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authorAndrey Petrov <andrey.petrov@intel.com>2016-04-04 16:10:40 -0700
committerAaron Durbin <adurbin@chromium.org>2016-04-13 16:08:09 +0200
commit28c78abaf72b591092c7ec586e4e42492f49082e (patch)
tree68d5e73a5834fd77cbd1dfcea9ab2b79e99cb82a
parent108cd0e16d072bef918a3edac2a0e2703f47daba (diff)
downloadcoreboot-28c78abaf72b591092c7ec586e4e42492f49082e.tar.xz
soc/intel/apollolake: Reserve IMRs (Isolated Memory Regions)
Certain security features on the platform use IMRs. Unfortunately this memory is unusable for OS or firware. This patch marks IMR regions as unusable. Change-Id: I4803c41c699a9cb3349de2b7e0910a0a37cf8e59 Signed-off-by: Andrey Petrov <andrey.petrov@intel.com> Reviewed-on: https://review.coreboot.org/14245 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins)
-rw-r--r--src/soc/intel/apollolake/include/soc/northbridge.h7
-rw-r--r--src/soc/intel/apollolake/northbridge.c47
2 files changed, 53 insertions, 1 deletions
diff --git a/src/soc/intel/apollolake/include/soc/northbridge.h b/src/soc/intel/apollolake/include/soc/northbridge.h
index 4a071cb788..b68bc933e9 100644
--- a/src/soc/intel/apollolake/include/soc/northbridge.h
+++ b/src/soc/intel/apollolake/include/soc/northbridge.h
@@ -23,4 +23,11 @@
#define TOLUD 0xbc /* Top of Low Used Memory */
#define TOUUD 0xa8 /* Top of Upper Usable DRAM */
+/* IMR registers are found under MCHBAR. */
+#define MCHBAR_IMR0BASE 0x6870
+#define MCHBAR_IMR0MASK 0x6874
+#define MCH_IMR_PITCH 0x20
+#define MCH_NUM_IMRS 20
+
+
#endif /* _SOC_APOLLOLAKE_NORTHBRIDGE_H_ */
diff --git a/src/soc/intel/apollolake/northbridge.c b/src/soc/intel/apollolake/northbridge.c
index 7d29c9ed45..1a46b61ea9 100644
--- a/src/soc/intel/apollolake/northbridge.c
+++ b/src/soc/intel/apollolake/northbridge.c
@@ -43,6 +43,47 @@ static int mc_add_fixed_mmio_resources(device_t dev, int index)
return index;
}
+static bool is_imr_enabled(uint32_t imr_base_reg)
+{
+ return !!(imr_base_reg & (1 << 31));
+}
+
+static void imr_resource(device_t dev, int idx, uint32_t base, uint32_t mask)
+{
+ uint32_t base_k, size_k;
+ /* Bits 28:0 encode the base address bits 38:10, hence the KiB unit. */
+ base_k = (base & 0x0fffffff);
+ /* Bits 28:0 encode the AND mask used for comparison, in KiB. */
+ size_k = ((~mask & 0x0fffffff) + 1);
+ /*
+ * IMRs sit in lower DRAM. Mark them cacheable, otherwise we run
+ * out of MTRRs. Memory reserved by IMRs is not usable for host
+ * so mark it reserved.
+ */
+ reserved_ram_resource(dev, idx, base_k, size_k);
+}
+
+static int mc_add_imr_resources(device_t dev, int index)
+{
+ uint8_t *mchbar;
+ size_t i, imr_offset;
+ uint32_t base, mask;
+
+ mchbar = (void *)(ALIGN_DOWN(get_bar(dev, MCHBAR), 32*KiB));
+
+ for (i = 0; i < MCH_NUM_IMRS; i ++) {
+ imr_offset = i * MCH_IMR_PITCH;
+ base = read32(mchbar + imr_offset + MCHBAR_IMR0BASE);
+ mask = read32(mchbar + imr_offset + MCHBAR_IMR0MASK);
+
+ if (is_imr_enabled(base)) {
+ imr_resource(dev, index++, base, mask);
+ }
+ }
+
+ return index;
+}
+
static int mc_add_dram_resources(device_t dev, int index)
{
@@ -99,7 +140,11 @@ static void northbridge_read_resources(device_t dev)
index = mc_add_fixed_mmio_resources(dev, index);
/* Calculate and add DRAM resources. */
- mc_add_dram_resources(dev, index);
+ index = mc_add_dram_resources(dev, index);
+
+ /* Add the isolated memory ranges (IMRs). */
+ mc_add_imr_resources(dev, index);
+
}
static struct device_operations northbridge_ops = {