1 files changed, 218 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dpcd.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpcd.c
new file mode 100644
index 000000000000..fe234760a0f5
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpcd.c
@@ -0,0 +1,218 @@
+#include <inc/core_status.h>
+#include <dc_link.h>
+#include <inc/link_hwss.h>
+#include <inc/link_dpcd.h>
+#include "drm/drm_dp_helper.h"
+#include <dc_dp_types.h>
+#include "dm_helpers.h"
+
+#define END_ADDRESS(start, size) (start + size - 1)
+#define ADDRESS_RANGE_SIZE(start, end) (end - start + 1)
+struct dpcd_address_range {
+	uint32_t start;
+	uint32_t end;
+};
+
+static enum dc_status internal_link_read_dpcd(
+	struct dc_link *link,
+	uint32_t address,
+	uint8_t *data,
+	uint32_t size)
+{
+	if (!link->aux_access_disabled &&
+			!dm_helpers_dp_read_dpcd(link->ctx,
+			link, address, data, size)) {
+		return DC_ERROR_UNEXPECTED;
+	}
+
+	return DC_OK;
+}
+
+static enum dc_status internal_link_write_dpcd(
+	struct dc_link *link,
+	uint32_t address,
+	const uint8_t *data,
+	uint32_t size)
+{
+	if (!link->aux_access_disabled &&
+			!dm_helpers_dp_write_dpcd(link->ctx,
+			link, address, data, size)) {
+		return DC_ERROR_UNEXPECTED;
+	}
+
+	return DC_OK;
+}
+
+/*
+ * Partition the entire DPCD address space
+ * XXX: This partitioning must cover the entire DPCD address space,
+ * and must contain no gaps or overlapping address ranges.
+ */
+static const struct dpcd_address_range mandatory_dpcd_partitions[] = {
+	{ 0, DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR1) - 1},
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR1), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR2) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR2), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR3) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR3), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR4) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR4), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR5) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR5), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR6) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR6), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR7) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR7), DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR8) - 1 },
+	{ DP_TRAINING_PATTERN_SET_PHY_REPEATER(DP_PHY_LTTPR8), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR1) - 1 },
+	/*
+	 * The FEC registers are contiguous
+	 */
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR1), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR1) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR2), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR2) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR3), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR3) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR4), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR4) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR5), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR5) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR6), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR6) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR7), DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR7) - 1 },
+	{ DP_FEC_STATUS_PHY_REPEATER(DP_PHY_LTTPR8), DP_LTTPR_MAX_ADD },
+	/* all remaining DPCD addresses */
+	{ DP_LTTPR_MAX_ADD + 1, DP_DPCD_MAX_ADD } };
+
+static inline bool do_addresses_intersect_with_range(
+		const struct dpcd_address_range *range,
+		const uint32_t start_address,
+		const uint32_t end_address)
+{
+	return start_address <= range->end && end_address >= range->start;
+}
+
+static uint32_t dpcd_get_next_partition_size(const uint32_t address, const uint32_t size)
+{
+	const uint32_t end_address = END_ADDRESS(address, size);
+	uint32_t partition_iterator = 0;
+
+	/*
+	 * find current partition
+	 * this loop spins forever if partition map above is not surjective
+	 */
+	while (!do_addresses_intersect_with_range(&mandatory_dpcd_partitions[partition_iterator],
+				address, end_address))
+		partition_iterator++;
