On Mon, 08 Sep 2014 13:22:44 -0700, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> Adding Mark Brown who finished off introducing IORESOURCE_REG.
>
> On 09/08/14 07:52, Grant Likely wrote:
> > On Tue, 2 Sep 2014 18:45:00 +0300, Stanimir Varbanov <svarbanov@xxxxxxxxxx> wrote:
> >> +
> >> unsigned long __weak pci_address_to_pio(phys_addr_t address)
> >> {
> >> if (address > IO_SPACE_LIMIT)
> >> @@ -665,6 +691,29 @@ int of_address_to_resource(struct device_node *dev, int index,
> >> }
> >> EXPORT_SYMBOL_GPL(of_address_to_resource);
> >>
> >> +int of_localbus_address_to_resource(struct device_node *dev, int index,
> >> + struct resource *r)
> >> +{
> >> + const char *name = NULL;
> >> + const __be32 *addrp;
> >> + u64 size;
> >> +
> >> + addrp = of_get_localbus_address(dev, index, &size);
> >> + if (!addrp)
> >> + return -EINVAL;
> >> +
> >> + of_property_read_string_index(dev, "reg-names", index, &name);
> >> +
> >> + memset(r, 0, sizeof(*r));
> >> + r->start = be32_to_cpup(addrp);
> >> + r->end = r->start + size - 1;
> >> + r->flags = IORESOURCE_REG;
> > This is problematic. A resource is created, but there is absolutely no
> > indication that the resource represents a localbus address instead of a
> > CPU address. platform_device reg resources represent CPU addresses.
> > Trying to overload it will cause confusion in drivers.
> >
> >> + r->name = name ? name : dev->full_name;
> >> +
> >> + return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(of_localbus_address_to_resource);
> >> +
> >> struct device_node *of_find_matching_node_by_address(struct device_node *from,
> >> const struct of_device_id *matches,
> >> u64 base_address)
> >> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> >> index 0197725..36dcbd7 100644
> >> --- a/drivers/of/platform.c
> >> +++ b/drivers/of/platform.c
> >> @@ -106,8 +106,9 @@ struct platform_device *of_device_alloc(struct device_node *np,
> >> struct device *parent)
> >> {
> >> struct platform_device *dev;
> >> - int rc, i, num_reg = 0, num_irq;
> >> + int rc, i, num_reg = 0, num_localbus_reg = 0, num_irq;
> >> struct resource *res, temp_res;
> >> + int num_resources;
> >>
> >> dev = platform_device_alloc("", -1);
> >> if (!dev)
> >> @@ -116,22 +117,33 @@ struct platform_device *of_device_alloc(struct device_node *np,
> >> /* count the io and irq resources */
> >> while (of_address_to_resource(np, num_reg, &temp_res) == 0)
> >> num_reg++;
> >> +
> >> + while (of_localbus_address_to_resource(np,
> >> + num_localbus_reg, &temp_res) == 0)
> >> + num_localbus_reg++;
> >> +
> > No, I don't support doing this. The moment a platform_driver depends on
> > a local bus address it is doing something special. It needs to decode
> > its own address in that case, which it can easily do.
> >
> > Any platform_driver that interprets a IORESOURCE_REG as a localbus
> > address instead of a CPU address is *BROKEN*. It should be changed to
> > either decode the address itself, of a new bus type should be created
> > that can make its own decisions about what address resources mean.
>
> Where is this described? From the commit text that introduces
> IORESOURCE_REG I see:
>
> "Currently a bunch of I2C/SPI MFD drivers are using IORESOURCE_IO for
> register address ranges. Since this causes some confusion due to the
> primary use of this resource type for PCI/ISA I/O ports create a new
> resource type IORESOURCE_REG."
Sorry, I mistook IORESOURCE_REG or IORESOURCE_IO. You're right, this
isn't an issue.
I'm still concerned about the implications of automatically populating
platform_devices with this resource type. I'll talk to Mark about it
face to fact at Connect this week.
g.
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