Théo Lebrun 563f8598cb spi: cadence-qspi: minimise register accesses on each op if !DTR
cqspi_enable_dtr() is called for each operation, commands or not, reads
or writes. It writes CQSPI_REG_CONFIG then waits for idle (three
successful reads). Skip that in the no-DTR case if DTR is already
disabled.

It cannot be skipped in the DTR case as cqspi_setup_opcode_ext() writes
to a register and we must wait for idle state.

According to ftrace, the average cqspi_exec_mem_op() call goes from
85.4µs to 83.6µs when reading 235M over UBIFS on an octal flash.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://msgid.link/r/20240405-cdns-qspi-mbly-v2-6-956679866d6d@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2024-04-08 15:18:10 +01:00
2022-09-28 09:02:20 +02:00
2024-03-24 14:10:05 -07:00
2024-03-18 03:36:32 -06:00

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 reStructuredText 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.
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