There are multiple issues with bcm2835_dma_abort() (which is called on
termination of a transaction):
* The algorithm to abort the transaction first pauses the channel by
clearing the ACTIVE flag in the CS register, then waits for the PAUSED
flag to clear. Page 49 of the spec documents the latter as follows:
"Indicates if the DMA is currently paused and not transferring data.
This will occur if the active bit has been cleared [...]"
https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
So the function is entering an infinite loop because it is waiting for
PAUSED to clear which is always set due to the function having cleared
the ACTIVE flag. The only thing that's saving it from itself is the
upper bound of 10000 loop iterations.
The code comment says that the intention is to "wait for any current
AXI transfer to complete", so the author probably wanted to check the
WAITING_FOR_OUTSTANDING_WRITES flag instead. Amend the function
accordingly.
* The CS register is only read at the beginning of the function. It
needs to be read again after pausing the channel and before checking
for outstanding writes, otherwise writes which were issued between
the register read at the beginning of the function and pausing the
channel may not be waited for.
* The function seeks to abort the transfer by writing 0 to the NEXTCONBK
register and setting the ABORT and ACTIVE flags. Thereby, the 0 in
NEXTCONBK is sought to be loaded into the CONBLK_AD register. However
experimentation has shown this approach to not work: The CONBLK_AD
register remains the same as before and the CS register contains
0x00000030 (PAUSED | DREQ_STOPS_DMA). In other words, the control
block is not aborted but merely paused and it will be resumed once the
next DMA transaction is started. That is absolutely not the desired
behavior.
A simpler approach is to set the channel's RESET flag instead. This
reliably zeroes the NEXTCONBK as well as the CS register. It requires
less code and only a single MMIO write. This is also what popular
user space DMA drivers do, e.g.:
https://github.com/metachris/RPIO/blob/master/source/c_pwm/pwm.c
Note that the spec is contradictory whether the NEXTCONBK register
is writeable at all. On the one hand, page 41 claims:
"The value loaded into the NEXTCONBK register can be overwritten so
that the linked list of Control Block data structures can be
dynamically altered. However it is only safe to do this when the DMA
is paused."
On the other hand, page 40 specifies:
"Only three registers in each channel's register set are directly
writeable (CS, CONBLK_AD and DEBUG). The other registers (TI,
SOURCE_AD, DEST_AD, TXFR_LEN, STRIDE & NEXTCONBK), are automatically
loaded from a Control Block data structure held in external memory."
Fixes: 96286b5766 ("dmaengine: Add support for BCM2835")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v3.14+
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Meier <florian.meier@koalo.de>
Cc: Clive Messer <clive.m.messer@gmail.com>
Cc: Matthias Reichl <hias@horus.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Kauer <florian.kauer@koalo.de>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
If IRQ handlers are threaded (either because CONFIG_PREEMPT_RT_BASE is
enabled or "threadirqs" was passed on the command line) and if system
load is sufficiently high that wakeup latency of IRQ threads degrades,
SPI DMA transactions on the BCM2835 occasionally break like this:
ks8851 spi0.0: SPI transfer timed out
bcm2835-dma 3f007000.dma: DMA transfer could not be terminated
ks8851 spi0.0 eth2: ks8851_rdfifo: spi_sync() failed
The root cause is an assumption made by the DMA driver which is
documented in a code comment in bcm2835_dma_terminate_all():
/*
* Stop DMA activity: we assume the callback will not be called
* after bcm_dma_abort() returns (even if it does, it will see
* c->desc is NULL and exit.)
*/
That assumption falls apart if the IRQ handler bcm2835_dma_callback() is
threaded: A client may terminate a descriptor and issue a new one
before the IRQ handler had a chance to run. In fact the IRQ handler may
miss an *arbitrary* number of descriptors. The result is the following
race condition:
1. A descriptor finishes, its interrupt is deferred to the IRQ thread.
2. A client calls dma_terminate_async() which sets channel->desc = NULL.
3. The client issues a new descriptor. Because channel->desc is NULL,
bcm2835_dma_issue_pending() immediately starts the descriptor.
