T9XX is the PCIe host device driver for MediaTek's
t900 modem. The driver uses the WWAN framework
infrastructure to create the following control ports
and network interfaces for data transactions.
* /dev/wwan0at0 - Interface that supports AT commands.
* /dev/wwan0mbim0 - Interface conforming to the MBIM
protocol.
* wwan0-X - Primary network interface for IP traffic.
The main blocks in the T9XX driver are:
* HW layer - Abstracts the hardware bus operations for
the device, and provides generic interfaces for the
transaction layer to get the device's information and
control the device's behavior. It includes:
* PCIe - Implements probe, removal and interrupt
handling.
* MHCCIF (Modem Host Cross-Core Interface) - Provides
interrupt channels for bidirectional event
notification such as handshake and port enumeration.
* Transaction layer - Implements data transactions for
the control plane and the data plane. It includes:
* DPMAIF (Data Plane Modem AP Interface) - Controls
the hardware that provides uplink and downlink
queues for the data path. The data exchange takes
place using circular buffers to share data buffer
addresses and metadata to describe the packets.
* CLDMA (Cross Layer DMA) - Manages the hardware
used by the port layer to send control messages to
the device using MediaTek's CCCI (Cross-Core
Communication Interface) protocol.
* TX Services - Dispatch packets from the port layer
to the device.
* RX Services - Dispatch packets to the port layer
when receiving packets from the device.
* Port layer - Provides control plane and data plane
interfaces to userspace. It includes:
* Control Plane - Provides device node interfaces
for controlling data transactions.
* Data Plane - Provides network link interfaces
wwanX (0, 1, 2...) for IP data transactions.
* Core logic - Contains the core logic to keep the
device working. It includes:
* FSM (Finite State Machine) - Monitors the state
of the device, and notifies each module when the
state changes.
The compilation of the T9XX driver is enabled by the
CONFIG_MTK_T9XX and CONFIG_MTK_T9XX_PCI config option
which depends on CONFIG_WWAN.
This v2 submission covers the control plane only
(patches 1-6). The data plane will follow in a
separate series once the control plane is accepted.
---
Changes in v2:
- Split series into control plane (this v2) and data plane (follow-up)
- Patch 1 (Add PCIe core):
- Rename BAR_NUM to MTK_PCI_BAR_NUM for driver prefix consistency
- Replace magic numbers in mtk_pci_setup_atr() with named defines
- Remove redundant ATR register comments, use blank line separators
- Add kernel-doc comments to all non-static functions
- Convert 4 MMIO wrapper functions to static inline in header [sashiko]
- Remove unnecessary unlikely() from IRQ validation paths
- Add irq_cnt == 0 and irq_id < 0 guards in mtk_pci_get_virq_id() [sashiko]
- Initialize hw_bits at declaration for consistency
- Merge same-type variable declarations into single lines
- Add #else/#endif comments for CONFIG_ACPI blocks
- Add newlines in mtk_pci_pldr() for readability
- Move return into default case in mtk_pci_dev_reset()
- Simplify mtk_mhccif_init() error path to use direct returns
- Change -EFAULT to -ENOLINK for PCIe link check failure
- Rename goto label "out" to "log_err" in mtk_pci_probe()
- Wrap long lines to stay within 80 columns
