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The ARM Server Base System Architecture[1] document describes a generic UART which is a subset of the PL011 UART. It lacks DMA support, baud rate control and modem status line control, among other things. The idea is to move the UART initialization and setup into the firmware (which does this job today already) and let the kernel just use the UART for sending and receiving characters. We use the recent refactoring to build a new struct uart_ops variable which points to some new functions avoiding access to the missing registers. We reuse as much existing PL011 code as possible. In contrast to the PL011 the SBSA UART does not define any AMBA or PrimeCell relations, so we go with a pretty generic probe function which only uses platform device functions. A DT binding is provided with this patch, ACPI support is added in a separate one. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Tested-by: Mark Langsdorf <mlangsdo@redhat.com> Tested-by: Naresh Bhat <nbhat@cavium.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
11 lines
438 B
Plaintext
11 lines
438 B
Plaintext
* ARM SBSA defined generic UART
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This UART uses a subset of the PL011 registers and consequently lives
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in the PL011 driver. It's baudrate and other communication parameters
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cannot be adjusted at runtime, so it lacks a clock specifier here.
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Required properties:
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- compatible: must be "arm,sbsa-uart"
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- reg: exactly one register range
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- interrupts: exactly one interrupt specifier
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- current-speed: the (fixed) baud rate set by the firmware
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