siemens/mc_apl1: Add delay to wait for legacy devices

There are old legacy onboard devices which are too slow for a coreboot
boot with log level BIOS_ERR. In this case coreboot is so fast that these
devices do not have enough time to become visible on the PCI bus and
this in turn leads to missing resource allocation for this devices. The
most generic way to work around this problem on existing hardware is to
introduce a delay right before the PCI enumeration starts. The needed
delay time depends on the hardware and will therefore be get from
hwinfo.

Change-Id: Ia91babc81e3a347bbc498c3def97b2ea70e10922
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/21518
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>

src/mainboard/siemens/mc_apl1/mainboard.c

@@ -23,6 +23,9 @@
 #include <intelblocks/lpc_lib.h>
 #include <soc/pci_devs.h>
 #include <string.h>
+#include <bootstate.h>
+#include <timer.h>
+#include <timestamp.h>
 #include "brd_gpio.h"
 #include "ptn3460.h"
 
@@ -141,6 +144,34 @@ static void mainboard_final(void *chip_info)
 	}
 }
 
+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);
+	while (!stopwatch_expired(&sw))
+		;
+	printk(BIOS_NOTICE, "done!\n");
+}
+
+BOOT_STATE_INIT_ENTRY(BS_DEV_ENUMERATE, BS_ON_ENTRY, wait_for_legacy_dev, NULL);
+
 struct chip_operations mainboard_ops = {
 	.init = mainboard_init,
 	.final = mainboard_final,