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."
And the comment next to the #define says "Register offsets". I don't see
anywhere where it mentions these are CPU addresses. Certainly the
current IORESOURCE_REG users aren't CPU addresses because they're
SPI/I2C device drivers.
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