broadwell: Compute channel disable masks at runtime

Introduce the `SPD_MEMORY_DOWN` macro to indicate that a slot is used
with memory-down. This enables computing the channel disable masks as
the bits for slots where the SPD address is zero. To preserve current
behavior, zero the SPD addresses for memory-down slots afterwards.

Change-Id: I75b7be7c72062d1a26cfc7b09b79de62de0a9cea
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55807
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 22 insertions, 0 deletions

diff --git a/src/soc/intel/broadwell/include/soc/pei_wrapper.h b/src/soc/intel/broadwell/include/soc/pei_wrapper.h
index 4a38a2afa6..cfdb910064 100644
--- a/src/soc/intel/broadwell/include/soc/pei_wrapper.h
+++ b/src/soc/intel/broadwell/include/soc/pei_wrapper.h
@@ -26,6 +26,8 @@ static inline void pei_data_usb3_port(struct pei_data *pei_data, int port,
 	pei_data->usb3_ports[port].fixed_eq = fixed_eq;
 }
 
+#define SPD_MEMORY_DOWN	0xff
+
 void broadwell_fill_pei_data(struct pei_data *pei_data);
 void mainboard_fill_pei_data(struct pei_data *pei_data);
 void mainboard_fill_spd_data(struct pei_data *pei_data);
diff --git a/src/soc/intel/broadwell/raminit.c b/src/soc/intel/broadwell/raminit.c
index 95073d3194..70f38043cd 100644
--- a/src/soc/intel/broadwell/raminit.c
+++ b/src/soc/intel/broadwell/raminit.c
@@ -177,6 +177,17 @@ static void setup_sdram_meminfo(struct pei_data *pei_data)
 	}
 }
 
+/*
+ * 0 = leave channel enabled
+ * 1 = disable dimm 0 on channel
+ * 2 = disable dimm 1 on channel
+ * 3 = disable dimm 0+1 on channel
+ */
+static int make_channel_disabled_mask(const struct pei_data *pd, int ch)
+{
+	return (!pd->spd_addresses[ch + ch] << 0) | (!pd->spd_addresses[ch + ch + 1] << 1);
+}
+
 void perform_raminit(const struct chipset_power_state *const power_state)
 {
 	const int s3resume = power_state->prev_sleep_state == ACPI_S3;
@@ -186,6 +197,15 @@ void perform_raminit(const struct chipset_power_state *const power_state)
 	mainboard_fill_pei_data(&pei_data);
 	mainboard_fill_spd_data(&pei_data);
 
+	/* Calculate unimplemented DIMM slots for each channel */
+	pei_data.dimm_channel0_disabled = make_channel_disabled_mask(&pei_data, 0);
+	pei_data.dimm_channel1_disabled = make_channel_disabled_mask(&pei_data, 1);
+
+	for (size_t i = 0; i < ARRAY_SIZE(pei_data.spd_addresses); i++) {
+		const uint8_t addr = pei_data.spd_addresses[i];
+		pei_data.spd_addresses[i] = addr == SPD_MEMORY_DOWN ? 0 : addr;
+	}
+
 	post_code(0x32);
 
 	timestamp_add_now(TS_INITRAM_START);