clk: ingenic: jz4760: Update M/N/OD calculation algorithm

The previous algorithm was pretty broken.

- The inner loop had a '(m > m_max)' condition, and the value of 'm'
would increase in each iteration;

- Each iteration would actually multiply 'm' by two, so it is not needed
to re-compute the whole equation at each iteration;

- It would loop until (m & 1) == 0, which means it would loop at most
once.

- The outer loop would divide the 'n' value by two at the end of each
iteration. This meant that for a 12 MHz parent clock and a 1.2 GHz
requested clock, it would first try n=12, then n=6, then n=3, then
n=1, none of which would work; the only valid value is n=2 in this
case.

Simplify this algorithm with a single for loop, which decrements 'n'
after each iteration, addressing all of the above problems.

Fixes: bdbfc029374f ("clk: ingenic: Add support for the JZ4760")
Cc: <stable@vger.kernel.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20221214123704.7305-1-paul@crapouillou.net
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: ingenic: Mark critical clocks in Ingenic SoCs

Consider CPU, L2 cache, and memory clocks as critical to prevent
them -- and the parent clocks -- from being automatically gated,
since nothing calls clk_get() on these clocks.

Gating the CPU clock hangs the processor, and gating memory makes
external DRAM inaccessible. Normal kernel code can't hope to deal
with either situation so those clocks have to be critical.

The L2 cache is required only if caches are running, and could be
gated if the kernel takes care to flush and disable caches before
gating the clock. There's no mechanism to do this, and probably no
reason to do it, so it's simpler to mark the L2 cache as critical.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220428164454.17908-3-aidanmacdonald.0x0@gmail.com
Tested-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com> # On X1000 and X1830
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: ingenic: Add MDMA and BDMA clocks

The Ingenic JZ4760 and JZ4770 both have an extra DMA core named BDMA
dedicated to the NAND and BCH controller, but which can also do
memory-to-memory transfers. The JZ4760 additionally has a DMA core named
MDMA dedicated to memory-to-memory transfers. The programming manual for
the JZ4770 does have a bit for a MDMA clock, but does not seem to have
the hardware wired in.

Add the BDMA and MDMA clocks to the JZ4760 CGU code, and the BDMA clock
to the JZ4770 code, so that the BDMA and MDMA controllers can be used.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20211220193319.114974-3-paul@crapouillou.net
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

dt-bindings: Rename Ingenic CGU headers to ingenic,*.h

Tidy up a bit the tree, by prefixing all include/dt-bindings/clock/ files
related to Ingenic SoCs with 'ingenic,'.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211016133322.40771-1-paul@crapouillou.net

clk: ingenic: Add support for the JZ4760

Add the CGU code and the compatible string to the TCU driver to support
the JZ4760 SoC.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20210530164923.18134-7-paul@crapouillou.net
Signed-off-by: Stephen Boyd <sboyd@kernel.org>