acpi: Support generation of SPI descriptor
Add a function to write a SPI descriptor to the generated ACPI code.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/lib/acpi/acpi_device.c b/lib/acpi/acpi_device.c
index c0d5a9a..b628fa1 100644
--- a/lib/acpi/acpi_device.c
+++ b/lib/acpi/acpi_device.c
@@ -492,3 +492,127 @@
return ret;
}
+
+#ifdef CONFIG_SPI
+/* ACPI 6.1 section 6.4.3.8.2.2 - SpiSerialBus() */
+static void acpi_device_write_spi(struct acpi_ctx *ctx, const struct acpi_spi *spi)
+{
+ void *desc_length, *type_length;
+ u16 flags = 0;
+
+ /* Byte 0: Descriptor Type */
+ acpigen_emit_byte(ctx, ACPI_DESCRIPTOR_SERIAL_BUS);
+
+ /* Byte 1+2: Length (filled in later) */
+ desc_length = largeres_write_len_f(ctx);
+
+ /* Byte 3: Revision ID */
+ acpigen_emit_byte(ctx, ACPI_SPI_SERIAL_BUS_REVISION_ID);
+
+ /* Byte 4: Resource Source Index is Reserved */
+ acpigen_emit_byte(ctx, 0);
+
+ /* Byte 5: Serial Bus Type is SPI */
+ acpigen_emit_byte(ctx, ACPI_SERIAL_BUS_TYPE_SPI);
+
+ /*
+ * Byte 6: Flags
+ * [7:2]: 0 => Reserved
+ * [1]: 1 => ResourceConsumer
+ * [0]: 0 => ControllerInitiated
+ */
+ acpigen_emit_byte(ctx, BIT(1));
+
+ /*
+ * Byte 7-8: Type Specific Flags
+ * [15:2]: 0 => Reserveda
+ * [1]: 0 => ActiveLow, 1 => ActiveHigh
+ * [0]: 0 => FourWire, 1 => ThreeWire
+ */
+ if (spi->wire_mode == SPI_3_WIRE_MODE)
+ flags |= BIT(0);
+ if (spi->device_select_polarity == SPI_POLARITY_HIGH)
+ flags |= BIT(1);
+ acpigen_emit_word(ctx, flags);
+
+ /* Byte 9: Type Specific Revision ID */
+ acpigen_emit_byte(ctx, ACPI_SPI_TYPE_SPECIFIC_REVISION_ID);
+
+ /* Byte 10-11: SPI Type Data Length */
+ type_length = largeres_write_len_f(ctx);
+
+ /* Byte 12-15: Connection Speed */
+ acpigen_emit_dword(ctx, spi->speed);
+
+ /* Byte 16: Data Bit Length */
+ acpigen_emit_byte(ctx, spi->data_bit_length);
+
+ /* Byte 17: Clock Phase */
+ acpigen_emit_byte(ctx, spi->clock_phase);
+
+ /* Byte 18: Clock Polarity */
+ acpigen_emit_byte(ctx, spi->clock_polarity);
+
+ /* Byte 19-20: Device Selection */
+ acpigen_emit_word(ctx, spi->device_select);
+
+ /* Fill in Type Data Length */
+ largeres_fill_len(ctx, type_length);
+
+ /* Byte 21+: ResourceSource String */
+ acpigen_emit_string(ctx, spi->resource);
+
+ /* Fill in SPI Descriptor Length */
+ largeres_fill_len(ctx, desc_length);
+}
+
+/**
+ * acpi_device_set_spi() - Set up an ACPI SPI struct from a device
+ *
+ * The value of @scope is not copied, but only referenced. This implies the
+ * caller has to ensure it stays valid for the lifetime of @spi.
+ *
+ * @dev: SPI device to convert
+ * @spi: Place to put the new structure
+ * @scope: Scope of the SPI device (this is the controller path)
+ * @return 0 (always)
+ */
+static int acpi_device_set_spi(const struct udevice *dev, struct acpi_spi *spi,
+ const char *scope)
+{
+ struct dm_spi_slave_platdata *plat;
+ struct spi_slave *slave = dev_get_parent_priv(dev);
+
+ plat = dev_get_parent_platdata(slave->dev);
+ memset(spi, '\0', sizeof(*spi));
+ spi->device_select = plat->cs;
+ spi->device_select_polarity = SPI_POLARITY_LOW;
+ spi->wire_mode = SPI_4_WIRE_MODE;
+ spi->speed = plat->max_hz;
+ spi->data_bit_length = slave->wordlen;
+ spi->clock_phase = plat->mode & SPI_CPHA ?
+ SPI_CLOCK_PHASE_SECOND : SPI_CLOCK_PHASE_FIRST;
+ spi->clock_polarity = plat->mode & SPI_CPOL ?
+ SPI_POLARITY_HIGH : SPI_POLARITY_LOW;
+ spi->resource = scope;
+
+ return 0;
+}
+
+int acpi_device_write_spi_dev(struct acpi_ctx *ctx, const struct udevice *dev)
+{
+ char scope[ACPI_PATH_MAX];
+ struct acpi_spi spi;
+ int ret;
+
+ ret = acpi_device_scope(dev, scope, sizeof(scope));
+ if (ret)
+ return log_msg_ret("scope", ret);
+ ret = acpi_device_set_spi(dev, &spi, scope);
+ if (ret)
+ return log_msg_ret("set", ret);
+ acpi_device_write_spi(ctx, &spi);
+
+ return 0;
+}
+#endif /* CONFIG_SPI */