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Subject[RESEND PATCHv5 00/11] modem_shm: Driver for ST-E Thor M7400 LTE modem
Date
This patch-set implements a shared memory interface for ST-Ericsson modem
M7400. Review comments and feedback are welcome.

Patches are available at: git://github.com/sjurbren/modem-ipc.git for-next.


Introduction:
~~~~~~~~~~~~~
This patch-set introduces the Shared Memory Driver for ST-Ericsson's
Thor M7400 LTE modem.
The shared memory model is implemented for Chip-to-chip and
uses a reserved memory area and a number of bi-directional
channels. Each channel has it's own designated data area where payload
data is copied into.
Two different channel types are defined, one stream channel which is
implemented as a traditional ring-buffer, and a packet channel which
is a ring-buffer of fix sized buffers where each buffer contains
an array of CAIF frames.

The notification of read and write index updates are handled in a
separate driver called c2c_genio. This driver will be contributed separately,
but the API is included in this patch-set.

The channel configuration is stored in shared memory, each channel
has a designated area in shared memory for configuration data,
read and write indexes and a data area.

Configuration
~~~~~~~~~~~~~~~
IPC-TOC
+--------------------+ Index Area
| Channel Descr 0 | -----> +------------+
| | -+ | Read Index |
|--------------------| | |------------|
| Channel Descr 1 | | | Write Index|
| | | +------------+
|--------------------| | Data Area
| ... | | +------------+
| | +---> | |
+--------------------+ | |
| |
+------------+
A IPC-TOC (table of content) is used for holding configuration data
for the channels (struct shm_ipctoc). It contains an array of
channel descriptors (struct shm_ipctoc_channel). The channel
descriptors points out the data area and the location of
read and write indexes.

The configuration is provided from user-space using gen-netlink.
The gen-netlink format is defined in modem_shm_netlink.h and and handled
in shm_boot.c

Packet data
~~~~~~~~~~~
The packet channel is set up to minimize interrupts needed to
transfer a packet and to allow efficient DMA operations on the modem.
Ring Buffer Indexes:
+------------+
+-| Read Index |
| |------------|
| | Write Index|------------------------+
| +------------+ |
| |
V |
Buffer-0: V Buffer-1:
+----------------------------------------+---------------+---
|ofs,len|ofs,len| ....| frm-0|frm-1| ... | ofs,len | ....|...
+----------------------------------------+---------------+--
| | ^ ^
+---------------------+ |
+---------------------+
Packet data is organized in a channel containing a number of fixed-
size buffers. The channel has a read and write pointer to a buffer in a normal
ring-buffer fashion.

Each buffer holds an array of CAIF-frames, and starts with an descriptor array
containing pointers to the data frames in the buffer. The descriptor array
contains offset and length of each frame.

The packet device (caif_shm.c) is implemented as a network interface of
type ARPHRD_CAIF.

Stream data
~~~~~~~~~~~
The driver for the stream channel is implemented as a character device
interface to user space. The character device implements non-blocking open
and non-blocking IO in general. The character device is implementing
a traditional circular buffer directly in the shared memory region for
the channel.

Driver model
~~~~~~~~~~~~~~
A SHM bus is implemented, the example below shows one device
of each type (stream and packet):
/sys/bus/modem_shm
|-- devices
| |-- shm0 -> ../../../devices/modem_shm/shm0
| `-- shm1 -> ../../../devices/modem_shm/shm1
|-- drivers
| |-- caif_shm
| | |-- bind
| | |-- module -> ../../../../module/caif_shm
| | |-- uevent
| | |-- unbind
| | `-- shm1 -> ../../../../devices/shm/shm1
| `-- shm_chr
| |-- bind
| |-- module -> ../../../../module/shm_chr
| |-- uevent
| |-- unbind
| `-- shm0 -> ../../../../devices/shm/shm0
|-- drivers_autoprobe
|-- drivers_probe
`-- uevent


/sys/devices/modem_shm/
|-- bootimg
|-- caif_ready
|-- ipc_ready
|-- uevent
|-- shm0
| |-- driver -> ../../../bus/shm/drivers/modem_shm_chr
| |-- misc
| | `-- shm0
| | |-- dev
| | |-- device -> ../../../shm0
| | |-- subsystem -> ../../../../../class/misc
| | `-- uevent
| |-- subsystem -> ../../../bus/shm
| `-- uevent
`-- shm1
|-- driver -> ../../../bus/shm/drivers/caif_shm
|-- subsystem -> ../../../bus/shm
`-- uevent

Sjur Brændeland (11):
modem_shm: Shared Memory layout for ST-E M7400 driver.
modem_shm: Channel config definitions for ST-E M7400 driver.
modem_shm: Configuration for SHM Channel an devices.
modem_shm: geni/geno driver interface.
modem_shm: genio dummy driver
modem_shm: Add SHM device bus.
modem_shm: Add shm device implementation
modem_shm: SHM Configuration data handling
modem_shm: Character device for SHM channel access.
modem_shm: Makefile and Kconfig for M7400 Shared Memory Drivers
caif_shm: Add CAIF driver for Shared memory for M7400

drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/modem_shm/Kconfig | 62 ++
drivers/modem_shm/Makefile | 5 +
drivers/modem_shm/dummy_c2c_genio.c | 76 ++
drivers/modem_shm/shm_boot.c | 1208 ++++++++++++++++++++++++++
drivers/modem_shm/shm_bus.c | 113 +++
drivers/modem_shm/shm_chr.c | 1242 +++++++++++++++++++++++++++
drivers/modem_shm/shm_dev.c | 527 ++++++++++++
drivers/modem_shm/shm_ipctoc.h | 154 ++++
drivers/net/caif/Kconfig | 12 +-
drivers/net/caif/Makefile | 3 +-
drivers/net/caif/caif_shm.c | 900 +++++++++++++++++++
include/linux/Kbuild | 1 +
include/linux/c2c_genio.h | 195 +++++
include/linux/modem_shm/Kbuild | 1 +
include/linux/modem_shm/modem_shm_netlink.h | 95 ++
include/linux/modem_shm/shm_dev.h | 245 ++++++
18 files changed, 4840 insertions(+), 2 deletions(-)
create mode 100644 drivers/modem_shm/Kconfig
create mode 100644 drivers/modem_shm/Makefile
create mode 100644 drivers/modem_shm/dummy_c2c_genio.c
create mode 100644 drivers/modem_shm/shm_boot.c
create mode 100644 drivers/modem_shm/shm_bus.c
create mode 100644 drivers/modem_shm/shm_chr.c
create mode 100644 drivers/modem_shm/shm_dev.c
create mode 100644 drivers/modem_shm/shm_ipctoc.h
create mode 100644 drivers/net/caif/caif_shm.c
create mode 100644 include/linux/c2c_genio.h
create mode 100644 include/linux/modem_shm/Kbuild
create mode 100644 include/linux/modem_shm/modem_shm_netlink.h
create mode 100644 include/linux/modem_shm/shm_dev.h
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