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/*
* This file is part of the coreboot project.
*
* Copyright 2016 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <string.h>
#include <arch/acpi.h>
#include <arch/acpi_device.h>
#include <arch/acpigen.h>
#include <device/device.h>
#include <device/path.h>
/* Write empty word value and return pointer to it */
static void *acpi_device_write_zero_len(void)
{
char *p = acpigen_get_current();
acpigen_emit_word(0);
return p;
}
/* Fill in length value from start to current at specified location */
static void acpi_device_fill_from_len(char *ptr, char *start)
{
uint16_t len = acpigen_get_current() - start;
ptr[0] = len & 0xff;
ptr[1] = (len >> 8) & 0xff;
}
/*
* Fill in the length field with the value calculated from after
* the 16bit field to acpigen current as this length value does
* not include the length field itself.
*/
static void acpi_device_fill_len(void *ptr)
{
acpi_device_fill_from_len(ptr, ptr + sizeof(uint16_t));
}
/* Locate and return the ACPI name for this device */
const char *acpi_device_name(struct device *dev)
{
if (!dev)
return NULL;
/* Check for device specific handler */
if (dev->ops->acpi_name)
return dev->ops->acpi_name(dev);
/* Check parent device in case it has a global handler */
if (dev->bus && dev->bus->dev->ops->acpi_name)
return dev->bus->dev->ops->acpi_name(dev);
return NULL;
}
/* Recursive function to find the root device and print a path from there */
static size_t acpi_device_path_fill(struct device *dev, char *buf,
size_t buf_len, size_t cur)
{
const char *name = acpi_device_name(dev);
size_t next = 0;
/*
* Make sure this name segment will fit, including the path segment
* separator and possible NUL terminator if this is the last segment.
*/
if (!dev || !name || (cur + strlen(name) + 2) > buf_len)
return cur;
/* Walk up the tree to the root device */
if (dev->path.type != DEVICE_PATH_ROOT && dev->bus && dev->bus->dev)
next = acpi_device_path_fill(dev->bus->dev, buf, buf_len, cur);
/* Fill in the path from the root device */
next += snprintf(buf + next, buf_len - next, "%s%s",
dev->path.type == DEVICE_PATH_ROOT ? "" : ".", name);
return next;
}
/*
* Warning: just as with dev_path() this uses a static buffer
* so should not be called mulitple times in one statement
*/
const char *acpi_device_path(struct device *dev)
{
static char buf[DEVICE_PATH_MAX] = {};
if (!dev)
return NULL;
if (acpi_device_path_fill(dev, buf, sizeof(buf), 0) <= 0)
return NULL;
return buf;
}
/* Return the path of the parent device as the ACPI Scope for this device */
const char *acpi_device_scope(struct device *dev)
{
if (!dev || !dev->bus || !dev->bus->dev)
return NULL;
return acpi_device_path(dev->bus->dev);
}
/* Concatentate the device path and provided name suffix */
const char *acpi_device_path_join(struct device *dev, const char *name)
{
static char buf[DEVICE_PATH_MAX] = {};
size_t len;
if (!dev)
return NULL;
/* Build the path of this device */
len = acpi_device_path_fill(dev, buf, sizeof(buf), 0);
if (len <= 0)
return NULL;
/* Ensure there is room for the added name, separator, and NUL */
if ((len + strlen(name) + 2) > sizeof(buf))
return NULL;
snprintf(buf + len, sizeof(buf) - len, ".%s", name);
return buf;
}
/* ACPI 6.1 section 6.4.3.6: Extended Interrupt Descriptor */
void acpi_device_write_interrupt(const struct acpi_irq *irq)
{
void *desc_length;
uint8_t flags;
if (!irq || !irq->pin)
return;
/* This is supported by GpioInt() but not Interrupt() */
if (irq->polarity == IRQ_ACTIVE_BOTH)
return;
/* Byte 0: Descriptor Type */
acpigen_emit_byte(ACPI_DESCRIPTOR_INTERRUPT);
/* Byte 1-2: Length (filled in later) */
desc_length = acpi_device_write_zero_len();
/*
* Byte 3: Flags
* [7:5]: Reserved
* [4]: Wake (0=NO_WAKE 1=WAKE)
* [3]: Sharing (0=EXCLUSIVE 1=SHARED)
* [2]: Polarity (0=HIGH 1=LOW)
* [1]: Mode (0=LEVEL 1=EDGE)
* [0]: Resource (0=PRODUCER 1=CONSUMER)
*/
flags = 1 << 0; /* ResourceConsumer */
if (irq->mode == IRQ_EDGE_TRIGGERED)
flags |= 1 << 1;
if (irq->polarity == IRQ_ACTIVE_LOW)
flags |= 1 << 2;
if (irq->shared == IRQ_SHARED)
flags |= 1 << 3;
if (irq->wake == IRQ_WAKE)
flags |= 1 << 4;
acpigen_emit_byte(flags);
/* Byte 4: Interrupt Table Entry Count */
acpigen_emit_byte(1);
/* Byte 5-8: Interrupt Number */
acpigen_emit_dword(irq->pin);
/* Fill in Descriptor Length (account for len word) */
acpi_device_fill_len(desc_length);
}
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