microwatt

Commit Graph

Author	SHA1	Message	Date
Benjamin Herrenschmidt	3b603402d2	soc_reset: Use counters, add synchronizers In some cases we need to keep the reset held for much longer, so use counters rather than shift registers. Additionally, some signals such as ext_rst and pll_locked or signals going from the ext_clk domain to the pll_clk domain need to be treated as async, and testing them without synchronizers is asking for trouble. Finally, make the external reset also reset the PLL. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>	5 years ago
Anton Blanchard	03fd06deaf	Rework SOC reset The old reset code was overly complicated and never worked properly. Replace it with a simpler sequence that uses a couple of shift registers to assert resets: - Wait a number of external clock cycles before removing reset from the PLL. - After the PLL locks and the external reset button isn't pressed, wait a number of PLL clock cycles before removing reset from the SOC. Signed-off-by: Anton Blanchard <anton@linux.ibm.com>	6 years ago

Author

SHA1

Message

Date

Benjamin Herrenschmidt

3b603402d2

soc_reset: Use counters, add synchronizers

In some cases we need to keep the reset held for much longer,
so use counters rather than shift registers.

Additionally, some signals such as ext_rst and pll_locked
or signals going from the ext_clk domain to the pll_clk
domain need to be treated as async, and testing them without
synchronizers is asking for trouble.

Finally, make the external reset also reset the PLL.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Anton Blanchard

03fd06deaf

Rework SOC reset

The old reset code was overly complicated and never worked properly.
Replace it with a simpler sequence that uses a couple of shift registers
to assert resets:

- Wait a number of external clock cycles before removing reset from
  the PLL.

- After the PLL locks and the external reset button isn't pressed,
  wait a number of PLL clock cycles before removing reset from the SOC.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>

2 Commits (cc4dcb3597914bcf6730cdbabc7fbe3605c80c94)