4. Finally the IRQ thread runs and writes BCM2835_DMA_INT to the CS
register to acknowledge the interrupt. This clears the ACTIVE flag,
so the newly issued descriptor is paused in the middle of the
transaction. Because channel->desc is not NULL, the IRQ thread
finalizes the descriptor and tries to start the next one.
I see two possible solutions: The first is to call synchronize_irq()
in bcm2835_dma_issue_pending() to wait until the IRQ thread has
finished before issuing a new descriptor. The downside of this approach
is unnecessary latency if clients desire rapidly terminating and
re-issuing descriptors and don't have any use for an IRQ callback.
(The SPI TX DMA channel is a case in point.)
A better alternative is to make the IRQ thread recognize that it has
missed descriptors and avoid finalizing the newly issued descriptor.
So first of all, set the ACTIVE flag when acknowledging the interrupt.
This keeps a newly issued descriptor running.
If the descriptor was finished, the channel remains idle despite the
ACTIVE flag being set. However the ACTIVE flag can then no longer be
used to check whether the channel is idle, so instead check whether
the register containing the current control block address is zero
and finalize the current descriptor only if so.
That way, there is no impact on latency and throughput if the client
doesn't care for the interrupt: Only minimal additional overhead is
introduced for non-cyclic descriptors as one further MMIO read is
necessary per interrupt to check for idleness of the channel. Cyclic
descriptors are sped up slightly by removing one MMIO write per
interrupt.
Fixes: 96286b5766 ("dmaengine: Add support for BCM2835")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v3.14+
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Meier <florian.meier@koalo.de>
Cc: Clive Messer <clive.m.messer@gmail.com>
Cc: Matthias Reichl <hias@horus.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Kauer <florian.kauer@koalo.de>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Once the "ld_queue" list is not empty, next descriptor will migrate
into "ld_active" list. The "desc" variable will be overwritten
during that transition. And later the dmaengine_desc_get_callback_invoke()
will use it as an argument. As result we invoke wrong callback.
That behaviour was in place since:
commit fcaaba6c71 ("dmaengine: imx-dma: fix callback path in tasklet").
But after commit 4cd13c21b2 ("softirq: Let ksoftirqd do its job")
things got worse, since possible delay between tasklet_schedule()
from DMA irq handler and actual tasklet function execution got bigger.
And that gave more time for new DMA request to be submitted and
to be put into "ld_queue" list.
It has been noticed that DMA issue is causing problems for "mxc-mmc"
driver. While stressing the system with heavy network traffic and
writing/reading to/from sd card simultaneously the timeout may happen:
10013000.sdhci: mxcmci_watchdog: read time out (status = 0x30004900)
That often lead to file system corruption.
Signed-off-by: Leonid Iziumtsev <leonid.iziumtsev@gmail.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Cc: stable@vger.kernel.org
This mapping needs to be created in order for slave dma transfers
to work on systems with SMMU. The implementation mostly mimics the
one in pl330 dma driver, authored by Robin Murphy.
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
atchan->status variable is used to store two different information:
- pass channel interrupts status from interrupt handler to tasklet;
- channel information like whether it is cyclic or paused;
This causes a bug when device_terminate_all() is called,
(AT_XDMAC_CHAN_IS_CYCLIC cleared on atchan->status) and then a late End
of Block interrupt arrives (AT_XDMAC_CIS_BIS), which sets bit 0 of
atchan->status. Bit 0 is also used for AT_XDMAC_CHAN_IS_CYCLIC, so when
a new descriptor for a cyclic transfer is created, the driver reports
the channel as in use:
if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
dev_err(chan2dev(chan), "channel currently used\n");
return NULL;
}
This patch fixes the bug by adding a different struct member to keep
the interrupts status separated from the channel status bits.
Fixes: e1f7c9eee7 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit fixes the issue that USB-DMAC hangs silently after system
resumes on R-Car Gen3 hence renesas_usbhs will not work correctly
when using USB-DMAC for bulk transfer e.g. ethernet or serial
gadgets.
