clk: sifive: Move all stuff into SoCs header files from C files

Improve PRCI driver to reduce the complexity, we remove the SoCs C files
by putting all stuff in each SoCs header files, and include these
SoCs-specific header files in core of PRCI. It can also avoid the W=1
kernel build warnings about variable defined but not used
[-Wunused-const-variable=], like commit 487dc7bb6a0c ("clk: sifive:
fu540-prci: Declare static const variable 'prci_clk_fu540' where it's
used") does.

Signed-off-by: Zong Li <zong.li@sifive.com>
Suggested-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/a3c7ec5c46c1d8be455d1c347db4855bb56cec53.1646388139.git.zong.li@sifive.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sifive: Add a driver for the SiFive FU740 PRCI IP block

Add driver code for the SiFive FU740 PRCI IP block. This IP block
handles reset and clock control for the SiFive FU740 device and
implements SoC-level clock tree controls and dividers.

The link of unmatched as follow, and the U740-C000 manual would
be present in the same page as soon.
https://www.sifive.com/boards/hifive-unmatched

This driver contains bug fixes and contributions from
Henry Styles <hes@sifive.com>
Erik Danie <erik.danie@sifive.com>
Pragnesh Patel <pragnesh.patel@sifive.com>

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Pragnesh Patel <Pragnesh.patel@sifive.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Henry Styles <hes@sifive.com>
Cc: Erik Danie <erik.danie@sifive.com>
Cc: Pragnesh Patel <pragnesh.patel@sifive.com>
Link: https://lore.kernel.org/r/20201209094916.17383-4-zong.li@sifive.com
[sboyd@kernel.org: Include header to silence sparse]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sifive: Use common name for prci configuration

Use generic name CLK_SIFIVE_PRCI instead of CLK_SIFIVE_FU540_PRCI. This
patch is prepared for fu740 support.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Reviewed-by: Pragnesh Patel <Pragnesh.patel@sifive.com>
Link: https://lore.kernel.org/r/20201209094916.17383-3-zong.li@sifive.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sifive: Extract prci core to common base

Extract common core of prci driver to an independent file, it could
allow other chips to reuse it. Separate SoCs-dependent code 'fu540'
from prci core, then we can easily add 'fu740' later.

Almost these changes are code movement. The different is adding the
private data for each SoC use, so it needs to get match data in probe
callback function, then use the data for initialization.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Pragnesh Patel <Pragnesh.patel@sifive.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Link: https://lore.kernel.org/r/20201209094916.17383-2-zong.li@sifive.com
[sboyd@kernel.org: Include header to silence sparse]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clk: sifive: add a driver for the SiFive FU540 PRCI IP block

Add driver code for the SiFive FU540 PRCI IP block. This IP block
handles reset and clock control for the SiFive FU540 device and
implements SoC-level clock tree controls and dividers.

Based on code written by Wesley Terpstra <wesley@sifive.com>:
https://github.com/riscv/riscv-linux/commit/999529edf517ed75b56659d456d221b2ee56bb60

Boot and PLL rate change were tested on a SiFive HiFive Unleashed
board.

This version includes several changes requested by Stephen Boyd
<sboyd@kernel.org>.

Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Wesley W. Terpstra <wesley@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Megan Wachs <megan@sifive.com>
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-clk@vger.kernel.org
[sboyd@kernel.org: Fix some const and ARRAY_SIZE() issues, make makefile
only descend if CLK_SIFIVE=y]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>