Qualcomm Kernel » History » Revision 7
Revision 6 (laforge, 12/16/2016 09:33 PM) → Revision 7/22 (laforge, 12/17/2016 11:17 AM)
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h1. Qualcomm Kernel
Random notes about the Qualcomm Kernel as used on the MDM9615
h2. diag
h3. diag forwarding
<pre>
drivers/char/diag/diagfwd.[ch]
drivers/usb/gadget/f_diag.[ch]
drivers/usb/misc/diag_bridge.c
</pre>
* the usb diag gadget handles diag packet read/write over usb
* issues events like USB_DIAG_READ_DONE
* picked up by diagfwd.c
** can forward diag requests via SMD shared memory to other processors
h3. diag char
The kernel exports a /dev/diag char device which userspce processes can
use to register/listen for DIAG events from the system, or actually
register a DIAG 'subsystem' themselves which can then be controlled from
QXDM.
<pre>
drivers/char/diag/diagchar_core.c
</pre>
* ioctl()s for diag configuration
* supports several concurrent diag clients
* diag logging can be directed to USB/HSIC, character device and more
** {USB,CALLBACK,MEMORY_DEVICE,UART,NO_LOGGING}_MODE
drivers/char/diag/diag_dci.c
* DCI table is a routing table where pid/sockets can register for a
given DCI. socket close/cleanup code releases all DCI routes for
that socket.
h4. DIAG_IOCTL_COMMAND_REG
* Register a new DIAG command so it can be used from the outside world (QXDM)
* use 'struct diag_cmd_reg_entry_t' per command
* driver keeps a driver->cmd_reg_list of registered commands
h4. DIAG_IOCTL_COMMAND_DEREG
* unregister debug command
h4. DIAG_IOCTL_GET_DELAYED_RSP_ID
h4. DIAG_IOCTL_DCI_REG
h4. DIAG_IOCTL_DCI_DEINIT
h4. DIAG_IOCTL_DCI_SUPPORT
h4. DIAG_IOCTL_DCI_HEALTH_STATS
h4. DIAG_IOCTL_DCI_LOG_STATUS
h4. DIAG_IOCTL_DCI_EVENT_STATUS
h4. DIAG_IOCTL_DCI_CLEAR_LOGS
h4. DIAG_IOCTL_DCI_CLEAR_EVENTS
h4. DIAG_IOCTL_LSM_DEINIT
h4. DIAG_IOCTL_SWITCH_LOGGING
* switch between USB and shared-memory diag
*
h4. DIAG_IOCTL_REMOTE_DEV
h4. DIAG_IOCTL_VOTE_REAL_TIME
h4. DIAG_IOCTL_GET_REAL_TIME
h4. DIAG_IOCTL_PERIPHERAL_BUF_CONFIG
h4. DIAG_IOCTL_PERIPHERAL_BUF_DRAIN
h4. DIAG_IOCTL_REGISTER_CALLBACK
* doen't really do anything but checking arguments ?!?
h4. DIAG_IOCTL_HDLC_TOGGLE
enable or disable HDLC framing of /dev/diag
h2. SMD (shared memory)
* SMD sub-systems:
** Modem (assumed to be hexagon with modem firmware?)
** Q6 (formerly known as LPASS == Low Power Audio SubSystem)
** DSPS
** WCNSS (Wireless Connectivity Sub System) aka 'riva'
** RPM (Resource Power Manager)
* inter-processor-interrupts for various 'edges'
h3. core driver
* arch/arm/mach-msm/smd.c
h4. api
* smd_open()
* smd_close()
* smd_write*()
* smd_read*()
* smsm_*()
h3. MSM IPC socket
* arch/arm/mach-msm/ipc_socket.c
* AF_MSM_IPC
h3. packet ports
* Some kind of packet oriented interface towards the SMD
* msm_smd_pkt.c contains driver
** smdpkt0..7+smd22 devices, 2048 byte buffer
** open/release/read/write/poll syscalls implemented
h2. smem_log
This is some kidn of high speed shared memory based event log to which all processors can log events.
Userspace applications can use write() to @/dev/smem_log@ to add log entries.
Qualcomm uses a proprietary minimal shim layer offering SMEM_LOG_EVENT and SMEM_LOG_EVENT6 macros
that can be used to write events with an event ID plus three data words or six data words, respectively.
The shared memory log can be read from linux userspace via debugfs, see the devices in @/sys/kernel/debug/smem_log@
and simply use @cat@ on them. You will get lines like
<pre>
MODM: 3982377401 000d0000: 00000001: 03000019 01000028 01000015 53505041 00000061 5f696d71
MODM: 3982378159 QCSI: 00000004: 00040029 00240015 00000003 00000001 0000002b 00000000
MODM: 3982378619 000d0000: 00000001: 03000019 0100002b 01000015 53505041 00000061 5f696d71
APPS: 3982397356 QCCI: 00000005: 0004001d 0024000e 00000003 00000003 00000019 00000000
APPS: 3982400571 QCCI: 00000005: 00040029 0024000e 00000003 00000003 00000019 00000000
MODM: 1841235211 QCSI: 00000004: 0004001e 0024001c 00000003 00000001 00000028 00000000
MODM: 1841236665 000d0000: 00000001: 03000019 01000028 0101001c 53505041 00000061 5f696d71
MODM: 1841241411 QCSI: 00000004: 0004002a 0024001c 00000003 00000001 0000002b 00000000
MODM: 1841242246 000d0000: 00000001: 03000019 0100002b 0100001c 53505041 00000061 5f696d71
MODM: 1841243796 QCSI: 00000004: 0004002b 00660019 00000003 00000001 0000002b 00000000
MODM: 1841244286 000d0000: 00000001: 03000019 0100002b 01000019 53505041 00000061 5f696d71
APPS: 1841255456 QCCI: 00000005: 0004001e 00240015 00000003 00000003 00000019 00000000
MODM: 1841255335 000d0000: 00000002: 0100ffff 0300ffff 07000014 53505041 0000016c 74646d73
MODM: 1841255828 000d0000: 00000702: 00000001 00000028 00000007
APPS: 1841261430 QCCI: 00000005: 0004002a 00240015 00000003 00000003 00000019 00000000
</pre>
