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authorAngel Pons <th3fanbus@gmail.com>2022-10-07 18:24:58 +0200
committerMartin L Roth <gaumless@gmail.com>2022-10-22 16:39:05 +0000
commit436f1c471a576d36101d7ef42e29d2c4e28950e6 (patch)
tree3354b40e1b314d5a8aeeeef06efd3e2309c4e12b /src
parent036b16b884725c044c82724c005b823a8663c970 (diff)
mb/siemens/mc_apl*: Enable early PCI bridge before FSP-M
Apollo Lake seems to start with PCIe root ports unusable/uninitialized before FspMemoryInit() is called and FSP-M properly initializes these root ports. However, we need the root ports accessible before FspMemoryInit() in certain cases, such as emitting POST codes through a PCIe device. For the initialization to happen properly, certain register writes specified in Apollo Lake IAFW BIOS spec, vol. 2 (#559811), chapter 3.3.1 have to be done. BUG=none TEST=Boot on siemens/mc_apl2 with NC_FPGA_POST_CODE enabled and check that the POST codes are emitted before FspMemoryInit(). Change-Id: If782bfdd5f499dd47c085a0a16b4b15832bc040e Signed-off-by: Angel Pons <th3fanbus@gmail.com> Signed-off-by: Jan Samek <jan.samek@siemens.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/68223 Reviewed-by: Werner Zeh <werner.zeh@siemens.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src')
-rw-r--r--src/mainboard/siemens/mc_apl1/bootblock.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/src/mainboard/siemens/mc_apl1/bootblock.c b/src/mainboard/siemens/mc_apl1/bootblock.c
index a858f1b048..7aab2a0f07 100644
--- a/src/mainboard/siemens/mc_apl1/bootblock.c
+++ b/src/mainboard/siemens/mc_apl1/bootblock.c
@@ -2,7 +2,26 @@
#include <baseboard/variants.h>
#include <bootblock_common.h>
+#include <device/pci_def.h>
+#include <device/pci_ops.h>
#include <intelblocks/gpio.h>
+#include <types.h>
+
+static void pcie_rp_early_enable(void)
+{
+ const pci_devfn_t rp_dev = PCI_DEV(0, CONFIG_EARLY_PCI_BRIDGE_DEVICE,
+ CONFIG_EARLY_PCI_BRIDGE_FUNCTION);
+
+ if (pci_read_config16(rp_dev, PCI_VENDOR_ID) == 0xffff)
+ return;
+
+ /*
+ * Needs to be done "immediately after PERST# de-assertion"
+ * as per IAFW BIOS spec volume 2 (doc 559811)
+ */
+ pci_and_config32(rp_dev, 0x338, ~(1 << 26)); /* BLKDQDA */
+ pci_and_config32(rp_dev, 0xf4, ~(1 << 2)); /* BLKPLLEN */
+}
void bootblock_mainboard_early_init(void)
{
@@ -11,4 +30,8 @@ void bootblock_mainboard_early_init(void)
pads = variant_early_gpio_table(&num);
gpio_configure_pads(pads, num);
+
+ /* Enable the PCIe root port when used before FSP-M MemoryInit() */
+ if (CONFIG(EARLY_PCI_BRIDGE))
+ pcie_rp_early_enable();
}