From 10f8da4a13750852df7e3ecc08215f98a91cf0f4 Mon Sep 17 00:00:00 2001
From: Christian Helmuth <christian.helmuth@genode-labs.com>
Date: Fri, 21 Oct 2022 15:00:33 +0200
Subject: [PATCH] pci_decode: fixup Intel LPSS (I2C) PCI BARs

Discovered on Tigerlake (Fujitsu U7411) and Alderlake (Framework Gen12)
notebook devices.

Issue #5195
---
 repos/os/src/app/pci_decode/main.cc | 30 +++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/repos/os/src/app/pci_decode/main.cc b/repos/os/src/app/pci_decode/main.cc
index 3ab186d3f6..01d36c3aa4 100644
--- a/repos/os/src/app/pci_decode/main.cc
+++ b/repos/os/src/app/pci_decode/main.cc
@@ -75,6 +75,32 @@ struct Main
 };
 
 
+/*
+ * If PCI devices happen to miss complete configuration after boot, i.e., have
+ * a zero base address, we report a fixed address for known devices.
+ * platform_drv in turn, will setup the address from the report when enabling
+ * the device.
+ *
+ * The issue was discovered with Intel LPSS devices in Fujitsu notebooks.
+ *
+ * XXX static fixup list should be replaced by dynamic mapping of BAR
+ */
+static uint64_t fixup_bar_base_address(Bdf bdf, unsigned bar, uint64_t addr, size_t size)
+{
+	auto base_address = addr;
+
+	/* Intel LPSS (I2C) devices - values taken from Linux boot */
+	if (bdf == Bdf { 0, 0x15, 0 } && bar == 0) base_address = 0x4017000000;
+	if (bdf == Bdf { 0, 0x15, 1 } && bar == 0) base_address = 0x4017001000;
+	if (bdf == Bdf { 0, 0x15, 2 } && bar == 0) base_address = 0x4017001000;
+	if (bdf == Bdf { 0, 0x15, 3 } && bar == 0) base_address = 0x4017002000;
+
+	if (addr != base_address)
+		log(bdf, " remap MEM BAR", bar, " ", Hex_range(addr, size), " to ", Hex(base_address));
+
+	return base_address;
+}
+
 /*
  * The bus and function parsers return either the current bus number or the
  * subordinate bus number (highest bus number of all of the busses that can be
@@ -153,6 +179,10 @@ bus_t Main::parse_pci_function(Bdf             bdf,
 		cfg.for_each_bar([&] (uint64_t addr, uint64_t size,
 		                      unsigned bar, bool pf)
 		{
+			addr = fixup_bar_base_address(bdf, bar, addr, size);
+			if (!addr)
+				warning(bdf, " MEM BAR", bar, " ", Hex_range(addr, size),
+				        " has invalid base address - consider pci-fixup in parse_pci_function()");
 			gen.node("io_mem", [&]
 			{
 				gen.attribute("pci_bar", bar);