[PATCH v2 11/35] acpi: Support generation of I2C descriptor
Simon Glass
sjg at chromium.org
Sun May 10 22:33:45 CEST 2020
Add a function to write a GPIO descriptor to the generated ACPI code.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2:
- Fix memset of I2C descriptor
Changes in v1: None
drivers/i2c/sandbox_i2c.c | 11 ++++
drivers/rtc/sandbox_rtc.c | 13 +++++
include/acpi/acpi_device.h | 36 +++++++++++++
lib/acpi/acpi_device.c | 103 +++++++++++++++++++++++++++++++++++++
test/dm/acpigen.c | 32 ++++++++++++
5 files changed, 195 insertions(+)
diff --git a/drivers/i2c/sandbox_i2c.c b/drivers/i2c/sandbox_i2c.c
index f4ae2397a0..125026da90 100644
--- a/drivers/i2c/sandbox_i2c.c
+++ b/drivers/i2c/sandbox_i2c.c
@@ -11,6 +11,7 @@
#include <i2c.h>
#include <log.h>
#include <asm/test.h>
+#include <dm/acpi.h>
#include <dm/lists.h>
#include <dm/device-internal.h>
@@ -83,6 +84,15 @@ static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
return ops->xfer(emul, msg, nmsgs);
}
+static int sandbox_i2c_get_name(const struct udevice *dev, char *out_name)
+{
+ return acpi_copy_name(out_name, "SI2C");
+}
+
+struct acpi_ops sandbox_i2c_acpi_ops = {
+ .get_name = sandbox_i2c_get_name,
+};
+
static const struct dm_i2c_ops sandbox_i2c_ops = {
.xfer = sandbox_i2c_xfer,
};
@@ -98,4 +108,5 @@ U_BOOT_DRIVER(i2c_sandbox) = {
.of_match = sandbox_i2c_ids,
.ops = &sandbox_i2c_ops,
.priv_auto_alloc_size = sizeof(struct sandbox_i2c_priv),
+ ACPI_OPS_PTR(&sandbox_i2c_acpi_ops)
};
diff --git a/drivers/rtc/sandbox_rtc.c b/drivers/rtc/sandbox_rtc.c
index b08d758a74..f2906c3397 100644
--- a/drivers/rtc/sandbox_rtc.c
+++ b/drivers/rtc/sandbox_rtc.c
@@ -9,6 +9,7 @@
#include <i2c.h>
#include <rtc.h>
#include <asm/rtc.h>
+#include <dm/acpi.h>
#define REG_COUNT 0x80
@@ -84,6 +85,17 @@ static int sandbox_rtc_write8(struct udevice *dev, unsigned int reg, int val)
return dm_i2c_reg_write(dev, reg, val);
}
+#if CONFIG_IS_ENABLED(ACPIGEN)
+static int sandbox_rtc_get_name(const struct udevice *dev, char *out_name)
+{
+ return acpi_copy_name(out_name, "RTCC");
+}
+
+struct acpi_ops sandbox_rtc_acpi_ops = {
+ .get_name = sandbox_rtc_get_name,
+};
+#endif
+
static const struct rtc_ops sandbox_rtc_ops = {
.get = sandbox_rtc_get,
.set = sandbox_rtc_set,
@@ -102,4 +114,5 @@ U_BOOT_DRIVER(rtc_sandbox) = {
.id = UCLASS_RTC,
.of_match = sandbox_rtc_ids,
.ops = &sandbox_rtc_ops,
+ ACPI_OPS_PTR(&sandbox_rtc_acpi_ops)
};
diff --git a/include/acpi/acpi_device.h b/include/acpi/acpi_device.h
index 70c151d150..cf1ac695a7 100644
--- a/include/acpi/acpi_device.h
+++ b/include/acpi/acpi_device.h
@@ -9,6 +9,7 @@
#ifndef __ACPI_DEVICE_H
#define __ACPI_DEVICE_H
+#include <i2c.h>
#include <linux/bitops.h>
struct acpi_ctx;
@@ -183,6 +184,29 @@ struct acpi_gpio {
enum acpi_gpio_polarity polarity;
};
