[PATCH 03/18] wifi: mt76: mt7925: add MT7927 CBTOP remap and chip initialization
Javier Tia
floss at jetm.me
Fri Mar 6 16:33:22 PST 2026
The MT7927 combo chip has an additional bus fabric called CBInfra
(ConnectaBus Infrastructure) between PCIe and the WiFi subsystem.
Without configuring the CBTOP address remap, all MMIO reads to WiFi
registers return zero.
Add mt7927_cbtop_remap() to configure the PCIe address mapping for WiFi
and Bluetooth subsystems, and mt7927_chip_init() to perform the CBInfra
initialization sequence:
1. EMI sleep protect enable
2. WF subsystem reset via CBInfra RGU
3. MCU ownership acquisition
4. Poll ROMCODE_INDEX for MCU idle (0x1D1E)
5. MCIF remap for host DMA
6. PCIe sleep disable
Skip the early CLR_OWN in probe for MT7927 since CBTOP remap is not yet
configured at that point - the ROM's WFDMA init would fail.
Register values derived from Loong0x00's reverse-engineered MT7927
driver.
Tested-by: Marcin FM <marcin at lgic.pl>
Tested-by: Cristian-Florin Radoi <radoi.chris at gmail.com>
Tested-by: George Salukvadze <giosal90 at gmail.com>
Tested-by: Evgeny Kapusta <3193631 at gmail.com>
Tested-by: Samu Toljamo <samu.toljamo at gmail.com>
Tested-by: Ariel Rosenfeld <ariel.rosenfeld.750 at gmail.com>
Tested-by: Chapuis Dario <chapuisdario4 at gmail.com>
Tested-by: Thibaut François <tibo at humeurlibre.fr>
Tested-by: 张旭涵 <Loong.0x00 at gmail.com>
Signed-off-by: Javier Tia <floss at jetm.me>
---
drivers/net/wireless/mediatek/mt76/mt7925/pci.c | 90 ++++++++++++++++++++++--
drivers/net/wireless/mediatek/mt76/mt792x_regs.h | 18 +++++
2 files changed, 101 insertions(+), 7 deletions(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
index 54eac5c6e509..c16ec05c5601 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
@@ -270,6 +270,60 @@ static int mt7925_dma_init(struct mt792x_dev *dev)
return mt792x_dma_enable(dev);
}
+static int mt7927_chip_init(struct mt792x_dev *dev)
+{
+ struct mt76_dev *mdev = &dev->mt76;
+ u32 val;
+
+ /* EMI sleep protect */
+ mt76_rmw_field(dev, MT_HW_EMI_CTL, MT_HW_EMI_CTL_SLPPROT_EN, 1);
+
+ /* WF subsystem reset via CBInfra RGU */
+ mt76_set(dev, MT_CBINFRA_RGU_WF_RST, MT_CBINFRA_RGU_WF_RST_WF_SUBSYS);
+ msleep(1);
+ mt76_clear(dev, MT_CBINFRA_RGU_WF_RST,
+ MT_CBINFRA_RGU_WF_RST_WF_SUBSYS);
+ msleep(5);
+
+ /* MCU ownership */
+ mt76_wr(dev, MT_CBINFRA_MCU_OWN_SET, BIT(0));
+
+ /* Poll ROMCODE_INDEX for MCU idle */
+ if (!__mt76_poll_msec(mdev, MT_ROMCODE_INDEX,
+ 0xffff, MT_MCU_IDLE_VALUE, 2000)) {
+ val = mt76_rr(dev, MT_ROMCODE_INDEX);
+ dev_err(mdev->dev,
+ "MT7927 MCU idle timeout (ROMCODE_INDEX=0x%04x)\n",
+ val & 0xffff);
+ return -ETIMEDOUT;
+ }
+
+ /* MCIF remap - MCU needs this to DMA to host memory */
+ mt76_wr(dev, MT_MCIF_REMAP_WF_1_BA, MT_MCIF_REMAP_WF_1_BA_VAL);
+
+ /* Disable PCIe sleep */
+ mt76_wr(dev, MT_CBINFRA_SLP_CTRL, 0xffffffff);
+
+ /* Clear CONNINFRA wakeup */
+ mt76_wr(dev, MT_CBINFRA_WAKEPU_TOP, 0x0);
+
+ return 0;
+}
+
+static void mt7927_cbtop_remap(struct mt792x_dev *dev)