The issue can be reproduced by these steps:
1. modprobe g_serial
2. Suspend and resume system.
3. connect a usb cable to host side
4. Transfer data from Host to Target
5. cat /dev/ttyGS0 (Target side)
6. echo "test" > /dev/ttyACM0 (Host side)
The 'cat' will not result anything. However, system still can work
normally.
Currently, USB-DMAC driver does not have system sleep callbacks hence
this driver relies on the PM core to force runtime suspend/resume to
suspend and reinitialize USB-DMAC during system resume. After
the commit 17218e0092 ("PM / genpd: Stop/start devices without
pm_runtime_force_suspend/resume()"), PM core will not force
runtime suspend/resume anymore so this issue happens.
To solve this, make system suspend resume explicit by using
pm_runtime_force_{suspend,resume}() as the system sleep callbacks.
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() is used to make sure USB-DMAC
suspended after and initialized before renesas_usbhs."
Signed-off-by: Phuong Nguyen <phuong.nguyen.xw@renesas.com>
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Cc: <stable@vger.kernel.org> # v4.16+
[shimoda: revise the commit log and add Cc tag]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Pass ->dev to dma_alloc_coherent() API. We need this
because dma_alloc_coherent() makes use of dev parameter
and receiving NULL will result in a crash.
Signed-off-by: Andy Duan <fugang.duan@nxp.com>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The warning got introduced by commit 930507c183 ("arm64: add basic
Kconfig symbols for i.MX8"). Since it got enabled for arm64. The warning
haven't been seen before since size_t was 'unsigned int' when built on
arm32.
../drivers/dma/imx-dma.c: In function ‘imxdma_sg_next’:
../include/linux/kernel.h:846:29: warning: comparison of distinct pointer types lacks a cast
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
^~
../include/linux/kernel.h:860:4: note: in expansion of macro ‘__typecheck’
(__typecheck(x, y) && __no_side_effects(x, y))
^~~~~~~~~~~
../include/linux/kernel.h:870:24: note: in expansion of macro ‘__safe_cmp’
__builtin_choose_expr(__safe_cmp(x, y), \
^~~~~~~~~~
../include/linux/kernel.h:879:19: note: in expansion of macro ‘__careful_cmp’
#define min(x, y) __careful_cmp(x, y, <)
^~~~~~~~~~~~~
../drivers/dma/imx-dma.c:288:8: note: in expansion of macro ‘min’
now = min(d->len, sg_dma_len(sg));
^~~
Rework so that we use min_t and pass in the size_t that returns the
minimum of two values, using the specified type.
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/dma/xilinx/xilinx_dma.c: In function 'xilinx_vdma_start_transfer':
drivers/dma/xilinx/xilinx_dma.c:1104:33: warning:
variable 'tail_segment' set but not used [-Wunused-but-set-variable]
It not used since commit b8349172b4 ("dmaengine: xilinx_dma: Drop SG support
for VDMA IP")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
When dma_cookie_complete() is called in hidma_process_completed(),
dma_cookie_status() will return DMA_COMPLETE in hidma_tx_status(). Then,
hidma_txn_is_success() will be called to use channel cookie
mchan->last_success to do additional DMA status check. Current code
assigns mchan->last_success after dma_cookie_complete(). This causes
a race condition of dma_cookie_status() returns DMA_COMPLETE before
mchan->last_success is assigned correctly. The race will cause
hidma_tx_status() return DMA_ERROR but the transaction is actually a
success. Moreover, in async_tx case, it will cause a timeout panic
in async_tx_quiesce().
Kernel panic - not syncing: async_tx_quiesce: DMA error waiting for
transaction
...
