Re: [PATCH] PCI: Decode PCIe 64 GT/s link speed

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Nov 18, 2020 at 11:49:20PM +0100, Gustavo Pimentel wrote:
> PCIe r6.0, sec 7.5.3.18, defines a new 64.0 GT/s bit in the Supported
> Link Speeds Vector of Link Capabilities 2.
> 
> This does not affect the speed of the link, which should be negotiated
> automatically by the hardware; it only adds decoding when showing the
> speed to the user.
> 
> This patch adds the decoding of this new speed, previously, reading the
> speed of a link operating at this speed showed "Unknown speed" instead
> of "64.0 GT/s".
> 
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

Applied with Krzysztof's reviewed-by to pci/enumeration for v5.11,
thanks!

> ---
>  drivers/pci/pci.h             | 6 ++++--
>  drivers/pci/probe.c           | 3 ++-
>  include/linux/pci.h           | 1 +
>  include/uapi/linux/pci_regs.h | 4 ++++
>  4 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index f86cae9..81bf905 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -294,7 +294,8 @@ void pci_bus_put(struct pci_bus *bus);
>  
>  /* PCIe link information from Link Capabilities 2 */
>  #define PCIE_LNKCAP2_SLS2SPEED(lnkcap2) \
> -	((lnkcap2) & PCI_EXP_LNKCAP2_SLS_32_0GB ? PCIE_SPEED_32_0GT : \
> +	((lnkcap2) & PCI_EXP_LNKCAP2_SLS_64_0GB ? PCIE_SPEED_64_0GT : \
> +	 (lnkcap2) & PCI_EXP_LNKCAP2_SLS_32_0GB ? PCIE_SPEED_32_0GT : \
>  	 (lnkcap2) & PCI_EXP_LNKCAP2_SLS_16_0GB ? PCIE_SPEED_16_0GT : \
>  	 (lnkcap2) & PCI_EXP_LNKCAP2_SLS_8_0GB ? PCIE_SPEED_8_0GT : \
>  	 (lnkcap2) & PCI_EXP_LNKCAP2_SLS_5_0GB ? PCIE_SPEED_5_0GT : \
> @@ -303,7 +304,8 @@ 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_32_0GT ? 32000*128/130 : \
> +	((speed) == PCIE_SPEED_64_0GT ? 64000*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 : \
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 4289030..fe2e00f 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -677,7 +677,7 @@ const unsigned char pcie_link_speed[] = {
>  	PCIE_SPEED_8_0GT,		/* 3 */
>  	PCIE_SPEED_16_0GT,		/* 4 */
>  	PCIE_SPEED_32_0GT,		/* 5 */
> -	PCI_SPEED_UNKNOWN,		/* 6 */
> +	PCIE_SPEED_64_0GT,		/* 6 */
>  	PCI_SPEED_UNKNOWN,		/* 7 */
>  	PCI_SPEED_UNKNOWN,		/* 8 */
>  	PCI_SPEED_UNKNOWN,		/* 9 */
> @@ -719,6 +719,7 @@ const char *pci_speed_string(enum pci_bus_speed speed)
>  	    "8.0 GT/s PCIe",		/* 0x16 */
>  	    "16.0 GT/s PCIe",		/* 0x17 */
>  	    "32.0 GT/s PCIe",		/* 0x18 */
> +	    "64.0 GT/s PCIe",		/* 0x19 */
>  	};
>  
>  	if (speed < ARRAY_SIZE(speed_strings))
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 22207a7..e007bc3 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -281,6 +281,7 @@ enum pci_bus_speed {
>  	PCIE_SPEED_8_0GT		= 0x16,
>  	PCIE_SPEED_16_0GT		= 0x17,
>  	PCIE_SPEED_32_0GT		= 0x18,
> +	PCIE_SPEED_64_0GT		= 0x19,
>  	PCI_SPEED_UNKNOWN		= 0xff,
>  };
>  
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index a95d55f..fe9d5db 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -531,6 +531,7 @@
>  #define  PCI_EXP_LNKCAP_SLS_8_0GB 0x00000003 /* LNKCAP2 SLS Vector bit 2 */
>  #define  PCI_EXP_LNKCAP_SLS_16_0GB 0x00000004 /* LNKCAP2 SLS Vector bit 3 */
>  #define  PCI_EXP_LNKCAP_SLS_32_0GB 0x00000005 /* LNKCAP2 SLS Vector bit 4 */
> +#define  PCI_EXP_LNKCAP_SLS_64_0GB 0x00000006 /* LNKCAP2 SLS Vector bit 5 */
>  #define  PCI_EXP_LNKCAP_MLW	0x000003f0 /* Maximum Link Width */
>  #define  PCI_EXP_LNKCAP_ASPMS	0x00000c00 /* ASPM Support */
>  #define  PCI_EXP_LNKCAP_ASPM_L0S 0x00000400 /* ASPM L0s Support */
> @@ -562,6 +563,7 @@
>  #define  PCI_EXP_LNKSTA_CLS_8_0GB 0x0003 /* Current Link Speed 8.0GT/s */
>  #define  PCI_EXP_LNKSTA_CLS_16_0GB 0x0004 /* Current Link Speed 16.0GT/s */
>  #define  PCI_EXP_LNKSTA_CLS_32_0GB 0x0005 /* Current Link Speed 32.0GT/s */
> +#define  PCI_EXP_LNKSTA_CLS_64_0GB 0x0006 /* Current Link Speed 64.0GT/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 */
> @@ -670,6 +672,7 @@
>  #define  PCI_EXP_LNKCAP2_SLS_8_0GB	0x00000008 /* Supported Speed 8GT/s */
>  #define  PCI_EXP_LNKCAP2_SLS_16_0GB	0x00000010 /* Supported Speed 16GT/s */
>  #define  PCI_EXP_LNKCAP2_SLS_32_0GB	0x00000020 /* Supported Speed 32GT/s */
> +#define  PCI_EXP_LNKCAP2_SLS_64_0GB	0x00000040 /* Supported Speed 64GT/s */
>  #define  PCI_EXP_LNKCAP2_CROSSLINK	0x00000100 /* Crosslink supported */
>  #define PCI_EXP_LNKCTL2		48	/* Link Control 2 */
>  #define  PCI_EXP_LNKCTL2_TLS		0x000f
> @@ -678,6 +681,7 @@
>  #define  PCI_EXP_LNKCTL2_TLS_8_0GT	0x0003 /* Supported Speed 8GT/s */
>  #define  PCI_EXP_LNKCTL2_TLS_16_0GT	0x0004 /* Supported Speed 16GT/s */
>  #define  PCI_EXP_LNKCTL2_TLS_32_0GT	0x0005 /* Supported Speed 32GT/s */
> +#define  PCI_EXP_LNKCTL2_TLS_64_0GT	0x0006 /* Supported Speed 64GT/s */
>  #define  PCI_EXP_LNKCTL2_ENTER_COMP	0x0010 /* Enter Compliance */
>  #define  PCI_EXP_LNKCTL2_TX_MARGIN	0x0380 /* Transmit Margin */
>  #define  PCI_EXP_LNKCTL2_HASD		0x0020 /* HW Autonomous Speed Disable */
> -- 
> 2.7.4
>