- Fix IRQ vector leak: add pci_free_irq_vectors() on error path [sashiko]
- Fix mtk_pci_remove() ordering: free IRQ before cancel_work_sync [sashiko]
- Fix mtk_pci_pldr() ACPI buffer leak: free first result before second call [sashiko]
- Replace msleep(500) with MTK_PLDR_POWER_OFF_DELAY_MS define
- Remove unused EXT_EVT_H2D_DRM_DISABLE_AP and related register define [sashiko]
- Increase MTK_IRQ_NAME_LEN from 20 to 32 to fix W=1 format-truncation warning [sashiko]
- Patch 2 (Add control plane transaction layer):
- Add kernel-doc comments to mtk_ctrl_init() and mtk_ctrl_exit()
- Change mtk_ctrl_exit() return type from int to void
- Set mdev->ctrl_blk to NULL after freeing in mtk_ctrl_exit() [sashiko]
- Change ctrl_blk from void* to typed struct mtk_ctrl_blk* [sashiko]
- Remove redundant "depends on MTK_T9XX" from MTK_T9XX_PCI Kconfig [sashiko]
- Use mtk_dev_free() instead of devm_kfree() in mtk_pci_probe() error path [sashiko]
- Patch 3 (Add control DMA interface):
- Add @ops kernel-doc parameter for mtk_ctrl_init()
- Rename 'err' to 'ret' consistently throughout the patch
- Reorder variable declarations to follow reverse Christmas tree style
- Change mtk_cldma_txq_free() return type from int to void
- Change mtk_cldma_rxq_free() return type from int to void
- Change mtk_cldma_exit() return type from int to void
- Remove unnecessary zero-initialization of ret in mtk_cldma_start_xfer()
- Remove unnecessary zero-initialization of ret in mtk_cldma_tx()
- Use direct return instead of goto out in mtk_cldma_submit_tx() error paths
- Move software state before HWO flag in mtk_cldma_submit_tx()
- Squash variable declarations in mtk_cldma_check_intr_status()
- Remove unlikely() from validation paths in mtk_cldma_check_ch_cfg()
- Clamp data_recv_len with min_t to prevent skb_over_panic in mtk_cldma_rx_skb_adjust() [sashiko]
- Use READ_ONCE() for HWO flag polling in mtk_cldma_check_rx_req() [sashiko]
- Fix mtk_cldma_rx_done_work() to always unmask interrupt on error path [sashiko]
- Add DMA address guard in mtk_cldma_txq_free() teardown loop [sashiko]
- Add IS_ERR() check for kthread_run() in mtk_ctrl_trb_srv_init() [sashiko]
- Fix queue_info memory leak on validation failure in mtk_pcie_hif_init() [sashiko]
- Handle non-EAGAIN errors in mtk_ctrl_trb_handler() TX path [sashiko]
- Fix 'err' typo to 'ret' in mtk_cldma_txbuf_set() error message
- Remove unused variable mdev in mtk_cldma_rx_check_again() [sashiko]
- Remove unused variables trans and ctrl_blk in mtk_cldma_txq_free() and mtk_cldma_rxq_free() [sashiko]
- Patch 4 (Add control port):
- Add @cfg kernel-doc parameter for mtk_ctrl_init()
- Update mtk_ctrl_init() return description to cover additional error codes
- Fix double list_del in mtk_port_stale_list_grp_cleanup() [sashiko]
- Fix direct mtk_port_trb_free() call to use kref_put() in mtk_port_ch_enable() error path [sashiko]
- Fix direct mtk_port_trb_free() call to use kref_put() in mtk_port_ch_disable() error path [sashiko]
- Add mtk_port_tbl_destroy() in mtk_port_mngr_init() error path to prevent port memory leak [sashiko]
- Change port_ops exit/reset/enable/disable callbacks from int to void
- Move -EIO dispatch comment to where the code was introduced
- Patch 5 (Add FSM thread):
- Add bounds check for rtft_entry in mtk_fsm_parse_hs2_msg() [sashiko]