+{
+ /* CONNINFRA wakeup - required before CBInfra register access */
+ mt76_wr(dev, MT_CBINFRA_WAKEPU_TOP, 0x1);
+ usleep_range(1000, 2000);
+
+ /* Configure CBTOP PCIe address remap for WF and BT */
+ mt76_wr(dev, MT_CBINFRA_MISC0_REMAP_WF, MT_CBINFRA_REMAP_WF_VAL);
+ mt76_wr(dev, MT_CBINFRA_MISC0_REMAP_BT, MT_CBINFRA_REMAP_BT_VAL);
+
+ /* Readback to push writes */
+ mt76_rr(dev, MT_CBINFRA_MISC0_REMAP_WF);
+}
+
static int mt7925_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
@@ -314,6 +368,7 @@ static int mt7925_pci_probe(struct pci_dev *pdev,
struct mt76_bus_ops *bus_ops;
struct mt792x_dev *dev;
struct mt76_dev *mdev;
+ bool is_mt7927_hw;
u8 features;
int ret;
u16 cmd;
@@ -385,24 +440,45 @@ static int mt7925_pci_probe(struct pci_dev *pdev,
if (!mt7925_disable_aspm && mt76_pci_aspm_supported(pdev))
dev->aspm_supported = true;
+ is_mt7927_hw = (pdev->device == 0x6639 || pdev->device == 0x7927);
+
ret = __mt792x_mcu_fw_pmctrl(dev);
if (ret)
goto err_free_dev;
- ret = __mt792xe_mcu_drv_pmctrl(dev);
- if (ret)
- goto err_free_dev;
+ if (!is_mt7927_hw) {
+ ret = __mt792xe_mcu_drv_pmctrl(dev);
+ if (ret)
+ goto err_free_dev;
+ }
+
+ if (is_mt7927_hw)
+ mt7927_cbtop_remap(dev);
mdev->rev = (mt76_rr(dev, MT_HW_CHIPID) << 16) |
(mt76_rr(dev, MT_HW_REV) & 0xff);
dev_info(mdev->dev, "ASIC revision: %04x\n", mdev->rev);
- mt76_rmw_field(dev, MT_HW_EMI_CTL, MT_HW_EMI_CTL_SLPPROT_EN, 1);
+ /* Force chip ID for MT7927 hardware if CHIPID read returns garbage */
+ if (is_mt7927_hw && (mdev->rev >> 16) != 0x7927) {
+ dev_info(mdev->dev,
+ "MT7927 raw CHIPID=0x%04x, forcing chip=0x7927\n",
+ (u16)(mdev->rev >> 16));
+ mdev->rev = (0x7927 << 16) | (mdev->rev & 0xff);
+ }
- ret = mt792x_wfsys_reset(dev);
- if (ret)
- goto err_free_dev;
+ if (is_mt7927_hw) {
+ ret = mt7927_chip_init(dev);
+ if (ret)
+ goto err_free_dev;
+ } else {
+ mt76_rmw_field(dev, MT_HW_EMI_CTL,
+ MT_HW_EMI_CTL_SLPPROT_EN, 1);
+ ret = mt792x_wfsys_reset(dev);
+ if (ret)
+ goto err_free_dev;
+ }
mt76_wr(dev, irq_map.host_irq_enable, 0);
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
index acf627aed609..0f75dca0a96c 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
@@ -484,4 +484,22 @@
#define WFSYS_SW_RST_B BIT(0)
#define WFSYS_SW_INIT_DONE BIT(4)
+/* CBInfra registers - MT7927 combo chip */
+#define MT_CBINFRA_WAKEPU_TOP 0xe01a0
+#define MT_CBINFRA_MISC0_REMAP_WF 0x1f6554
+#define MT_CBINFRA_MISC0_REMAP_BT 0x1f6558
+#define MT_CBINFRA_RGU_WF_RST 0x1f8600
+#define MT_CBINFRA_RGU_WF_RST_WF_SUBSYS BIT(4)
+#define MT_CBINFRA_MCU_OWN_SET 0x1f5034
+#define MT_CBINFRA_SLP_CTRL 0x1f5018
+#define MT_ROMCODE_INDEX 0xc1604
+#define MT_MCU_IDLE_VALUE 0x1d1e
+#define MT_MCIF_REMAP_WF_1_BA 0xd1034
+
+/* CBInfra CBTOP remap values */
+#define MT_CBINFRA_REMAP_WF_VAL 0x74037001
+#define MT_CBINFRA_REMAP_BT_VAL 0x70007000
+
+#define MT_MCIF_REMAP_WF_1_BA_VAL 0x18051803
+
#endif /* __MT792X_REGS_H */
--
2.53.0
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