the .map_bus method appropriate for the bus device. > A problem arises when the driver is used for two different types of > bus devices, the .map_bus method for the last device probed clobbers > the method for all previous devices. The result, only the last bus > device probed has the proper .map_bus, and the others fail. > > Move the struct pci_ops into the bus specific structure, and > initialize it when the bus device is probed. Keep a copy of the > gen_pci_cfg_bus_ops structure, instead of a pointer to a global copy, This is a very useful change. > to future proof against the addition of bus specific elements to > struct pci_ops. but I don't like this part. We should just not have bus specific elements in pci_ops. We don't really have that here either, except that the gen_pci driver had a hack for reusing the same operations for things that are actually different. It's an established practice that anything named '*_operations' is meant to be constant and ideally defined as 'static const ... *_ops;' in the driver. We could try to enforce this better by marking bus->ops as 'const' and changing all the instances of this structure accordingly. > @@ -65,7 +65,11 @@ static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus, > > static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = { > .bus_shift = 16, > - .map_bus = gen_pci_map_cfg_bus_cam, > + .ops = { > + .map_bus = gen_pci_map_cfg_bus_cam, > + .read = pci_generic_config_read, > + .write = pci_generic_config_write, > + } > }; So this is good. We could in theory unify the map_bus functions like this now: static void __iomem *gen_pci_map_cfg_bus(struct pci_bus *bus, unsigned int devfn, int where) { struct gen_pci *pci = bus->sysdata; struct gen_pci_cfg_bus_ops *ops; resource_size_t idx; ops = container_of(bus->ops, struct gen_pci_cfg_bus_ops, ops); idx = bus->number - pci->cfg.bus_range->start; return pci->cfg.win[idx] + ((devfn << ops->dev_shift) | where); } Not sure if that improves clarity or not, up to Will. > @@ -234,8 +237,7 @@ static int gen_pci_probe(struct platform_device *pdev) > } > > of_id = of_match_node(gen_pci_of_match, np); > - pci->cfg.ops = of_id->data; > + pci->cfg.ops = *(struct gen_pci_cfg_bus_ops *)of_id->data; This is the part that grabbed my attention, we should not do it like this. Arnd
On 09/23/2015 01:21 AM, Arnd Bergmann wrote: > On Tuesday 22 September 2015 16:49:14 David Daney wrote: >> From: David Daney <david.daney@cavium.com> >> >> The pci-host-generic driver keeps a global struct pci_ops which it >> then patches with the .map_bus method appropriate for the bus device. >> A problem arises when the driver is used for two different types of >> bus devices, the .map_bus method for the last device probed clobbers >> the method for all previous devices. The result, only the last bus >> device probed has the proper .map_bus, and the others fail. >> >> Move the struct pci_ops into the bus specific structure, and >> initialize it when the bus device is probed. Keep a copy of the >> gen_pci_cfg_bus_ops structure, instead of a pointer to a global copy, > > This is a very useful change. > >> to future proof against the addition of bus specific elements to >> struct pci_ops. > > but I don't like this part. We should just not have bus specific > elements in pci_ops. We don't really have that here either, except > that the gen_pci driver had a hack for reusing the same operations > for things that are actually different. > > It's an established practice that anything named '*_operations' is > meant to be constant and ideally defined as 'static const ... *_ops;' > in the driver. We could try to enforce this better by marking > bus->ops as 'const' and changing all the instances of this structure > accordingly. > >> @@ -65,7 +65,11 @@ static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus, >> >> static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = { >> .bus_shift = 16, >> - .map_bus = gen_pci_map_cfg_bus_cam, >> + .ops = { >> + .map_bus = gen_pci_map_cfg_bus_cam, >> + .read = pci_generic_config_read, >> + .write = pci_generic_config_write, >> + } >> }; > > So this is good. We could in theory unify the map_bus functions > like this now: > > static void __iomem *gen_pci_map_cfg_bus(struct pci_bus *bus, > unsigned int devfn, > int where) > { > struct gen_pci *pci = bus->sysdata; > struct gen_pci_cfg_bus_ops *ops; > resource_size_t idx; > > ops = container_of(bus->ops, struct gen_pci_cfg_bus_ops, ops); > idx = bus->number - pci->cfg.bus_range->start; > > return pci->cfg.win[idx] + ((devfn << ops->dev_shift) | where); > } > > Not sure if that improves clarity or not, up to Will. > >> @@ -234,8 +237,7 @@ static int gen_pci_probe(struct platform_device *pdev) >> } >> >> of_id = of_match_node(gen_pci_of_match, np); >> - pci->cfg.ops = of_id->data; >> + pci->cfg.ops = *(struct gen_pci_cfg_bus_ops *)of_id->data; > > This is the part that grabbed my attention, we should not do it like this. > I will consider changing this so that a structure copy is not used, perhaps as you suggest above. David Daney. > Arnd >
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c index 9e9f1c3..77cf4bd 100644 --- a/drivers/pci/host/pci-host-generic.c +++ b/drivers/pci/host/pci-host-generic.c @@ -27,7 +27,7 @@ struct gen_pci_cfg_bus_ops { u32 bus_shift; - void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int); + struct pci_ops ops; }; struct gen_pci_cfg_windows { @@ -35,7 +35,7 @@ struct gen_pci_cfg_windows { struct resource *bus_range; void __iomem **win; - const struct gen_pci_cfg_bus_ops *ops; + struct gen_pci_cfg_bus_ops ops; }; /* @@ -65,7 +65,11 @@ static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus, static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = { .bus_shift = 16, - .map_bus = gen_pci_map_cfg_bus_cam, + .ops = { + .map_bus = gen_pci_map_cfg_bus_cam, + .read = pci_generic_config_read, + .write = pci_generic_config_write, + } }; static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus, @@ -80,12 +84,11 @@ static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus, static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = { .bus_shift = 20, - .map_bus = gen_pci_map_cfg_bus_ecam, -}; - -static struct pci_ops gen_pci_ops = { - .read = pci_generic_config_read, - .write = pci_generic_config_write, + .ops = { + .map_bus = gen_pci_map_cfg_bus_ecam, + .read = pci_generic_config_read, + .write = pci_generic_config_write, + } }; static const struct of_device_id gen_pci_of_match[] = { @@ -175,7 +178,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) /* Limit the bus-range to fit within reg */ bus_max = pci->cfg.bus_range->start + - (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1; + (resource_size(&pci->cfg.res) >> pci->cfg.ops.bus_shift) - 1; pci->cfg.bus_range->end = min_t(resource_size_t, pci->cfg.bus_range->end, bus_max); @@ -193,7 +196,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) bus_range = pci->cfg.bus_range; for (busn = bus_range->start; busn <= bus_range->end; ++busn) { u32 idx = busn - bus_range->start; - u32 sz = 1 << pci->cfg.ops->bus_shift; + u32 sz = 1 << pci->cfg.ops.bus_shift; pci->cfg.win[idx] = devm_ioremap(dev, pci->cfg.res.start + busn * sz, @@ -234,8 +237,7 @@ static int gen_pci_probe(struct platform_device *pdev) } of_id = of_match_node(gen_pci_of_match, np); - pci->cfg.ops = of_id->data; - gen_pci_ops.map_bus = pci->cfg.ops->map_bus; + pci->cfg.ops = *(struct gen_pci_cfg_bus_ops *)of_id->data; pci->host.dev.parent = dev; INIT_LIST_HEAD(&pci->host.windows); INIT_LIST_HEAD(&pci->resources); @@ -256,7 +258,8 @@ static int gen_pci_probe(struct platform_device *pdev) if (!pci_has_flag(PCI_PROBE_ONLY)) pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS); - bus = pci_scan_root_bus(dev, 0, &gen_pci_ops, pci, &pci->resources); + bus = pci_scan_root_bus(dev, 0, + &pci->cfg.ops.ops, pci, &pci->resources); if (!bus) { dev_err(dev, "Scanning rootbus failed"); return -ENODEV;