Change in coreboot[master]: mb/siemens/mc_ehl: Add code to wait for legacy devices before PCI scan

[Paul Fagerburg (Code Review)]

Paul Fagerburg has submitted this change. ( https://review.coreboot.org/c/coreboot/+/56631 )

Change subject: mb/siemens/mc_ehl: Add code to wait for legacy devices before PCI scan
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mb/siemens/mc_ehl: Add code to wait for legacy devices before PCI scan

Boards based on mc_ehl have, just like some mc_apl variants, legacy
devices on the PCI bus which take longer to boot. In order to ensure
that they will be enumerated correctly wait for them to come up before
PCI scan starts.

TEST=Checked that the new message is visible in the log.

Change-Id: If2f935b69ddaa9364566deacfada5e7d41fcdabd
Signed-off-by: Werner Zeh 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56631
Reviewed-by: Mario Scheithauer 
Reviewed-by: Paul Menzel 
Tested-by: build bot (Jenkins) 
---
M src/mainboard/siemens/mc_ehl/mainboard.c
1 file changed, 30 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Paul Menzel: Looks good to me, but someone else must approve
  Mario Scheithauer: Looks good to me, approved

diff --git a/src/mainboard/siemens/mc_ehl/mainboard.c b/src/mainboard/siemens/mc_ehl/mainboard.c
index fc7d31f..4cc5490 100644
--- a/src/mainboard/siemens/mc_ehl/mainboard.c
+++ b/src/mainboard/siemens/mc_ehl/mainboard.c
@@ -1,12 +1,15 @@
 /* SPDX-License-Identifier: GPL-2.0-only */

#include <baseboard/variants.h>
+#include <bootstate.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <hwilib.h>
 #include <i210.h>
 #include <soc/gpio.h>
 #include <string.h>
+#include <timer.h>
+#include <timestamp.h>

#define MAX_PATH_DEPTH		12
 #define MAX_NUM_MAPPINGS	10
@@ -83,6 +86,31 @@
    return CB_ERR;
 }

+static void wait_for_legacy_dev(void *unused)
+{
+	uint32_t legacy_delay, us_since_boot;
+	struct stopwatch sw;
+
+	/* Open main hwinfo block. */
+	if (hwilib_find_blocks("hwinfo.hex") != CB_SUCCESS)
+		return;
+
+	/* Get legacy delay parameter from hwinfo. */
+	if (hwilib_get_field(LegacyDelay, (uint8_t *) &legacy_delay,
+			      sizeof(legacy_delay)) != sizeof(legacy_delay))
+		return;
+
+	us_since_boot = get_us_since_boot();
+	/* No need to wait if the time since boot is already long enough.*/
+	if (us_since_boot > legacy_delay)
+		return;
+	stopwatch_init_msecs_expire(&sw, (legacy_delay - us_since_boot) / 1000);
+	printk(BIOS_NOTICE, "Wait remaining %d of %d us for legacy devices...",
+			legacy_delay - us_since_boot, legacy_delay);
+	stopwatch_wait_until_expired(&sw);
+	printk(BIOS_NOTICE, "done!\n");
+}
+
 static void mainboard_init(void *chip_info)
 {
    const struct pad_config *pads;
@@ -95,3 +123,5 @@
 struct chip_operations mainboard_ops = {
    .init = mainboard_init,
 };
+
+BOOT_STATE_INIT_ENTRY(BS_DEV_ENUMERATE, BS_ON_ENTRY, wait_for_legacy_dev, NULL);