- Add skb length validation before accessing ctrl_msg_header in mtk_fsm_sap_ctrl_msg_handler() [sashiko]
- Fix skb leak on CTRL_MSG_HS2 mismatch return in mtk_fsm_sap_ctrl_msg_handler() [sashiko]
- Add skb length validation before accessing ctrl_msg_header in mtk_fsm_md_ctrl_msg_handler() [sashiko]
- Replace devm_kzalloc/devm_kfree with kzalloc/kfree for FSM events [sashiko]
- Fix mtk_fsm_evt_submit() to return -ETIMEDOUT on blocking event timeout [sashiko]
- Change FSM kthread from TASK_INTERRUPTIBLE to TASK_UNINTERRUPTIBLE [sashiko]
- Remove unused variable hw_id in mtk_cldma_dev_exit() [sashiko]
- Patch 6 (Add AT & MBIM WWAN ports):
- Use imperative mode in commit message
- Remove unnecessary zero-initialization of ret in mtk_port_copy_data_from()
- Change copy_from_user() error code from -EFAULT to -EINVAL in mtk_port_copy_data_from()
- Return -EINVAL for zero-length write in mtk_port_common_write()
- Change mtk_port_wwan_exit/enable/disable() return type from int to void
- Fix packet_size to account for CCCI header reservation in mtk_port_common_write() [sashiko]
- Fix WWAN tx callbacks to consume skb and return 0 per wwan_port_ops contract [sashiko]
- Fix wwan_create_port() error path: clear ERR_PTR to NULL and call mtk_port_ch_disable() [sashiko]
- Patch 7 (Add maintainers entry): new patch
- Link to v1: https://patch.msgid.link/20260529-t9xx_driver_v1-v1-0-bdbfe2c01e57@compal.com
---
Jack Wu (7):
net: wwan: t9xx: Add PCIe core
net: wwan: t9xx: Add control plane transaction layer
net: wwan: t9xx: Add control DMA interface
net: wwan: t9xx: Add control port
net: wwan: t9xx: Add FSM thread
net: wwan: t9xx: Add AT & MBIM WWAN ports
net: wwan: t9xx: Add maintainers entry
MAINTAINERS | 9 +
drivers/net/wwan/Kconfig | 17 +
drivers/net/wwan/Makefile | 1 +
drivers/net/wwan/t9xx/Makefile | 14 +
drivers/net/wwan/t9xx/mtk_ctrl_plane.c | 111 ++
drivers/net/wwan/t9xx/mtk_ctrl_plane.h | 88 ++
drivers/net/wwan/t9xx/mtk_dev.c | 55 +
drivers/net/wwan/t9xx/mtk_dev.h | 114 ++
drivers/net/wwan/t9xx/mtk_fsm.c | 948 +++++++++++++++
drivers/net/wwan/t9xx/mtk_fsm.h | 140 +++
drivers/net/wwan/t9xx/mtk_port.c | 968 ++++++++++++++++
drivers/net/wwan/t9xx/mtk_port.h | 176 +++
drivers/net/wwan/t9xx/mtk_port_io.c | 573 +++++++++
drivers/net/wwan/t9xx/mtk_port_io.h | 41 +
drivers/net/wwan/t9xx/mtk_utility.h | 33 +
drivers/net/wwan/t9xx/pcie/Makefile | 15 +
drivers/net/wwan/t9xx/pcie/mtk_cldma.c | 1411 +++++++++++++++++++++++
drivers/net/wwan/t9xx/pcie/mtk_cldma.h | 173 +++
drivers/net/wwan/t9xx/pcie/mtk_cldma_drv.c | 371 ++++++
drivers/net/wwan/t9xx/pcie/mtk_cldma_drv.h | 174 +++
drivers/net/wwan/t9xx/pcie/mtk_cldma_drv_m9xx.c | 177 +++
drivers/net/wwan/t9xx/pcie/mtk_cldma_drv_m9xx.h | 101 ++
drivers/net/wwan/t9xx/pcie/mtk_ctrl_cfg_m9xx.c | 55 +
drivers/net/wwan/t9xx/pcie/mtk_pci.c | 1114 ++++++++++++++++++
drivers/net/wwan/t9xx/pcie/mtk_pci.h | 232 ++++
drivers/net/wwan/t9xx/pcie/mtk_pci_drv_m9xx.c | 69 ++
drivers/net/wwan/t9xx/pcie/mtk_pci_reg.h | 71 ++
drivers/net/wwan/t9xx/pcie/mtk_trans_ctrl.c | 603 ++++++++++
drivers/net/wwan/t9xx/pcie/mtk_trans_ctrl.h | 105 ++
29 files changed, 7959 insertions(+)
---
base-commit: eb3f4b7426cfd2b79d65b7d37155480b32259a11
change-id: 20260529-t9xx_driver_v1-1744f8af7739
Best regards,
--
Jack Wu <jackbb_wu@compal.com>