+	if (end_address < mandatory_dpcd_partitions[partition_iterator].end)
+		return size;
+	return ADDRESS_RANGE_SIZE(address, mandatory_dpcd_partitions[partition_iterator].end);
+}
+
+/*
+ * Ranges of DPCD addresses that must be read in a single transaction
+ * XXX: Do not allow any two address ranges in this array to overlap
+ */
+static const struct dpcd_address_range mandatory_dpcd_blocks[] = {
+	{ DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV, DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT }};
+
+/*
+ * extend addresses to read all mandatory blocks together
+ */
+static void dpcd_extend_address_range(
+		const uint32_t in_address,
+		uint8_t * const in_data,
+		const uint32_t in_size,
+		uint32_t *out_address,
+		uint8_t **out_data,
+		uint32_t *out_size)
+{
+	const uint32_t end_address = END_ADDRESS(in_address, in_size);
+	const struct dpcd_address_range *addr_range;
+	struct dpcd_address_range new_addr_range;
+	uint32_t i;
+
+	new_addr_range.start = in_address;
+	new_addr_range.end = end_address;
+	for (i = 0; i < ARRAY_SIZE(mandatory_dpcd_blocks); i++) {
+		addr_range = &mandatory_dpcd_blocks[i];
+		if (addr_range->start <= in_address && addr_range->end >= in_address)
+			new_addr_range.start = addr_range->start;
+
+		if (addr_range->start <= end_address && addr_range->end >= end_address)
+			new_addr_range.end = addr_range->end;
+	}
+	*out_address = in_address;
+	*out_size = in_size;
+	*out_data = in_data;
+	if (new_addr_range.start != in_address || new_addr_range.end != end_address) {
+		*out_address = new_addr_range.start;
+		*out_size = ADDRESS_RANGE_SIZE(new_addr_range.start, new_addr_range.end);
+		*out_data = kzalloc(*out_size * sizeof(**out_data), GFP_KERNEL);
+	}
+}
+
+/*
+ * Reduce the AUX reply down to the values the caller requested
+ */
+static void dpcd_reduce_address_range(
+		const uint32_t extended_address,
+		uint8_t * const extended_data,
+		const uint32_t extended_size,
+		const uint32_t reduced_address,
+		uint8_t * const reduced_data,
+		const uint32_t reduced_size)
+{
+	const uint32_t reduced_end_address = END_ADDRESS(reduced_address, reduced_size);
+	const uint32_t extended_end_address = END_ADDRESS(extended_address, extended_size);
+	const uint32_t offset = reduced_address - extended_address;
+
+	if (extended_end_address == reduced_end_address && extended_address == reduced_address)
+		return; /* extended and reduced address ranges point to the same data */
+
+	memcpy(&extended_data[offset], reduced_data, reduced_size);
+	kfree(extended_data);
+}
+
+enum dc_status core_link_read_dpcd(
+	struct dc_link *link,
+	uint32_t address,
+	uint8_t *data,
+	uint32_t size)
+{
+	uint32_t extended_address;
+	uint32_t partitioned_address;
+	uint8_t *extended_data;
+	uint32_t extended_size;
+	/* size of the remaining partitioned address space */
+	uint32_t size_left_to_read;
+	enum dc_status status;
+	/* size of the next partition to be read from */
+	uint32_t partition_size;
+	uint32_t data_index = 0;
+
+	dpcd_extend_address_range(address, data, size, &extended_address, &extended_data, &extended_size);
+	partitioned_address = extended_address;
+	size_left_to_read = extended_size;
+	while (size_left_to_read) {
+		partition_size = dpcd_get_next_partition_size(partitioned_address, size_left_to_read);
+		status = internal_link_read_dpcd(link, partitioned_address, &extended_data[data_index], partition_size);
+		if (status != DC_OK)
+			break;
+		partitioned_address += partition_size;
+		data_index += partition_size;
+		size_left_to_read -= partition_size;
+	}
+	dpcd_reduce_address_range(extended_address, extended_data, extended_size, address, data, size);
+	return status;
+}
+
+enum dc_status core_link_write_dpcd(
+	struct dc_link *link,
+	uint32_t address,
+	const uint8_t *data,
+	uint32_t size)
+{
+	uint32_t partition_size;
+	uint32_t data_index = 0;
+	enum dc_status status;
+
+	while (size) {
+		partition_size = dpcd_get_next_partition_size(address, size);
+		status = internal_link_write_dpcd(link, address, &data[data_index], partition_size);
+		if (status != DC_OK)
+			break;
+		address += partition_size;
+		data_index += partition_size;
+		size -= partition_size;
+	}
+	return status;
+}