Call trace:
[<ffff000008089994>] dump_backtrace+0x0/0x1f4
[<ffff000008089bac>] show_stack+0x24/0x2c
[<ffff00000891e198>] dump_stack+0x84/0xa8
[<ffff0000080da544>] panic+0x12c/0x29c
[<ffff0000045d0334>] async_tx_quiesce+0xa4/0xc8 [async_tx]
[<ffff0000045d03c8>] async_trigger_callback+0x70/0x1c0 [async_tx]
[<ffff0000048b7d74>] raid_run_ops+0x86c/0x1540 [raid456]
[<ffff0000048bd084>] handle_stripe+0x5e8/0x1c7c [raid456]
[<ffff0000048be9ec>] handle_active_stripes.isra.45+0x2d4/0x550 [raid456]
[<ffff0000048beff4>] raid5d+0x38c/0x5d0 [raid456]
[<ffff000008736538>] md_thread+0x108/0x168
[<ffff0000080fb1cc>] kthread+0x10c/0x138
[<ffff000008084d34>] ret_from_fork+0x10/0x18
Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
In async_tx_test_ack(), it uses flags in struct dma_async_tx_descriptor
to check the ACK status. As hidma reuses the descriptor in a free list
when hidma_prep_dma_*(memcpy/memset) is called, the flag will keep ACKed
if the descriptor has been used before. This will cause a BUG_ON in
async_tx_quiesce().
kernel BUG at crypto/async_tx/async_tx.c:282!
Internal error: Oops - BUG: 0 1 SMP
...
task: ffff8017dd3ec000 task.stack: ffff8017dd3e8000
PC is at async_tx_quiesce+0x54/0x78 [async_tx]
LR is at async_trigger_callback+0x98/0x110 [async_tx]
This patch initializes flags in dma_async_tx_descriptor by the flags
passed from the caller when hidma_prep_dma_*(memcpy/memset) is called.
Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The context loaded only one time before channel running,but
currently sdma_config_channel() and dma_prep_* duplicated with
sdma_load_context(), so refine it to load context only one time
before channel running and reload after the channel terminated.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
We already need to zero out memory for dma_alloc_coherent(), as such
using dma_zalloc_coherent() is superflous. Phase it out.
This change was generated with the following Coccinelle SmPL patch:
@ replace_dma_zalloc_coherent @
expression dev, size, data, handle, flags;
@@
-dma_zalloc_coherent(dev, size, handle, flags)
+dma_alloc_coherent(dev, size, handle, flags)
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: re-ran the script on the latest tree]
Signed-off-by: Christoph Hellwig <hch@lst.de>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Tested-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
This issue was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This patch updates license to use SPDX-License-Identifier
instead of verbose license text.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Intel iDMA 32-bit doesn't have a concept of bus masters and thus
there is no need to setup any kind of masters in the CTL_LO register.
Moreover, the burst size for memory-to-memory transfer is not what is says,
we need to have a corrected list of possible sizes. Note, that
the size of 8 items, each of that up to 4 bytes, is chosen because of
maximum of 1/2 FIFO, which is 64 bytes on Intel Merrifield.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
For Intel iDMA 32-bit the channel can be drained on a suspend.
We need to reset the bit on the resume to return a status quo.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Here is a kinda big refactoring that should have been done
in the first place, when Intel iDMA 32-bit support appeared.
It splits operations which are different to Synopsys DesignWare and
Intel iDMA 32-bit controllers.
No functional change intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
All known devices, which use DT for configuration, support
memory-to-memory transfers. So enable it by default.
The rest two cases, i.e. Intel Quark and PPC460ex, instantiate DMA driver and
use its channels exclusively for hardware, which means there is no available
channel for any other purposes anyway.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The commit a9ddb575d6
("dmaengine: dw_dmac: Enhance device tree support")
introduces is_private property in uncertain understanding what does it mean.
First of all, documentation defines DMA_PRIVATE capability as
Documentation/crypto/async-tx-api.txt:
The DMA_PRIVATE capability flag is used to tag dma devices that should not be
used by the general-purpose allocator. It can be set at initialization time
if it is known that a channel will always be private. Alternatively,
it is set when dma_request_channel() finds an unused "public" channel.
A couple caveats to note when implementing a driver and consumer:
1/ Once a channel has been privately allocated it will no longer be
considered by the general-purpose allocator even after a call to
dma_release_channel().
