d3f623ae8e
Introduce function _scsih_nvme_shutdown() to issue IO Unit Control message to IOC firmware with operation code 'shutdown'. This causes IOC firmware to issue NVMe shutdown commands to all NVMe drives attached to it. NVMe Shutdown: NVMe devices need to have a specific shutdown sequence performed before power is removed. For this, the IOC firmware needs to be notified when the system is being shutdown. So during the system shutdown time, driver issues an IO Unit Control request with operation code MPI26_CTRL_OP_SHUTDOWN to inform firmware that a shutdown is initiated. This shutdown command is issued only if NVMe devices are attached to the controller. During each NVMe device addition, driver reads pcie device page2 to get shutdown latency (e.g. drive's RTD3 Entry Latency) and updates the max latency value among the added NVMe drives in ioc->max_shutdown_latency. This is used as the timeout value for IO Unit Control command at the time of shutdown. When a NVMe drive is removed and its shutdown latency matches which ioc->max_shutdown_latency then ioc->max_shutdown_latency is updated to next max value (by iterating over the list of available devices). If the shutdown latency is 0, then default timeout is set to six seconds. Link: https://lore.kernel.org/r/20191226111333.26131-3-sreekanth.reddy@broadcom.com Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.