Synopsys eDMA IP is normally distributed along with Synopsys PCIe
EndPoint IP (depends of the use and licensing agreement).
This IP requires some basic configurations, such as:
- eDMA registers BAR
- eDMA registers offset
- eDMA registers size
- eDMA linked list memory BAR
- eDMA linked list memory offset
- eDMA linked list memory size
- eDMA data memory BAR
- eDMA data memory offset
- eDMA data memory size
- eDMA version
- eDMA mode
- IRQs available for eDMA
As a working example, PCIe glue-logic will attach to a Synopsys PCIe
EndPoint IP prototype kit (Vendor ID = 0x16c3, Device ID = 0xedda),
which has built-in an eDMA IP with this default configuration:
- eDMA registers BAR = 0
- eDMA registers offset = 0x00001000 (4 Kbytes)
- eDMA registers size = 0x00002000 (8 Kbytes)
- eDMA linked list memory BAR = 2
- eDMA linked list memory offset = 0x00000000 (0 Kbytes)
- eDMA linked list memory size = 0x00800000 (8 Mbytes)
- eDMA data memory BAR = 2
- eDMA data memory offset = 0x00800000 (8 Mbytes)
- eDMA data memory size = 0x03800000 (56 Mbytes)
- eDMA version = 0
- eDMA mode = EDMA_MODE_UNROLL
- IRQs = 1
This driver can be compile as built-in or external module in kernel.
To enable this driver just select DW_EDMA_PCIE option in kernel
configuration, however it requires and selects automatically DW_EDMA
option too.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add support for the eDMA IP version 0 driver for both register maps (legacy
and unroll).
The legacy register mapping was the initial implementation, which consisted
in having all registers belonging to channels multiplexed, which could be
change anytime (which could led a race-condition) by view port register
(access to only one channel available each time).
This register mapping is not very effective and efficient in a multithread
environment, which has led to the development of unroll registers mapping,
which consists of having all channels registers accessible any time by
spreading all channels registers by an offset between them.
This version supports a maximum of 16 independent channels (8 write +
8 read), which can run simultaneously.
Implements a scatter-gather transfer through a linked list, where the size
of linked list depends on the allocated memory divided equally among all
channels.
Each linked list descriptor can transfer from 1 byte to 4 Gbytes and is
alignmented to DWORD.
Both SAR (Source Address Register) and DAR (Destination Address Register)
are alignmented to byte.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add Synopsys PCIe Endpoint eDMA IP core driver to kernel.
This IP is generally distributed with Synopsys PCIe Endpoint IP (depends
of the use and licensing agreement).
This core driver, initializes and configures the eDMA IP using vma-helpers
functions and dma-engine subsystem.
This driver can be compile as built-in or external module in kernel.
To enable this driver just select DW_EDMA option in kernel configuration,
however it requires and selects automatically DMA_ENGINE and
DMA_VIRTUAL_CHANNELS option too.
In order to transfer data from point A to B as fast as possible this IP
requires a dedicated memory space containing linked list of elements.
All elements of this linked list are continuous and each one describes a
data transfer (source and destination addresses, length and a control
variable).
For the sake of simplicity, lets assume a memory space for channel write
0 which allows about 42 elements.
+---------+
| Desc #0 |-+
+---------+ |
V
+----------+
| Chunk #0 |-+
| CB = 1 | | +----------+ +-----+ +-----------+ +-----+
+----------+ +->| Burst #0 |->| ... |->| Burst #41 |->| llp |
| +----------+ +-----+ +-----------+ +-----+
V
+----------+
| Chunk #1 |-+
| CB = 0 | | +-----------+ +-----+ +-----------+ +-----+
+----------+ +->| Burst #42 |->| ... |->| Burst #83 |->| llp |
| +-----------+ +-----+ +-----------+ +-----+
V
+----------+
| Chunk #2 |-+
| CB = 1 | | +-----------+ +-----+ +------------+ +-----+
+----------+ +->| Burst #84 |->| ... |->| Burst #125 |->| llp |
| +-----------+ +-----+ +------------+ +-----+
V
+----------+
| Chunk #3 |-+
| CB = 0 | | +------------+ +-----+ +------------+ +-----+
+----------+ +->| Burst #126 |->| ... |->| Burst #129 |->| llp |
+------------+ +-----+ +------------+ +-----+
Legend:
- Linked list, also know as Chunk
- Linked list element*, also know as Burst *CB*, also know as Change Bit,
it's a control bit (and typically is toggled) that allows to easily
identify and differentiate between the current linked list and the
previous or the next one.
- LLP, is a special element that indicates the end of the linked list
element stream also informs that the next CB should be toggle
On every last Burst of the Chunk (Burst #41, Burst #83, Burst #125 or
even Burst #129) is set some flags on their control variable (RIE and
LIE bits) that will trigger the send of "done" interruption.
On the interruptions callback, is decided whether to recycle the linked
list memory space by writing a new set of Bursts elements (if still
exists Chunks to transfer) or is considered completed (if there is no
Chunks available to transfer).
On scatter-gather transfer mode, the client will submit a scatter-gather
list of n (on this case 130) elements, that will be divide in multiple
Chunks, each Chunk will have (on this case 42) a limited number of
Bursts and after transferring all Bursts, an interrupt will be
triggered, which will allow to recycle the all linked list dedicated
memory again with the new information relative to the next Chunk and
respective Burst associated and repeat the whole cycle again.
On cyclic transfer mode, the client will submit a buffer pointer, length
of it and number of repetitions, in this case each burst will correspond
directly to each repetition.
Each Burst can describes a data transfer from point A(source) to point
B(destination) with a length that can be from 1 byte up to 4 GB. Since
dedicated the memory space where the linked list will reside is limited,
the whole n burst elements will be organized in several Chunks, that
will be used later to recycle the dedicated memory space to initiate a
new sequence of data transfers.
The whole transfer is considered has completed when it was transferred
all bursts.
Currently this IP has a set well-known register map, which includes
support for legacy and unroll modes. Legacy mode is version of this
register map that has multiplexer register that allows to switch
registers between all write and read channels and the unroll modes
repeats all write and read channels registers with an offset between
them. This register map is called v0.
The IP team is creating a new register map more suitable to the latest
PCIe features, that very likely will change the map register, which this
version will be called v1. As soon as this new version is released by
the IP team the support for this version in be included on this driver.
According to the logic, patches 1, 2 and 3 should be squashed into 1
unique patch, but for the sake of simplicity of review, it was divided
in this 3 patches files.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Gustavo Pimentel