Date: Tue, 3 Apr 2007 17:48:58 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: freebsd-arm@freebsd.org Cc: Bernd Walter <ticso@cicely12.cicely.de> Subject: adding 16550 UART to RM9200 Message-ID: <20070403154858.GR80382@cicely12.cicely.de>
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I plan to add up to 48 16550 UART to an RM9200 system. It should be done with 16C554 chips - so I only have 16 byte FiFo. I would like to avoid using 64 byte FiFo chips, but those are pin compatible, so things are changeable in case. Likely most of the ports are doing low volume and I hope this will be Ok. They will be addressed via NCS2 space. Most of the external interrupts are not available because of unfortunate multiplexing with other required signals, so I have to attach them all to IRQ0. The interrupt will be level configured by firmware. And the NCS2 waitstates and buswidth will be configured by firmware as well. However some question points are still left: - How can I attach our uart(4) driver to the chips? It will likely addressed with: UART0 0x30000000 - 0x30000007 IRQ0 UART1 0x30000008 - 0x3000000f IRQ0 UART2 0x30000010 - 0x30000017 IRQ0 UART3 0x30000018 - 0x3000001f IRQ0 UART4 0x30000020 - 0x30000027 IRQ0 UART5 0x30000028 - 0x3000002f IRQ0 [...] UART47 0x30000170 - 0x30000177 IRQ0 UART48 0x30000178 - 0x3000017f IRQ0 - I would like to use a 14,7456MHz xtal How can I tell uart(4) the frequency? - How can I configure NCS2 range as being uncacheable? I asume this has to be done somehow in the kernel. -- B.Walter http://www.bwct.de http://www.fizon.de bernd@bwct.de info@bwct.de support@fizon.de
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