2/ Since capabilities are specified at the device level a dma_device with
multiple channels will either have all channels public, or all channels
private.
Documentation/driver-api/dmaengine/provider.rst:
- DMA_PRIVATE
The devices only supports slave transfers, and as such isn't available
for async transfers.
The capability had been introduced by the commit 59b5ec2144
("dmaengine: introduce dma_request_channel and private channels")
and some code didn't changed from that times ever.
Taking into consideration above and the fact that on all known platforms
Synopsys DesignWare DMA engine is attached to serve slave transfers,
the DMA_PRIVATE capability must be enabled for this device unconditionally.
Otherwise, as rightfully noticed in drivers/dma/at_xdmac.c:
/*
* Without DMA_PRIVATE the driver is not able to allocate more than
* one channel, second allocation fails in private_candidate.
*/
because of of a caveats mentioned in above documentation excerpts.
So, remove conditional around DMA_PRIVATE followed by removal leftovers.
If someone wonders, DMA_PRIVATE can be not used if and only if the all channels
of the DMA controller are supposed to serve memory-to-memory like operations.
For example, EP93xx has two controllers, one of which can only perform
memory-to-memory transfers
Note, this change doesn't affect dmatest to be able to test such controllers.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (maintainer:SERIAL DRIVERS)
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
xilinx_vdma_start_transfer() is used only for VDMA IP, still it contains
conditional code on has_sg variable. has_sg is set only whenever the HW
does support SG mode, that is never true for VDMA IP.
This patch drops the never-taken branches.
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The AXIDMA and CDMA HW can be either direct-access or scatter-gather
version. These are SW incompatible.
The driver can handle both versions: a DT property was used to
tell the driver whether to assume the HW is in scatter-gather mode.
This patch makes the driver to autodetect this information. The DT
property is not required anymore.
No changes for VDMA.
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Whenever a single or cyclic transaction is prepared, the driver
could eventually split it over several SG descriptors in order
to deal with the HW maximum transfer length.
This could end up in DMA operations starting from a misaligned
address. This seems fatal for the HW if DRE (Data Realignment Engine)
is not enabled.
This patch eventually adjusts the transfer size in order to make sure
all operations start from an aligned address.
Cc: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This patch removes a bit of duplicated code by introducing a new
function that implements calculations for DMA copy size, and
prepares for changes to the copy size calculation that will
happen in following patches.
Suggested-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The name field is used for "apbdma.%d" which is rarely going to be
more than 10 bytes, so reduce the size from 30 to 12. This is only
being used by the interrupt registration, so is not critical to the
operation of the driver either.
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The buffer byte request length and counter are declared as signed integers
but the values should never be below zero, so make these unsigned integers
instead.
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The dma_desc->bytes_transferred counter tracks the number of bytes
moved by the DMA channel. This is then used to calculate the information
passed back in the in the tegra_dma_tx_status callback, which is usually
fine.
When the DMA channel is configured as continous, then the bytes_transferred
counter will increase over time and eventually overflow to become negative
so the residue count will become invalid and the ALSA sound-dma code will
report invalid hardware pointer values to the application. This results in
some users becoming confused about the playout position and putting audio
data in the wrong place.
To fix this issue, always ensure the bytes_transferred field is modulo the
size of the request. We only do this for the case of the cyclic transfer
done ISR as anyone attempting to move 2GiB of DMA data in one transfer
is unlikely.
Note, we don't fix the issue that we should /never/ transfer a negative
number of bytes so we could make those fields unsigned.
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
For avoiding false FIFO detection, check FIFO Error interrupt is
enabled prior raising any errors.
This will prevent having spurious FIFO error where it shouldn't.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
In stm32_mdma_probe, after reading the property "st,ahb-addr-masks", the
second call is not checked for failure. This time of check to time of use
case of "count" error is sent upstream.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Acked-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
While initializing the driver, the function platform_driver_register can
fail and return an error. Consistent with other invocations, this patch
returns the error upstream.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Acked-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
