linux-kernel - [PATCH v4 11/11] wifi: ath11k: Add support for MHI bandwidth scaling

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Message-Id: <20250609-mhi_bw_up-v4-11-3faa8fe92b05@qti.qualcomm.com>
Date: Mon, 09 Jun 2025 16:21:32 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Rob Herring <robh@...nel.org>, Jeff Johnson <jjohnson@...nel.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, mhi@...ts.linux.dev,
        linux-wireless@...r.kernel.org, ath11k@...ts.infradead.org,
        qiang.yu@....qualcomm.com, quic_vbadigan@...cinc.com,
        quic_vpernami@...cinc.com, quic_mrana@...cinc.com,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
        Jeff Johnson <jeff.johnson@....qualcomm.com>,
        Miaoqing Pan <quic_miaoqing@...cinc.com>
Subject: [PATCH v4 11/11] wifi: ath11k: Add support for MHI bandwidth
 scaling

From: Miaoqing Pan <quic_miaoqing@...cinc.com>

Add support for MHI bandwidth scaling, which will reduce power consumption
if WLAN operates with lower bandwidth. This feature is only enabled for
QCA6390.

Bandwidth scaling is initiated by the endpoint firmware based upon the
bandwidth requirements, if there is high bandwidth data endpoint requests
for higher data rates or if there is less bandwidth they request for lower
data rates to reduce power. Endpoint initiates this through MHI protocol.

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04546-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1

Signed-off-by: Miaoqing Pan <quic_miaoqing@...cinc.com>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
 drivers/net/wireless/ath/ath11k/mhi.c | 41 +++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
index acd76e9392d31192aca6776319ef0829a1c69628..f79507c7a82244f9e9d8a3ae6765df3f9432ae8c 100644
--- a/drivers/net/wireless/ath/ath11k/mhi.c
+++ b/drivers/net/wireless/ath/ath11k/mhi.c
@@ -20,6 +20,7 @@
 #define MHI_TIMEOUT_DEFAULT_MS	20000
 #define RDDM_DUMP_SIZE	0x420000
 #define MHI_CB_INVALID	0xff
+#define MHI_BW_SCALE_CHAN_DB 126
 
 static const struct mhi_channel_config ath11k_mhi_channels_qca6390[] = {
 	{
@@ -73,6 +74,17 @@ static struct mhi_event_config ath11k_mhi_events_qca6390[] = {
 		.client_managed = false,
 		.offload_channel = false,
 	},
+	{
+		.num_elements = 8,
+		.irq_moderation_ms = 0,
+		.irq = 1,
+		.mode = MHI_DB_BRST_DISABLE,
+		.data_type = MHI_ER_BW_SCALE,
+		.priority = 2,
+		.hardware_event = false,
+		.client_managed = false,
+		.offload_channel = false,
+	},
 };
 
 static const struct mhi_controller_config ath11k_mhi_config_qca6390 = {
@@ -313,6 +325,33 @@ static void ath11k_mhi_op_write_reg(struct mhi_controller *mhi_cntrl,
 	writel(val, addr);
 }
 
+static int ath11k_mhi_op_get_misc_doorbell(struct mhi_controller *mhi_cntrl,
+					   enum mhi_er_data_type type)
+{
+	if (type == MHI_ER_BW_SCALE)
+		return MHI_BW_SCALE_CHAN_DB;
+
+	return -EINVAL;
+}
+
+static int ath11k_mhi_op_bw_scale(struct mhi_controller *mhi_cntrl,
+				  struct mhi_link_info *link_info)
+{
+	enum pci_bus_speed speed = pci_lnkctl2_bus_speed(link_info->target_link_speed);
+	struct ath11k_base *ab = dev_get_drvdata(mhi_cntrl->cntrl_dev);
+	struct pci_dev *pci_dev = to_pci_dev(ab->dev);
+	struct pci_dev *pdev;
+
+	if (!pci_dev)
+		return -EINVAL;
+
+	pdev = pci_upstream_bridge(pci_dev);
+	if (!pdev)
+		return -ENODEV;
+
+	return pcie_set_target_speed(pdev, speed, true);
+}
+
 static int ath11k_mhi_read_addr_from_dt(struct mhi_controller *mhi_ctrl)
 {
 	struct device_node *np;
@@ -389,6 +428,8 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
 	mhi_ctrl->status_cb = ath11k_mhi_op_status_cb;
 	mhi_ctrl->read_reg = ath11k_mhi_op_read_reg;
 	mhi_ctrl->write_reg = ath11k_mhi_op_write_reg;
+	mhi_ctrl->bw_scale = ath11k_mhi_op_bw_scale;
+	mhi_ctrl->get_misc_doorbell = ath11k_mhi_op_get_misc_doorbell;
 
 	switch (ab->hw_rev) {
 	case ATH11K_HW_QCN9074_HW10:

-- 
2.34.1