uart: Add support for snps,dw-apb-uart clock and hwreset resources

[jmcneill]

Summary

This change moves support for Synopsys Designware APB UART out of ns8250 into a separate driver, and adds support for activating clock and hwreset resources when the EXT_RESOURCES option is present.

[manu_bidouilliste.com]

sys/arm/conf/A20

75

Shouldn't the dependancy on ns8250 be handled in sys/conf/files ?
Something like :
dev/uart/uart_dev_ns8250.c optional uart uart_ns8250 | uart_snps

I'm really not sure if this kind of stuff is ok.

[andrew]

sys/arm/conf/A20

75

When you have two options that need to be set it would be: ... optional uart uart_foo | uart uart_bar

[jmcneill]

• Make uart_snps depend on uart_ns8250
• Remove redundant clk_disable calls before clk_release

[manu_bidouilliste.com]

sys/dev/uart/uart_dev_ns8250.c

460

This doesn't seems to be needed anymore, the busy-detect property was when ns8250 wasn't snps aware.

[andrew]

sys/dev/uart/uart_dev_ns8250.c

460

It was kept around to give people a chance to update their dtb. It can be removed now.

sys/dev/uart/uart_dev_snps.c

158

There seems to be a lot happening in this probe function that should be moved to attach.

[jmcneill]

sys/dev/uart/uart_dev_snps.c

158

Two problems --

• uart_bus_probe needs to know the ref clock frequency
• uart_bus_probe -> ns8250_bus_probe access registers, so clocks must be enabled

[jmcneill]

• uart_dev_ns8250: Remove support for "busy-detect" property.
• uart_dev_snps: allow to attach to ofwbus as well as simplebus to match uart_bus_fdt behavior.

[mmel]

sys/dev/uart/uart_dev_snps.c

285

This is not needed. Owfbus is subclass of simplebus for some time, so binding to simplebus also matches to ofwbus.

[andrew]

sys/dev/uart/uart_dev_snps.c

285

Have you tested this? I've found both are needed if the device could be a child of either.

[mmel]

sys/dev/uart/uart_dev_snps.c

285

Yes, sure. Tegra, for example, doesn't not have 'base' SoC simplebus at all, all devices are children of ofwbus. Binding to base class also matches to all its subclasses.

[jmcneill]

Remove binding to ofwbus