+/* ACPI Descriptors for Serial Bus interfaces */
+#define ACPI_SERIAL_BUS_TYPE_I2C 1
+#define ACPI_SERIAL_BUS_TYPE_SPI 2
+#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
+
+/**
+ * struct acpi_i2c - representation of an ACPI I2C device
+ *
+ * @address: 7-bit or 10-bit I2C address
+ * @mode_10bit: Which address size is used
+ * @speed: Bus speed in Hz
+ * @resource: Resource name for the I2C controller
+ */
+struct acpi_i2c {
+ u16 address;
+ enum i2c_address_mode mode_10bit;
+ enum i2c_speed_rate speed;
+ const char *resource;
+};
+
/**
* acpi_device_path() - Get the full path to an ACPI device
*
@@ -270,4 +294,16 @@ int acpi_device_write_gpio_desc(struct acpi_ctx *ctx,
int acpi_device_write_interrupt_or_gpio(struct acpi_ctx *ctx,
struct udevice *dev, const char *prop);
+/**
+ * acpi_device_write_i2c_dev() - Write an I2C device to ACPI
+ *
+ * This creates a I2cSerialBus descriptor for an I2C device, including
+ * information ACPI needs to use it.
+ *
+ * @ctx: ACPI context pointer
+ * @dev: I2C device to write
+ * @return 0 if OK, -ve on error
+ */
+int acpi_device_write_i2c_dev(struct acpi_ctx *ctx, const struct udevice *dev);
+
#endif
diff --git a/lib/acpi/acpi_device.c b/lib/acpi/acpi_device.c
index 423b91cfd2..0136a0bdc9 100644
--- a/lib/acpi/acpi_device.c
+++ b/lib/acpi/acpi_device.c
@@ -381,3 +381,106 @@ int acpi_device_write_interrupt_or_gpio(struct acpi_ctx *ctx,
return 0;
}
+
+/* ACPI 6.3 section 6.4.3.8.2.1 - I2cSerialBus() */
+static void acpi_device_write_i2c(struct acpi_ctx *ctx,
+ const struct acpi_i2c *i2c)
+{
+ void *desc_length, *type_length;
+
+ /* Byte 0: Descriptor Type */
+ acpigen_emit_byte(ctx, ACPI_DESCRIPTOR_SERIAL_BUS);
+
+ /* Byte 1+2: Length (filled in later) */
+ desc_length = acpi_device_write_zero_len(ctx);
+
+ /* Byte 3: Revision ID */
+ acpigen_emit_byte(ctx, ACPI_I2C_SERIAL_BUS_REVISION_ID);
+
+ /* Byte 4: Resource Source Index is Reserved */
+ acpigen_emit_byte(ctx, 0);
+
+ /* Byte 5: Serial Bus Type is I2C */
+ acpigen_emit_byte(ctx, ACPI_SERIAL_BUS_TYPE_I2C);
+
+ /*
+ * Byte 6: Flags
+ * [7:2]: 0 => Reserved
+ * [1]: 1 => ResourceConsumer
+ * [0]: 0 => ControllerInitiated
+ */
+ acpigen_emit_byte(ctx, 1 << 1);
+
+ /*
+ * Byte 7-8: Type Specific Flags
+ * [15:1]: 0 => Reserved
+ * [0]: 0 => 7bit, 1 => 10bit
+ */
+ acpigen_emit_word(ctx, i2c->mode_10bit);
+
+ /* Byte 9: Type Specific Revision ID */
+ acpigen_emit_byte(ctx, ACPI_I2C_TYPE_SPECIFIC_REVISION_ID);
+
+ /* Byte 10-11: I2C Type Data Length */
+ type_length = acpi_device_write_zero_len(ctx);
+
+ /* Byte 12-15: I2C Bus Speed */
+ acpigen_emit_dword(ctx, i2c->speed);
+
+ /* Byte 16-17: I2C Slave Address */
+ acpigen_emit_word(ctx, i2c->address);
+
+ /* Fill in Type Data Length */
+ acpi_device_fill_len(ctx, type_length);
+
