Re: [net-next] pci_regs.h: Add PCI bus link speed and width defines
From: Bjorn Helgaas
Date: Fri Jan 03 2014 - 17:16:44 EST
On Fri, Jan 3, 2014 at 2:53 PM, Jesse Brandeburg
<jesse.brandeburg@xxxxxxxxx> wrote:
> +linux-pci
Thanks, Jesse.
> <and see note below>
>
> On Thu, Jan 2, 2014 at 4:21 PM, David Miller <davem@xxxxxxxxxxxxx> wrote:
>> From: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
>> Date: Sat, 28 Dec 2013 04:36:13 -0800
>>
>>> Add missing PCI bus link speed 8.0 GT/s and bus link widths of
>>> x1, x2, x4 and x8.
>>>
>>> CC: <linux-kernel@xxxxxxxxxxxxxxx>
>>> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
>>
>> Can a PCI person please ACK this? This is a prerequisite for some
>> networking driver changes Jeff would like to push to me.
The additions look correct to me, and I don't object to them per se, so:
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
However, I do raise my eyebrows a bit at drivers that poke around in
the PCIe capability. I would prefer to have PCI core interfaces that
handle that instead. But I haven't seen Jeff's changes yet.
>>> ---
>>> include/uapi/linux/pci_regs.h | 5 +++++
>>> 1 file changed, 5 insertions(+)
>>>
>>> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
>>> index 4a98e85..c870c2a 100644
>>> --- a/include/uapi/linux/pci_regs.h
>>> +++ b/include/uapi/linux/pci_regs.h
>>> @@ -489,7 +489,12 @@
>>> #define PCI_EXP_LNKSTA_CLS 0x000f /* Current Link Speed */
>>> #define PCI_EXP_LNKSTA_CLS_2_5GB 0x0001 /* Current Link Speed 2.5GT/s */
>>> #define PCI_EXP_LNKSTA_CLS_5_0GB 0x0002 /* Current Link Speed 5.0GT/s */
>>> +#define PCI_EXP_LNKSTA_CLS_8_0GB 0x0003 /* Current Link Speed 8.0GT/s */
>>> #define PCI_EXP_LNKSTA_NLW 0x03f0 /* Negotiated Link Width */
>>> +#define PCI_EXP_LNKSTA_NLW_X1 0x0010 /* Current Link Width x1 */
>>> +#define PCI_EXP_LNKSTA_NLW_X2 0x0020 /* Current Link Width x2 */
>>> +#define PCI_EXP_LNKSTA_NLW_X4 0x0040 /* Current Link Width x4 */
>>> +#define PCI_EXP_LNKSTA_NLW_X8 0x0080 /* Current Link Width x8 */
>>> #define PCI_EXP_LNKSTA_NLW_SHIFT 4 /* start of NLW mask in link status */
>>> #define PCI_EXP_LNKSTA_LT 0x0800 /* Link Training */
>>> #define PCI_EXP_LNKSTA_SLC 0x1000 /* Slot Clock Configuration */
>
> also note that these defines from this patch are already partially
> defined in drivers/pci/probe.c but likely need to move into a header
> file and be consolidated throughout the kernel. That said I don't see
> any issue with adding these as a separate set of defines in
> uapi/linux/pci_regs.h
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