027fa4dee9
- There are three PHY lanes on iMX8QM, and can be
used in the following three cases
1. a two lanes PCIE_A, and a single lane SATA.
2. a single lane PCIE_A, a single lane PCIE_B
and a single lane SATA.
3. a two lanes PCIE_A, and a single lane PCIE_B.
The configuration of the iMX8QM AHCI SATA is relied
on the usage of PCIE ports in the case 1 and 2.
Use standalone iMX8 AHCI SATA probe and enable
functions to enable iMX8QM AHCI SATA support.
- To save power consumption, PHY CLKs can be gated
off after the configurations are done.
- The impedance ratio should be configured refer to
differnet REXT values.
0x6c <--> REXT value is 85Ohms
0x80 (default value) <--> REXT value is 100Ohms.
In general, REXT value should be 85ohms in standalone
PCIE HW board design, and 100ohms in SATA standalone
HW board design.
When the PCIE and the SATA are enabled simultaneously
in the HW board design. The REXT value would be set
to 85ohms.
Configure the SATA PHY impedance ratio to 0x6c in
default.
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.