The assignment of xfer_len to cmd->read_len appears to be redundant
as the next statement re-assigns the value 0 to it. Clean up the
code by removing the redundant first assignment.
Addresses-Coverity: ("Unused value")
Fixes: dd3c52846d ("i3c: master: svc: Add Silvaco I3C master driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210224151349.202332-1-colin.king@canonical.com
Disabling all event calls is already handled by the core right before
starting the DAA process. Do not do it again when the DAA process
completes, it is redundant.
Fixes: 1dd728f5d4 ("i3c: master: Add driver for Synopsys DesignWare IP")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201228105501.6104-1-miquel.raynal@bootlin.com
Add support for Silvaco I3C dual-role IP. The master role is supported
in SDR mode only. I2C transfers have not been tested but are shared
because they are very close to the I3C transfers in terms of register
configuration.
The IBI processing follows this logic:
- When a slave advertizes an interrupt (SDA pulled low) an interrupt
gets generated by the master. This time is unbounded and may be
deferred.
- The IRQ handler itself does not process anything: it only queues a
work that will be run in non-atomic context. This is needed because
short wait periods must be experienced.
- The IBI job is divided in two parts: the first one is "critical" in
the sense that it may not support getting interrupted. If this
happens, after this first section the driver checks the master error
register and depending on its content either flushes everything and
errors out, or ends the processing (this second section may be
interrupted).
- If the critical section got interrupted, the slave will
automatically respin it's IBI request when it will be allowed to.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210121101808.14654-6-miquel.raynal@bootlin.com
The MIPI i3c HCI driver makes use of IOMEM functions like
devm_platform_ioremap_resource(), which are only available if
CONFIG_HAS_IOMEM is defined.
This causes the driver to be enabled under make ARCH=um allyesconfig,
even though it won't build.
By adding a dependency on HAS_IOMEM, the driver will not be enabled on
architectures which don't support it.
Fixes: 9ad9a52cce ("i3c/master: introduce the mipi-i3c-hci driver")
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210127040636.1535722-1-davidgow@google.com
Clang warns:
../drivers/i3c/master/mipi-i3c-hci/core.c:780:21: warning: attribute
declaration must precede definition [-Wignored-attributes]
static const struct __maybe_unused of_device_id i3c_hci_of_match[] = {
^
../include/linux/compiler_attributes.h:267:56: note: expanded from macro
'__maybe_unused'
#define __maybe_unused __attribute__((__unused__))
^
../include/linux/mod_devicetable.h:262:8: note: previous definition is
here
struct of_device_id {
^
1 warning generated.
'struct of_device_id' should not be split, as it is a type. Move the
__maybe_unused attribute after the static and const qualifiers so that
there are no warnings about this variable, period.
Fixes: 95393f3e07 ("i3c/master/mipi-i3c-hci: quiet maybe-unused variable warning")
Link: https://github.com/ClangBuiltLinux/linux/issues/1221
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201222025931.3043480-1-natechancellor@gmail.com
If CONFIG_OF is disabled then the matching table is notreferenced.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
The variable next_addr is not initialized and is being used in a call
to i3c_master_get_free_addr as a starting point to find the next address.
Fix this by initializing next_addr to 0 to avoid an uninitialized garbage
starting address from being used.
Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: 9ad9a52cce ("i3c/master: introduce the mipi-i3c-hci driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20201124123504.396249-1-colin.king@canonical.com
This adds basic support for hardware implementing the MIPI I3C HCI
specification. This driver is currently limited by the capabilities
of the I3C subsystem, meaning things like scheduled commands,
auto-commands and NCM mode are not yet supported.
This supports version 1.0 of the MIPI I3C HCI spec, as well as the
imminent release of version 1.1. Support for draft version 2.0 of the
spec is also largely included with the caveat that future adjustments
to this code are likely as the spec is still a work in progress.
This is also lightly tested as actual hardware is still very scarce,
even for HCI v1.0. Hence the EXPERIMENTAL tag. Further contributions
to this driver are expected once vendor implementations and new I3C
devices become available.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20201111220510.3622216-3-nico@fluxnic.net
* Fix an error path in the cadence driver
-----BEGIN PGP SIGNATURE-----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=yC+2
-----END PGP SIGNATURE-----
Merge tag 'i3c/for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux
Pull i3c updates from Boris Brezillon:
- Fix DAA for the pre-reserved address case
- Fix an error path in the cadence driver
* tag 'i3c/for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
i3c: master: Fix error return in cdns_i3c_master_probe()
i3c: master: fix for SETDASA and DAA process
i3c: master add i3c_master_attach_boardinfo to preserve boardinfo
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20200227131307.GA24935@embeddedor
For today the reattach function only update the device address on the
controller.
