acpi: Add support for writing UART device descriptors
This change adds support for generating the device descriptor that
corresponds to the UARTSerialBusV2() ACPI macro.
The resulting ACPI code for ACPI_UART_RAW_DEVICE(115200, 64) is:
UartSerialBusV2 (0x0001C200, DataBitsEight, StopBitsOne,
0x00, LittleEndian, ParityTypeNone, FlowControlNone,
0x0040, 0x0040, "\\_SB.PCI0.UAR2",
0x00, ResourceConsumer, , Exclusive)
Change-Id: I671ce2a499d74717d8677528c46ab3fbc1d7faf5
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41792
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
diff --git a/src/acpi/device.c b/src/acpi/device.c
index 9e8efa4..9ce86eb 100644
--- a/src/acpi/device.c
+++ b/src/acpi/device.c
@@ -523,6 +523,80 @@
acpi_device_fill_len(desc_length);
}
+/* UART Serial Bus - UARTSerialBusV2() */
+void acpi_device_write_uart(const struct acpi_uart *uart)
+{
+ void *desc_length, *type_length;
+ uint16_t flags;
+
+ /* Byte 0: Descriptor Type */
+ acpigen_emit_byte(ACPI_DESCRIPTOR_SERIAL_BUS);
+
+ /* Byte 1+2: Length (filled in later) */
+ desc_length = acpi_device_write_zero_len();
+
+ /* Byte 3: Revision ID */
+ acpigen_emit_byte(ACPI_UART_SERIAL_BUS_REVISION_ID);
+
+ /* Byte 4: Resource Source Index is Reserved */
+ acpigen_emit_byte(0);
+
+ /* Byte 5: Serial Bus Type is UART */
+ acpigen_emit_byte(ACPI_SERIAL_BUS_TYPE_UART);
+
+ /*
+ * Byte 6: Flags
+ * [7:2]: 0 => Reserved
+ * [1]: 1 => ResourceConsumer
+ * [0]: 0 => ControllerInitiated
+ */
+ acpigen_emit_byte(BIT(1));
+
+ /*
+ * Byte 7-8: Type Specific Flags
+ * [15:8]: 0 => Reserved
+ * [7]: 0 => Little Endian, 1 => Big Endian
+ * [6:4]: Data bits
+ * [3:2]: Stop bits
+ * [1:0]: Flow control
+ */
+ flags = uart->flow_control & 3;
+ flags |= (uart->stop_bits & 3) << 2;
+ flags |= (uart->data_bits & 7) << 4;
+ flags |= (uart->endian & 1) << 7;
+ acpigen_emit_word(flags);
+
+ /* Byte 9: Type Specific Revision ID */
+ acpigen_emit_byte(ACPI_UART_TYPE_SPECIFIC_REVISION_ID);
+
+ /* Byte 10-11: Type Data Length */
+ type_length = acpi_device_write_zero_len();
+
+ /* Byte 12-15: Initial Baud Rate */
+ acpigen_emit_dword(uart->initial_baud_rate);
+
+ /* Byte 16-17: RX FIFO size */
+ acpigen_emit_word(uart->rx_fifo_bytes);
+
+ /* Byte 18-19: TX FIFO size */
+ acpigen_emit_word(uart->tx_fifo_bytes);
+
+ /* Byte 20: Parity */
+ acpigen_emit_byte(uart->parity);
+
+ /* Byte 21: Lines Enabled */
+ acpigen_emit_byte(uart->lines_in_use);
+
+ /* Fill in Type Data Length */
+ acpi_device_fill_len(type_length);
+
+ /* Byte 22+: ResourceSource */
+ acpigen_emit_string(uart->resource);
+
+ /* Fill in Descriptor Length */
+ acpi_device_fill_len(desc_length);
+}
+
/* PowerResource() with Enable and/or Reset control */
void acpi_device_add_power_res(const struct acpi_power_res_params *params)
{
diff --git a/src/include/acpi/acpi_device.h b/src/include/acpi/acpi_device.h
index 2c2c67a..8cf36e3 100644
--- a/src/include/acpi/acpi_device.h
+++ b/src/include/acpi/acpi_device.h
@@ -323,10 +323,14 @@
#define ACPI_SERIAL_BUS_TYPE_I2C 1
#define ACPI_SERIAL_BUS_TYPE_SPI 2
+#define ACPI_SERIAL_BUS_TYPE_UART 3
