Allwinner A31 add smp support

[manu_bidouilliste.com]

Summary

Add SMP support to A31.
All allwinner SoC with the same number of core use the same register address for core configuration so we use that.
Move the file from a20/a20_mp.c to aw_mp.c

Test Plan

Apply patch and build kernel

[manu_bidouilliste.com]

Fix a bug, the power off gating reg is in the prcm region in the a31.

[andrew]

sys/arm/allwinner/aw_mp.c

73–74

Indentation (and below)

108–120

This is bogus, we should be checking which SoC we are on & mapping based on that.

[manu_bidouilliste.com]

Split start_ap in two function, one of each supported SoC.
Fix style(9).

[jmcneill_invisible.ca]

sys/arm/allwinner/aw_mp.c

168

Missing unmap for prcm handle

237

Missing unmap for prcm handle

[andrew]

sys/arm/allwinner/aw_mp.c

91

You can use cp15_l2ctlr_get here, from machine/cpu-v6.h.

92

Use CPUV7_L2CTLR_NPROC from machine/armreg.h

172

How similar are the two functions? i.e. could the common bits be pulled out to a helper function?

180

Split lines should be indented the same number of tabs, followed by 4 spaces.

213

8?

[manu_bidouilliste.com]

sys/arm/allwinner/aw_mp.c

213

We need to write 0xff, 0x7f, 0x3f etc ...
I guess I could add a CPU_POWER_CLAMP_STEPS define.

[manu_bidouilliste.com]

Merge back into one function and split the diff bits into switch statement.
Use cp15_l2ctlr_get and CPUV7_L2CTLR_NPROC instead of inline assembly.

[andrew]

sys/arm/allwinner/aw_mp.c

104–105

I think this code could be reworked a little to add separate functions for the two groups of SoCs. These would just map/unmap the registers, then call into common functions to power on the new CPUs. They should pass in the needed tag and handles, and maybe registers if applicable.

This would help for when we move to start CPUs through the PLATFORM code.

108

The indentation here was correct

136–137

This should be tabbed out to the same level as the previous line, followed by 4 spaces. You should then be able to fit both on a single line.

[manu_bidouilliste.com]

I'll wait till D5466 is commited to update this review.

[manu_bidouilliste.com]

Update diff to use PLATFORM_SMP bits.

[andrew]

sys/arm/allwinner/aw_mp.c

135–136

It looks like you don't need to split this line, it should be should enough.

137–138

These should be on a single line

162

Do we know the meaning of 3?

[manu_bidouilliste.com]

Add defines for previously hardcoded value.
Fix minor style(9) issues.

[manu_bidouilliste.com]

sys/arm/allwinner/aw_mp.c

162

Yeah, last diff add defines for this value.

[jmcneill]

sys/arm/allwinner/aw_mp.c

137

} else { on a single line

151

} else { on a single line

181

4 spaces instead of a tab for multi-line if

196

4 spaces instead of a tab for multi-line if

199

4 spaces instead of a tab for multi-line if

[manu_bidouilliste.com]

Fix style(9).

[andrew]

sys/arm/conf/A20

34

options <tab>

[manu_bidouilliste.com]

Fix space/tab in kernel config files.