+ /* Byte 18+: ResourceSource */
+ acpigen_emit_string(ctx, i2c->resource);
+
+ /* Fill in I2C Descriptor Length */
+ acpi_device_fill_len(ctx, desc_length);
+}
+
+/**
+ * acpi_device_set_i2c() - Set up an ACPI I2C struct from a device
+ *
+ * @dev: I2C device to convert
+ * @i2c: Place to put the new structure
+ * @scope: Scope of the I2C device (this is the controller path)
+ * @return 0 (always)
+ */
+static int acpi_device_set_i2c(const struct udevice *dev, struct acpi_i2c *i2c,
+ const char *scope)
+{
+ struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
+ struct udevice *bus = dev_get_parent(dev);
+
+ memset(i2c, '\0', sizeof(*i2c));
+ i2c->address = chip->chip_addr;
+ i2c->mode_10bit = 0;
+
+ /*
+ * i2c_bus->speed_hz is set if this device is probed, but if not we
+ * must use the device tree
+ */
+ i2c->speed = dev_read_u32_default(bus, "clock-frequency", 100000);
+ i2c->resource = scope;
+
+ return 0;
+}
+
+int acpi_device_write_i2c_dev(struct acpi_ctx *ctx, const struct udevice *dev)
+{
+ char scope[ACPI_PATH_MAX];
+ struct acpi_i2c i2c;
+ int ret;
+
+ ret = acpi_device_scope(dev, scope, sizeof(scope));
+ if (ret)
+ return log_msg_ret("scope", ret);
+ ret = acpi_device_set_i2c(dev, &i2c, scope);
+ if (ret)
+ return log_msg_ret("set", ret);
+ acpi_device_write_i2c(ctx, &i2c);
+
+ return 0;
+}
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index 6aefa6845d..de9996ab35 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -266,3 +266,35 @@ static int dm_test_acpi_interrupt_or_gpio(struct unit_test_state *uts)
}
DM_TEST(dm_test_acpi_interrupt_or_gpio,
DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test emitting an I2C descriptor */
+static int dm_test_acpi_i2c(struct unit_test_state *uts)
+{
+ struct acpi_ctx *ctx;
+ struct udevice *dev;
+ u8 *ptr;
+
+ ut_assertok(alloc_context(&ctx));
+
+ ptr = acpigen_get_current(ctx);
+
+ ut_assertok(uclass_get_device(UCLASS_RTC, 0, &dev));
+ ut_assertok(acpi_device_write_i2c_dev(ctx, dev));
+ ut_asserteq(28, acpigen_get_current(ctx) - ptr);
+ ut_asserteq(ACPI_DESCRIPTOR_SERIAL_BUS, ptr[0]);
+ ut_asserteq(25, get_unaligned((u16 *)(ptr + 1)));
+ ut_asserteq(ACPI_I2C_SERIAL_BUS_REVISION_ID, ptr[3]);
+ ut_asserteq(0, ptr[4]);
+ ut_asserteq(ACPI_SERIAL_BUS_TYPE_I2C, ptr[5]);
+ ut_asserteq(0, get_unaligned((u16 *)(ptr + 7)));
+ ut_asserteq(ACPI_I2C_TYPE_SPECIFIC_REVISION_ID, ptr[9]);
+ ut_asserteq(6, get_unaligned((u16 *)(ptr + 10)));
+ ut_asserteq(100000, get_unaligned((u32 *)(ptr + 12)));
+ ut_asserteq(0x43, get_unaligned((u16 *)(ptr + 16)));
+ ut_asserteq_str("\\_SB.SI2C", (char *)ptr + 18);
+
+ free_context(&ctx);
+
+ return 0;
+}
+DM_TEST(dm_test_acpi_i2c, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
--
2.26.2.645.ge9eca65c58-goog
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