Update the location to the first available too, will optimize the
enumeration process avoiding additional checks to keep the available
positions on address table consecutive.
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Use devm_platform_ioremap_resource() to simplify code.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Use devm_platform_ioremap_resource() to simplify code.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
This patch adds support for THD_DEL (Data Hold Delay) to Cadence
I3C master constoller driver.
As per MIPI I3C Specification 1.0, Table 75 (page 142) defines
non-zero minimal tHD_PP timing on master output (Fig 65). This
setting allows to meet this timing on master's soc outputs,
regardless of PCB balancing.
Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
I need to store address and lvr value for I2C devices without static definition
in DT. This allows secondary master to transmit DEFSLVS command properly.
Main changes between v4 and v5:
- Change in defslvs to use addr and lvr from i2c_dev_desc structure
- Change in CDNS and DW drivers to use addr and lvr from i2c_dev_desc structure
Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
This simplifies and standardizes slot manipulation code
by using for_each_set_bit() library function.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
* Add support for limited bus mode
* Fix the Cadence DT binding doc
* Use struct_size() to allocate a DEFSLVS packet
-----BEGIN PGP SIGNATURE-----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=Uj8o
-----END PGP SIGNATURE-----
Merge tag 'i3c/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux
Pull ic3 updates from Boris Brezillon:
- Drop support for 10-bit I2C addresses
- Add support for limited bus mode
- Fix the Cadence DT binding doc
- Use struct_size() to allocate a DEFSLVS packet
* tag 'i3c/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
i3c: master: Use struct_size() helper
dt-bindings: i3c: cdns: Use correct cells for I2C device
i3c: dw: add limited bus mode support
i3c: add mixed limited bus mode
i3c: fix i2c and i3c scl rate by bus mode
dt-bindings: i3c: Document dropped support for I2C 10 bit devices
i3c: Drop support for I2C 10 bit addresing
This patch add limited bus mode support for DesignWare i3c master
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
This patch drops support for I2C devices with 10 bit addressing. When I2C
device with 10 bit address is defined in DT, I3C master registration fails.
Address space for I2C devices has been reduced and ->i2c_funcs() hook has been
removed.
Because this patch series dropped support for 10 bit I2C devices, support is
also dropped in Cadence I3C master driver and Synopsys DesignWare I3C master
driver.
Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Remove dead code in the DW driver
-----BEGIN PGP SIGNATURE-----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=/U9S
-----END PGP SIGNATURE-----
Merge tag 'i3c/for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux
Pull i3c update from Boris Brezillon:
- Fix a shift wrap bug in the core
- Remove dead code in the DW driver
* tag 'i3c/for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
i3c: Fix a shift wrap bug in i3c_bus_set_addr_slot_status()
i3c: master: dw: remove dead code from dw_i3c_master_*_xfers()
The controller was being disabled incorrectly. The correct way is to clear
the DEV_CTRL_ENABLE bit.
Fix this by clearing this bit.
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: <stable@vger.kernel.org>
Fixes: 1dd728f5d4 ("i3c: master: Add driver for Synopsys DesignWare IP")
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Detected by CoverityScan (Event result_independent_of_operands):
"(i3c_xfers + i).len > 65536" is always false regardless of the values
of its operands. This occurs as the logical operand of "if"
"(i2c_xfers + i).len > 65536" is always false regardless of the values
of its operands. This occurs as the logical operand of "if"
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
- Update the I3C entries in MAINTAINERS to add an IRC chan
-----BEGIN PGP SIGNATURE-----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=Ijxi
-----END PGP SIGNATURE-----
Merge tag 'i3c/for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux
Pull i3c updates from Boris Brezillon:
- Add a /* fall-through */ comment in the dw-i3c-master driver
- Update the I3C entries in MAINTAINERS to add an IRC chan
* tag 'i3c/for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
i3c: master: dw-i3c-master: mark expected switch fall-through
MAINTAINERS: Add an IRC channel for the I3C subsystem
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.
