Re: [Patch] PCI:add 32 GT/s decoding in some macros

[Bjorn Helgaas <helgaas@kernel.org>]

On Mon, Jan 13, 2020 at 10:40:20AM +0800, Yicong Yang wrote:
> Link speed 32.0 GT/s is supported in PCIe r5.0. Add in macro
> PCIE_SPEED2STR and PCIE_SPEED2MBS_ENC to correctly decode.
> This patch is a complementary to
> commit de76cda215d5 ("PCI: Decode PCIe 32 GT/s link speed")

Thanks for the patch!  Can you please rework current_link_speed_show()
(which was updated by de76cda215d5 ("PCI: Decode PCIe 32 GT/s link
speed")) so we don't duplicate the strings there and in
PCIE_SPEED2STR()?

Maybe something like:

  switch (linkstat & PCI_EXP_LNKSTA_CLS) {
  case PCI_EXP_LNKSTA_CLS_32_0GB:
    speed = PCIE_SPEED2STR(PCIE_SPEED_32_0GT);
    break;
  ...

My goal is to both remove the string duplication and make it more
likely that when we add the *next* new speed, we'll catch everything
the first time around.

Bjorn

> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> ---
>  drivers/pci/pci.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 3f6947e..2cd64bd 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -288,7 +288,8 @@ void pci_bus_put(struct pci_bus *bus);
> 
>  /* PCIe link information */
>  #define PCIE_SPEED2STR(speed) \
> -	((speed) == PCIE_SPEED_16_0GT ? "16 GT/s" : \
> +	((speed) == PCIE_SPEED_32_0GT ? "32 GT/s" : \
> +	 (speed) == PCIE_SPEED_16_0GT ? "16 GT/s" : \
>  	 (speed) == PCIE_SPEED_8_0GT ? "8 GT/s" : \
>  	 (speed) == PCIE_SPEED_5_0GT ? "5 GT/s" : \
>  	 (speed) == PCIE_SPEED_2_5GT ? "2.5 GT/s" : \
> @@ -296,7 +297,8 @@ void pci_bus_put(struct pci_bus *bus);
> 
>  /* PCIe speed to Mb/s reduced by encoding overhead */
>  #define PCIE_SPEED2MBS_ENC(speed) \
> -	((speed) == PCIE_SPEED_16_0GT ? 16000*128/130 : \
> +	((speed) == PCIE_SPEED_32_0GT ? 32000*128/130 : \
> +	 (speed) == PCIE_SPEED_16_0GT ? 16000*128/130 : \
>  	 (speed) == PCIE_SPEED_8_0GT  ?  8000*128/130 : \
>  	 (speed) == PCIE_SPEED_5_0GT  ?  5000*8/10 : \
>  	 (speed) == PCIE_SPEED_2_5GT  ?  2500*8/10 : \
> --
> 2.8.1
>