From 10361583b3226bfdca3e4f86b9669a5702fcbadc Mon Sep 17 00:00:00 2001
From: Kilian Krause <kilian.krause@siemens.com>
Date: Tue, 30 Sep 2025 16:12:12 +0200
Subject: [PATCH] mb/siemens/mc_rpl: Add code to wait for legacy devices before
 PCI scan

All mc_rpl boards have, like the mc_apl and mc_ehl variants, legacy
PCI devices which take longer to boot. To ensure their correct
enumeration, a delay is added before the PCI scan starts. The delay
value is provided by hwinfo.

TEST=Built and booted on mc_rpl board. Verified legacy PCI devices
enumerate correctly after delay implementation. Log excerpt while
testing function:

```
[INFO ]  tlcl2_extend: response is 0x0
[DEBUG]  TPM: Digest of `CBFS: hwinfo.hex` to PCR 3 measured
[NOTE ]  Wait remaining 6595702 of 10000000 us for legacy devices...done!
[DEBUG]  BS: BS_DEV_ENUMERATE entry times (exec / console): 6597 / 64 ms
[INFO ]  Enumerating buses...
```

Change-Id: I97885a7cf060bc69c7fef75a9fa917bc8a176582
Signed-off-by: Kilian Krause <kilian.krause@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/89393
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
---
 src/mainboard/siemens/mc_rpl/mainboard.c | 30 ++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/src/mainboard/siemens/mc_rpl/mainboard.c b/src/mainboard/siemens/mc_rpl/mainboard.c
index 69670aa0ec..44b11a0825 100644
--- a/src/mainboard/siemens/mc_rpl/mainboard.c
+++ b/src/mainboard/siemens/mc_rpl/mainboard.c
@@ -2,6 +2,7 @@
 
 #include <baseboard/gpio.h>
 #include <baseboard/variants.h>
+#include <bootstate.h>
 #include <cpu/x86/msr.h>
 #include <device/device.h>
 #include <device/pci_def.h>
@@ -14,6 +15,8 @@
 #include <soc/ramstage.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <timer.h>
+#include <timestamp.h>
 
 #define MAX_PATH_DEPTH		12
 #define MAX_NUM_MAPPINGS	10
@@ -91,6 +94,31 @@ enum cb_err mainboard_get_mac_address(struct device *dev, uint8_t mac[MAC_ADDR_L
 	return CB_ERR;
 }
 
+static void wait_for_legacy_dev(void *unused)
+{
+	uint32_t legacy_delay_us, 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_us,
+			sizeof(legacy_delay_us)) != sizeof(legacy_delay_us))
+		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_us)
+		return;
+	stopwatch_init_msecs_expire(&sw, (legacy_delay_us - us_since_boot) / 1000);
+	printk(BIOS_NOTICE, "Wait remaining %d of %d us for legacy devices...",
+			legacy_delay_us - us_since_boot, legacy_delay_us);
+	stopwatch_wait_until_expired(&sw);
+	printk(BIOS_NOTICE, " done!\n");
+}
+
 void mainboard_silicon_init_params(FSP_S_CONFIG *params)
 {
 	params->Eist = 0;
@@ -130,3 +158,5 @@ struct chip_operations mainboard_ops = {
 	.init = mainboard_init,
 	.final = mainboard_final,
 };
+
+BOOT_STATE_INIT_ENTRY(BS_DEV_ENUMERATE, BS_ON_ENTRY, wait_for_legacy_dev, NULL);