I configured TF-A to UART4, Optee to UART4, Uboot to USART1 and added printf messages to uboot source code.
/* serial-uclass.c */
#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
static int serial_check_stdout(const void *blob, struct udevice **devp)
{
int node = -1;
const char *str, *p, *name;
int namelen;
/* Check for a chosen console */
str = fdtdec_get_chosen_prop(blob, "stdout-path");
if (str) {
p = strchr(str, ':');
namelen = p ? p - str : strlen(str);
node = fdt_path_offset_namelen(blob, str, namelen);
if (node < 0) {
/*
* Deal with things like
* stdout-path = "serial0:115200n8";
*
* We need to look up the alias and then follow it to
* the correct node.
*/
name = fdt_get_alias_namelen(blob, str, namelen);
if (name)
node = fdt_path_offset(blob, name);
}
}
if (node < 0)
node = fdt_path_offset(blob, "console");
if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, devp))
return 0;
/*
* If the console is not marked to be bound before relocation, bind it
* anyway.
*/
if (node > 0 && !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
devp, NULL, false)) {
if (device_get_uclass_id(*devp) == UCLASS_SERIAL) {
printf("\nserial_check_stdout: probing %s\n", (*devp)->name);
int result = !device_probe(*devp);
printf("\nserial_check_stdout: finished probing %s\n", (*devp)->name);
if (result)
return 0;
}
}
return -ENODEV;
}
/* device.c */
int device_probe(struct udevice *dev)
{
const struct driver *drv;
int ret;
if (!dev)
return -EINVAL;
if (dev_get_flags(dev) & DM_FLAG_ACTIVATED)
return 0;
ret = device_notify(dev, EVT_DM_PRE_PROBE);
if (ret)
return ret;
drv = dev->driver;
assert(drv);
printf("\ndevice_probe: probing %s\n", dev->name);
ret = device_of_to_plat(dev);
if (ret)
goto fail;
/* Ensure all parents are probed */
if (dev->parent) {
printf("\ndevice_probe: about to probe %s\n", dev->parent->name);
ret = device_probe(dev->parent);
printf("\ndevice_probe: probed %s, exit code %i\n", dev->parent->name, ret);
if (ret)
goto fail;
/*
* The device might have already been probed during
* the call to device_probe() on its parent device
* (e.g. PCI bridge devices). Test the flags again
* so that we don't mess up the device.
*/
if (dev_get_flags(dev) & DM_FLAG_ACTIVATED)
return 0;
}
dev_or_flags(dev, DM_FLAG_ACTIVATED);
if (CONFIG_IS_ENABLED(POWER_DOMAIN) && dev->parent &&
(device_get_uclass_id(dev) != UCLASS_POWER_DOMAIN) &&
!(drv->flags & DM_FLAG_DEFAULT_PD_CTRL_OFF)) {
ret = dev_power_domain_on(dev);
if (ret)
goto fail;
}
/*
* Process pinctrl for everything except the root device, and
* continue regardless of the result of pinctrl. Don't process pinctrl
* settings for pinctrl devices since the device may not yet be
* probed.
*
* This call can produce some non-intuitive results. For example, on an
* x86 device where dev is the main PCI bus, the pinctrl device may be
* child or grandchild of that bus, meaning that the child will be
* probed here. If the child happens to be the P2SB and the pinctrl
* device is a child of that, then both the pinctrl and P2SB will be
* probed by this call. This works because the DM_FLAG_ACTIVATED flag
* is set just above. However, the PCI bus' probe() method and
* associated uclass methods have not yet been called.
*/
if (dev->parent && device_get_uclass_id(dev) != UCLASS_PINCTRL) {
ret = pinctrl_select_state(dev, "default");
if (ret && ret != -ENOSYS)
log_debug("Device '%s' failed to configure default pinctrl: %d (%s)\n",
dev->name, ret, errno_str(ret));
}
if (CONFIG_IS_ENABLED(IOMMU) && dev->parent &&
(device_get_uclass_id(dev) != UCLASS_IOMMU)) {
ret = dev_iommu_enable(dev);
if (ret)
goto fail;
}
ret = device_get_dma_constraints(dev);
if (ret)
goto fail;
ret = uclass_pre_probe_device(dev);
if (ret)
goto fail;
if (dev->parent && dev->parent->driver->child_pre_probe) {
ret = dev->parent->driver->child_pre_probe(dev);
if (ret)
goto fail;
}
/* Only handle devices that have a valid ofnode */
if (dev_has_ofnode(dev)) {
/*
* Process 'assigned-{clocks/clock-parents/clock-rates}'
* properties
*/
ret = clk_set_defaults(dev, CLK_DEFAULTS_PRE);
if (ret)
goto fail;
}
if (drv->probe) {
ret = drv->probe(dev);
if (ret)
goto fail;
}
ret = uclass_post_probe_device(dev);
if (ret)
goto fail_uclass;
if (dev->parent && device_get_uclass_id(dev) == UCLASS_PINCTRL) {
ret = pinctrl_select_state(dev, "default");
if (ret && ret != -ENOSYS)
log_debug("Device '%s' failed to configure default pinctrl: %d (%s)\n",
dev->name, ret, errno_str(ret));
}
ret = device_notify(dev, EVT_DM_POST_PROBE);
if (ret)
return ret;
printf("\ndevice_probe: probing %s finished with 0 code\n", dev->name);
return 0;
fail_uclass:
if (device_remove(dev, DM_REMOVE_NORMAL)) {
dm_warn("%s: Device '%s' failed to remove on error path\n",
__func__, dev->name);
}
fail:
dev_bic_flags(dev, DM_FLAG_ACTIVATED);
device_free(dev);
printf("\ndevice_probe: reached fail while probing %s\n", dev->name);
return ret;
}
/* log.h */
//#ifdef LOG_DEBUG
#define _LOG_DEBUG LOGL_FORCE_DEBUG
#ifndef DEBUG
#define DEBUG
#endif
//#else
//#define _LOG_DEBUG 0
//#endif
/* stm32mp15_defconfig */
CONFIG_LOG=y
CONFIG_LOG_CONSOLE=y
CONFIG_LOG_MAX_LEVEL=7
CONFIG_DEBUG_UART_BOARD_INIT=y
CONFIG_DEBUG_UART=y
CONFIG_DEBUG_UART_STM32=y
CONFIG_DEBUG_UART_CLOCK=64000000
CONFIG_DEBUG_UART_SKIP_INIT=y
CONFIG_TRACE_EARLY=y
CONFIG_CMD_TRACE=y
For log_uboot_uart4.txt I removed modifications in log.h because there was too much verbosity.
