mb/lowrisc/nexys4ddr: Actually fix the UART clock setup
Ron's code calculated the DLL and DLM registers of the 8250 UART, but that's the job of the UART driver. uart_input_clock_divider isn't needed anymore because the default value of 16 works. As a bonus, the baud rate can now be selected in Kconfig, instead of being hardcoded at 115200. TEST=Booted the board at 9600 and 115200 baud. Change-Id: I3d5e49568b798a6a6d944db1161def7d0a2d3b48 Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Reviewed-on: https://review.coreboot.org/17188 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Martin Roth <martinroth@google.com> Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
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@ -21,7 +21,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
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select DRIVERS_UART_8250MEM
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select BOOT_DEVICE_NOT_SPI_FLASH
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select UART_OVERRIDE_REFCLK
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select UART_OVERRIDE_INPUT_CLOCK_DIVIDER
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config MAINBOARD_DIR
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string
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@ -24,17 +24,8 @@ uintptr_t uart_platform_base(int idx)
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return (uintptr_t) 0x42000000;
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}
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/* these are currently not quite right but they are here for reference
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* and will be fixed when lowrisc gives us a standard clock
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* and set of values. */
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// divisor = clk_freq / (16 * Baud)
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unsigned int uart_input_clock_divider(void)
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{
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return (25 * 1000 * 1000u / (16u * 115200u)) % 0x100;
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}
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// System clock 25 MHz, 115200 baud rate
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/* The clock which the UART is based on */
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unsigned int uart_platform_refclk(void)
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{
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return (25 * 1000 * 1000u / (16u * 115200u)) >> 8;
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return 25 * MHz;
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}
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