+
#define ACPI_I2C_SERIAL_BUS_REVISION_ID 1 /* TODO: upgrade to 2 */
#define ACPI_I2C_TYPE_SPECIFIC_REVISION_ID 1
#define ACPI_SPI_SERIAL_BUS_REVISION_ID 1
#define ACPI_SPI_TYPE_SPECIFIC_REVISION_ID 1
+#define ACPI_UART_SERIAL_BUS_REVISION_ID 1
+#define ACPI_UART_TYPE_SPECIFIC_REVISION_ID 1
/*
* ACPI I2C Bus
@@ -372,6 +376,91 @@
/* Write SPI Bus descriptor to SSDT AML output */
void acpi_device_write_spi(const struct acpi_spi *spi);
+/*
+ * ACPI UART Bus
+ */
+
+enum acpi_uart_data_bits {
+ ACPI_UART_DATA_BITS_5,
+ ACPI_UART_DATA_BITS_6,
+ ACPI_UART_DATA_BITS_7,
+ ACPI_UART_DATA_BITS_8,
+ ACPI_UART_DATA_BITS_9
+};
+
+enum acpi_uart_stop_bits {
+ ACPI_UART_STOP_BITS_0,
+ ACPI_UART_STOP_BITS_1,
+ ACPI_UART_STOP_BITS_1_5,
+ ACPI_UART_STOP_BITS_2
+};
+
+enum acpi_uart_lines {
+ ACPI_UART_LINE_DTD = BIT(2), /* Data Carrier Detect */
+ ACPI_UART_LINE_RI = BIT(3), /* Ring Indicator */
+ ACPI_UART_LINE_DSR = BIT(4), /* Data Set Ready */
+ ACPI_UART_LINE_DTR = BIT(5), /* Data Terminal Ready */
+ ACPI_UART_LINE_CTS = BIT(6), /* Clear to Send */
+ ACPI_UART_LINE_RTS = BIT(7) /* Request to Send */
+};
+
+enum acpi_uart_endian {
+ ACPI_UART_ENDIAN_LITTLE,
+ ACPI_UART_ENDIAN_BIG
+};
+
+enum acpi_uart_parity {
+ ACPI_UART_PARITY_NONE,
+ ACPI_UART_PARITY_EVEN,
+ ACPI_UART_PARITY_ODD,
+ ACPI_UART_PARITY_MARK,
+ ACPI_UART_PARITY_SPACE
+};
+
+enum acpi_uart_flow_control {
+ ACPI_UART_FLOW_NONE,
+ ACPI_UART_FLOW_HARDWARE,
+ ACPI_UART_FLOW_SOFTWARE
+};
+
+struct acpi_uart {
+ /* Initial Baud Rate in bits per second */
+ uint32_t initial_baud_rate;
+ /* Number of bits of data in a packet (value between 5-9) */
+ enum acpi_uart_data_bits data_bits;
+ /* Number of bits to signal end of packet */
+ enum acpi_uart_stop_bits stop_bits;
+ /* Bitmask indicating presence or absence of particular line */
+ unsigned int lines_in_use;
+ /* Specify if the device expects big or little endian format */
+ enum acpi_uart_endian endian;
+ /* Specify the type of parity bits included after the data in a packet */
+ enum acpi_uart_parity parity;
+ /* Specify the flow control method */
+ enum acpi_uart_flow_control flow_control;
+ /* Upper limit in bytes of the buffer sizes for this device */
+ uint16_t rx_fifo_bytes;
+ uint16_t tx_fifo_bytes;
+ /* Set true if UART is shared, false if it is exclusive for one device */
+ bool shared;
+ /* Reference to UART controller */
+ const char *resource;
+};
+
+#define ACPI_UART_RAW_DEVICE(baud_rate, fifo_bytes) { \
+ .initial_baud_rate = (baud_rate), \
+ .data_bits = ACPI_UART_DATA_BITS_8, \
+ .stop_bits = ACPI_UART_STOP_BITS_1, \
+ .endian = ACPI_UART_ENDIAN_LITTLE, \
+ .parity = ACPI_UART_PARITY_NONE, \
+ .flow_control = ACPI_UART_FLOW_NONE, \
+ .rx_fifo_bytes = (fifo_bytes), \
+ .tx_fifo_bytes = (fifo_bytes), \
+ .shared = false }
+
+/* Write UARTSerialBusV2() descriptor to SSDT AML output */
+void acpi_device_write_uart(const struct acpi_uart *uart);
+
/* GPIO/timing information for the power on/off sequences */
struct acpi_power_res_params {
/* GPIO used to take device out of reset or to put it into reset. */