Home
last modified time | relevance | path

Searched hist:"130 f1b8f" (Results 1 – 1 of 1) sorted by relevance

/openbmc/linux/include/uapi/linux/
H A Dpci_regs.h130f1b8f Wed Dec 26 11:39:23 CST 2012 Bjorn Helgaas <bhelgaas@google.com> PCI: Add PCIe Link Capability link speed and width names

Add standard #defines for the Supported Link Speeds field in the PCIe
Link Capabilities register.

Note that prior to PCIe spec r3.0, these encodings were defined:

0001b 2.5GT/s Link speed supported
0010b 5.0GT/s and 2.5GT/s Link speed supported

Starting with spec r3.0, these encodings refer to bits 0 and 1 in the
Supported Link Speeds Vector in the Link Capabilities 2 register, and bits
0 and 1 there mean 2.5 GT/s and 5.0 GT/s, respectively. Therefore, code
that followed r2.0 and interpreted 0x1 as 2.5GT/s and 0x2 as 5.0GT/s will
continue to work, and we can identify a device using the new encodings
because it will have a non-zero Link Capabilities 2 register.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
130f1b8f Wed Dec 26 11:39:23 CST 2012 Bjorn Helgaas <bhelgaas@google.com> PCI: Add PCIe Link Capability link speed and width names

Add standard #defines for the Supported Link Speeds field in the PCIe
Link Capabilities register.

Note that prior to PCIe spec r3.0, these encodings were defined:

0001b 2.5GT/s Link speed supported
0010b 5.0GT/s and 2.5GT/s Link speed supported

Starting with spec r3.0, these encodings refer to bits 0 and 1 in the
Supported Link Speeds Vector in the Link Capabilities 2 register, and bits
0 and 1 there mean 2.5 GT/s and 5.0 GT/s, respectively. Therefore, code
that followed r2.0 and interpreted 0x1 as 2.5GT/s and 0x2 as 5.0GT/s will
continue to work, and we can identify a device using the new encodings
because it will have a non-zero Link Capabilities 2 register.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>