[PATCH v5 4/5] firmware: tegra: bpmp: Add MBWT BPMP helpers

[Aniruddha Rao <anrao@nvidia.com>]

Add helper functions that send MBWT requests to BPMP firmware.

The helpers implement the GET_BW and SET_BW operations.

They also provide a QUERY_ABI-based probe for command availability.

Signed-off-by: Aniruddha Rao <anrao@nvidia.com>
---
Changes since v4:
- No change.

Changes since v3:
- No change.

Changes since v2:
- Move the MBWT helpers near probe.
- Explain why the MBWT helpers are needed in the commit message.

Changes since v1:
- Use generic MBWT helper names.
- Fold the MBWT helpers into bpmp.c.
- Drop MBWT Kconfig dependencies.
- Add firmware error handling for MBWT requests.

 drivers/firmware/tegra/bpmp-private.h |   7 ++
 drivers/firmware/tegra/bpmp.c         | 111 +++++++++++++++++++++++++-
 2 files changed, 117 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/tegra/bpmp-private.h b/drivers/firmware/tegra/bpmp-private.h
index 163b1c82d445..f0a7d6254bdc 100644
--- a/drivers/firmware/tegra/bpmp-private.h
+++ b/drivers/firmware/tegra/bpmp-private.h
@@ -32,4 +32,11 @@ int tegra_bpmp_init_ping(struct tegra_bpmp *bpmp);
 void tegra_bpmp_deinit_ping(struct tegra_bpmp *bpmp);
 int tegra_bpmp_init_dt_providers(struct tegra_bpmp *bpmp);
 
+bool tegra_bpmp_mbwt_cmd_is_supported(struct tegra_bpmp *bpmp,
+				      unsigned int cmd_code);
+int tegra_bpmp_mbwt_get(struct tegra_bpmp *bpmp, unsigned int instance,
+			unsigned int vc_type, unsigned int *bandwidth);
+int tegra_bpmp_mbwt_set(struct tegra_bpmp *bpmp, unsigned int instance,
+			unsigned int vc_type, unsigned int bandwidth);
+
 #endif
diff --git a/drivers/firmware/tegra/bpmp.c b/drivers/firmware/tegra/bpmp.c
index bd8564865638..f2b739977f13 100644
--- a/drivers/firmware/tegra/bpmp.c
+++ b/drivers/firmware/tegra/bpmp.c
@@ -844,8 +844,117 @@ void tegra_bpmp_handle_rx(struct tegra_bpmp *bpmp)
 	spin_unlock(&bpmp->lock);
 }
 
-int tegra_bpmp_init_channels(struct tegra_bpmp *bpmp)
 
+/*
+ * MBWT controls are not exposed through ordinary host MMIO and are accessed
+ * through BPMP firmware requests. These helpers provide the request wrappers
+ * used by bandwidth control callers.
+ */
+bool tegra_bpmp_mbwt_cmd_is_supported(struct tegra_bpmp *bpmp,
+				      unsigned int cmd_code)
+{
+	struct mrq_sochub_mbwt_request request = {
+		.cmd = CMD_SOCHUB_MBWT_QUERY_ABI,
+		.query_abi.cmd_code = cmd_code,
+	};
+	struct tegra_bpmp_message msg = {
+		.mrq = MRQ_SOCHUB_MBWT,
+		.tx = {
+			.data = &request,
+			.size = sizeof(request),
+		},
+	};
+	int err;
+
+	err = tegra_bpmp_transfer(bpmp, &msg);
+	if (err || msg.rx.ret)
+		return false;
+
+	return true;
+}
+
+int tegra_bpmp_mbwt_get(struct tegra_bpmp *bpmp, unsigned int instance,
+			unsigned int vc_type, unsigned int *bandwidth)
+{
+	struct mrq_sochub_mbwt_request request = {
+		.cmd = CMD_SOCHUB_MBWT_GET_BW,
+		.get_bw = {
+			.instance = instance,
+			.vc_type = vc_type,
+		},
+	};
+	struct mrq_sochub_mbwt_response response = {};
+	struct tegra_bpmp_message msg = {
+		.mrq = MRQ_SOCHUB_MBWT,
+		.tx = {
+			.data = &request,
+			.size = sizeof(request),
+		},
+		.rx = {
+			.data = &response,
+			.size = sizeof(response),
+		},
+	};
+	int err;
+
+	if (!bandwidth)
+		return -EINVAL;
+
+	err = tegra_bpmp_transfer(bpmp, &msg);
+	if (err) {
+		dev_err(bpmp->dev, "MBWT get bandwidth transfer failed: %d\n",
+			err);
+		return err;
+	}
+
+	if (msg.rx.ret) {
+		dev_err(bpmp->dev, "MBWT get bandwidth failed: BPMP error %d\n",
+			msg.rx.ret);
+		return -EIO;
+	}
+
+	*bandwidth = response.get_bw.bw;
+
+	return 0;
+}
+
+int tegra_bpmp_mbwt_set(struct tegra_bpmp *bpmp, unsigned int instance,
+			unsigned int vc_type, unsigned int bandwidth)
+{
+	struct mrq_sochub_mbwt_request request = {
+		.cmd = CMD_SOCHUB_MBWT_SET_BW,
+		.set_bw = {
+			.instance = instance,
+			.vc_type = vc_type,
+			.bw = bandwidth,
+		},
+	};
+	struct tegra_bpmp_message msg = {
+		.mrq = MRQ_SOCHUB_MBWT,
+		.tx = {
+			.data = &request,
+			.size = sizeof(request),
+		},
+	};
+	int err;
+
+	err = tegra_bpmp_transfer(bpmp, &msg);
+	if (err) {
+		dev_err(bpmp->dev, "MBWT set bandwidth transfer failed: %d\n",
+			err);
+		return err;
+	}
+
+	if (msg.rx.ret) {
+		dev_err(bpmp->dev, "MBWT set bandwidth failed: BPMP error %d\n",
+			msg.rx.ret);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+int tegra_bpmp_init_channels(struct tegra_bpmp *bpmp)
 {
 	size_t size;
 
-- 
2.43.0