[PATCH v2 4/5] firmware: tegra: bpmp: Add MBWT BPMP helpers

From: Aniruddha Rao

Date: Wed Jul 22 2026 - 07:12:57 EST


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@xxxxxxxxxx>
---
Changes since v1:
- Use generic tegra_bpmp_mbwt_*() helper names.
- Fold the helpers into bpmp.c instead of adding a separate source file.
- Drop SoC-specific Kconfig dependencies from the helper patch.
- Return BPMP firmware errors directly.

drivers/firmware/tegra/bpmp-private.h | 7 ++
drivers/firmware/tegra/bpmp.c | 98 +++++++++++++++++++++++++++
2 files changed, 105 insertions(+)

diff --git a/drivers/firmware/tegra/bpmp-private.h b/drivers/firmware/tegra/bpmp-private.h
index 07c3d46abb87..b3770e71020e 100644
--- a/drivers/firmware/tegra/bpmp-private.h
+++ b/drivers/firmware/tegra/bpmp-private.h
@@ -26,4 +26,11 @@ struct tegra_bpmp_ops {
extern const struct tegra_bpmp_ops tegra186_bpmp_ops;
extern const struct tegra_bpmp_ops tegra210_bpmp_ops;

+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 2dcb74a45b59..2cf8490b8b2e 100644
--- a/drivers/firmware/tegra/bpmp.c
+++ b/drivers/firmware/tegra/bpmp.c
@@ -675,6 +675,104 @@ bool tegra_bpmp_mrq_is_supported(struct tegra_bpmp *bpmp, unsigned int mrq)
}
EXPORT_SYMBOL_GPL(tegra_bpmp_mrq_is_supported);

+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)
+ return msg.rx.ret;
+
+ *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)
+ return msg.rx.ret;
+
+ return 0;
+}
+
static void tegra_bpmp_mrq_handle_ping(unsigned int mrq,
struct tegra_bpmp_channel *channel,
void *data)
--
2.43.0