This patch fixes the following warning:
drivers/i3c/master/dw-i3c-master.c: In function ‘dw_i3c_master_bus_init’:
drivers/i3c/master/dw-i3c-master.c:603:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (ret)
^
drivers/i3c/master/dw-i3c-master.c:605:2: note: here
case I3C_BUS_MODE_PURE:
^~~~
Warning level 3 was used: -Wimplicit-fallthrough=3
This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
In dw_i3c_master_irq_handler(), we already have gotten
&master->xferqueue.lock, if we try to get the same lock again in
dw_i3c_master_dequeue_xfer(), deadlock happens.
We fix this issue by introduing dw_i3c_master_dequeue_xfer_locked()
which does all what dw_i3c_master_dequeue_xfer() does without trying
to lock &master->xferqueue.lock.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Acked-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
This patch fix i3c_attach/reattach functions.
During the i3c_attach the driver ignores the static address used for
SETDASA CCC command.
During the i3c_reattach the driver doesn't update master->addrs[data->index]
with new address if old_dyn_addr = 0.
Fixes: 1dd728f5d4 ("i3c: master: Add driver for Synopsys DesignWare IP")
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
This patch fixes I2C transfers in Cadence I3C master driver.
There was no way to queue more than one I2C transfer before.
Fixes: 603f2bee2c ("i3c: master: Add driver for Cadence IP")
Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
The masking operation on status is using a bitwise 'or' rather than
a bitwise 'and' operator, and hence the result is always non-zero
which is probably not what is intended. Fix this by using the correct
operator.
Detected by CoverityScan, CID#1475523 ("Wrong operator used")
Fixes: 88acc98a712a ("i3c: master: Add driver for Synopsys DesignWare IP")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/i3c/master/i3c-master-cdns.c: In function 'cdns_i3c_master_do_daa':
drivers/i3c/master/i3c-master-cdns.c:1137:16: warning:
variable 'old_i3c_scl_lim' set but not used [-Wunused-but-set-variable]
It never used since introdution in commit
acfab7d324b2 ("i3c: master: Add driver for Cadence IP")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Add core infrastructure to support I3C in Linux and document it.
This infrastructure adds basic I3C support. Advanced features will be
added afterwards.
There are a few design choices that are worth mentioning because they
impact the way I3C device drivers can interact with their devices:
- all functions used to send I3C/I2C frames must be called in
non-atomic context. Mainly done this way to ease implementation, but
this is not set in stone, and if anyone needs async support, new
functions can be added later on.
- the bus element is a separate object, but it's tightly coupled with
the master object. We thus have a 1:1 relationship between i3c_bus
and i3c_master_controller objects, and if 2 master controllers are
connected to the same bus and both exposed to the same Linux instance
they will appear as two distinct busses, and devices on this bus will
be exposed twice.
- I2C backward compatibility has been designed to be transparent to I2C
drivers and the I2C subsystem. The I3C master just registers an I2C
adapter which creates a new I2C bus. I'd say that, from a
representation PoV it's not ideal because what should appear as a
single I3C bus exposing I3C and I2C devices here appears as 2
different buses connected to each other through the parenting (the
I3C master is the parent of the I2C and I3C busses).
On the other hand, I don't see a better solution if we want something
that is not invasive.
Missing features:
- I3C HDR modes are not supported
- no support for multi-master and the associated concepts (mastership
handover, support for secondary masters, ...)
- I2C devices can only be described using DT because this is the only
use case I have. However, the framework can easily be extended with
ACPI and board info support
- I3C slave framework. This has been completely omitted, but shouldn't
have a huge impact on the I3C framework because I3C slaves don't see
the whole bus, it's only about handling master requests and generating
IBIs. Some of the struct, constant and enum definitions could be
shared, but most of the I3C slave framework logic will be different
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Colin Ian King
Linus Torvalds
Miquel Raynal
David Gow
Nathan Chancellor
Nicolas Pitre
Jing Xiangfeng
Gustavo A. R. Silva
Gustavo A. R. Silva
Vitor Soares
Yangtao Li
Przemyslaw Gaj
Andy Shevchenko
Thomas Gleixner
Jisheng Zhang
Christophe JAILLET
YueHaibing
Boris Brezillon