[U-Boot] [PATCH 09/10] x86: Access the VGA ROM when needed

[Bin Meng <bmeng.cn@gmail.com>]

Hi Simon,

On Mon, Jan 5, 2015 at 9:45 AM, Simon Glass <sjg@chromium.org> wrote:
> Hi Bin,
>
> On 3 January 2015 at 22:54, Bin Meng <bmeng.cn@gmail.com> wrote:
>> Hi Simon,
>>
>> On Tue, Dec 30, 2014 at 10:32 AM, Simon Glass <sjg@chromium.org> wrote:
>>> Add code to the generic pci_rom file to access the VGA ROM in PCI space
>>> when needed.
>>>
>>> Signed-off-by: Simon Glass <sjg@chromium.org>
>>> ---
>>>
>>>  drivers/pci/pci_auto.c | 28 +++++++++++++++++++++++++++-
>>>  drivers/pci/pci_rom.c  |  7 ++++++-
>>>  include/pci.h          |  9 +++++++++
>>>  3 files changed, 42 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/pci/pci_auto.c b/drivers/pci/pci_auto.c
>>> index 44470fa..61bf6b4 100644
>>> --- a/drivers/pci/pci_auto.c
>>> +++ b/drivers/pci/pci_auto.c
>>> @@ -11,7 +11,7 @@
>>>   */
>>>
>>>  #include <common.h>
>>> -
>>> +#include <errno.h>
>>>  #include <pci.h>
>>>
>>>  #undef DEBUG
>>> @@ -191,6 +191,32 @@ void pciauto_setup_device(struct pci_controller *hose,
>>>         pci_hose_write_config_byte(hose, dev, PCI_LATENCY_TIMER, 0x80);
>>>  }
>>>
>>> +int pciauto_setup_rom(struct pci_controller *hose, pci_dev_t dev)
>>> +{
>>> +       pci_addr_t bar_value;
>>> +       pci_size_t bar_size;
>>> +       u32 bar_response;
>>> +       u16 cmdstat = 0;
>>> +
>>> +       pci_hose_write_config_dword(hose, dev, PCI_ROM_ADDRESS, -2);

I think it is better for people to understand if not writing -2.

>>> +       pci_hose_read_config_dword(hose, dev, PCI_ROM_ADDRESS, &bar_response);
>>> +       if (!bar_response)
>>> +               return -ENOENT;
>>> +
>>> +       bar_size = -(bar_response & ~1);
>>> +       DEBUGF("PCI Autoconfig: ROM, size=%#x, ", bar_size);
>>> +       if (pciauto_region_allocate(hose->pci_mem, bar_size, &bar_value) == 0) {
>>
>> Should we assume pci roms are always mapped using the pci_mem region?
>> If not, maybe we can add another parameter 'region_type' to
>> pciauto_setup_rom()?
>
> I'm not sure - do you think we should support the cacheable area too?
> Would that help?
>

I'm not sure either. I thought you might know more than me as so far I
see pci rom is used for vga, ahci, pxe roms, and storage media for mac
addresses on some ethernet cards. They all belong to pci_mem regions.
Let's do it pci_mem and revisit it in the future if we see something
different.

[snip]

Regards,
Bin