Some of the exit path missed the unlock. Move the mutex to
an outer function to avoid the problem completely
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The Aspeed AST2x00 can contain a ColdFire v1 coprocessor which
is currently unused on OpenPower systems.
This adds an alternative to the fsi-master-gpio driver that
uses that coprocessor instead of bit banging from the ARM
core itself. The end result is about 4 times faster.
The firmware for the coprocessor and its source code can be
found at https://github.com/ozbenh/cf-fsi and is system specific.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This moves the definitions for various protocol details
(message & response codes, delays etc...) out of
fsi-master-gpio.c to fsi-master.h in order to share them
with other master implementations.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
The embedded struct device needs a release function to be
able to successfully remove the driver.
We remove the devm_gpiod_put() as they are unnecessary
(the resources will be released automatically) and because
fsi_master_unregister() will cause the master structure to
be freed.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
In the error path of fsi_master_register(), we currently
use device_unregister(). This will cause the last reference
to the structure to be dropped, thus freeing the enclosing
structure, which isn't what the callers want.
Use device_del() instead so that we return to the caller
with a refcount of 1. The caller can then assume that it
must use put_device() after a call to fsi_master_register()
regardless of whether the latter suceeded or failed.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Some definitions are generic to the FSI protocol or any
give master implementation. Rename them to remove the
"GPIO" prefix in preparation for moving them to a common
header.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
# Conflicts:
# drivers/fsi/fsi-master-gpio.c
This adds a few more tracepoints that have proven useful when
debugging issues with the FSI bus.
This also makes echo_delay() use clock_zeros() instead of
open-code it in order to share the tracepoint.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
What the driver called "FSI_GPIO_PRIME_SLAVE_CLOCKS" is what
the FSI spec calls tSendDelay and should be 16 clocks by
default.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Those values control the amount of "dummy" clocks between commands and
between a command and its response.
This adds a way to configure them from sysfs (to be later extended to
defaults in the device-tree). The default remains 16 (the HW default).
This is only supported if the backend supports the new link_config()
callback to configure the generation of those delays.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
---
Move fsi_slave_set_smode() and its helpers to before it's
first user and remove the corresponding forward declaration.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
"dev" is dereferences before it's checked.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The driver calls of_platform_device_create() which is only available
if OF_ADDRESS is enabled. When building sparc64 images, this results
in
ERROR: "of_platform_device_create" [drivers/fsi/fsi-sbefifo.ko] undefined!
Fixes: 9f4a8a2d7f ("fsi/sbefifo: Add driver for the SBE FIFO")
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
There was no unlock of the FFDC mutex.
Fixes: 9f4a8a2d7f ("fsi/sbefifo: Add driver for the SBE FIFO")
Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This was too hard to split ... this adds a number of features
to the SCOM user interface:
- Support for indirect SCOMs
- read()/write() interface now handle errors and retries
- New ioctl() "raw" interface for use by debuggers
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Add a few more register and bit definitions, also define and use
SCOM_READ_CMD (which is 0 but it makes the code clearer)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
Use the proper annotated type __be32 and fixup the
accessor used for get_scom()
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
Otherwise, multiple clients can open the driver and attempt
to access the PIB at the same time, thus clobbering each other
in the process.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
fsi-master-hub.c:128:13: warning: incorrect type in assignment (different base types)
fsi-master-hub.c:128:13: expected unsigned int [unsigned] [usertype] cmd
fsi-master-hub.c:128:13: got restricted __be32 [usertype] <noident>
fsi-master-hub.c:208:13: warning: incorrect type in assignment (different base types)
fsi-master-hub.c:208:13: expected restricted __be32 [addressable] [assigned] [usertype] reg
fsi-master-hub.c:208:13: got int
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
fsi-sbefifo.c:547:58: warning: incorrect type in argument 2 (different base types)
fsi-sbefifo.c:547:58: expected restricted __be32 [usertype] *word
fsi-sbefifo.c:547:58: got unsigned int *<noident>
fsi-sbefifo.c:635:16: warning: incorrect type in assignment (different base types)
fsi-sbefifo.c:635:16: expected unsigned int [unsigned] <noident>
fsi-sbefifo.c:635:16: got restricted __be32 [usertype] <noident>
fsi-sbefifo.c:636:16: warning: incorrect type in assignment (different base types)
fsi-sbefifo.c:636:16: expected unsigned int [unsigned] <noident>
fsi-sbefifo.c:636:16: got restricted __be32 [usertype] <noident>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This driver provides an in-kernel and a user API for accessing
the command FIFO of the SBE (Self Boot Engine) of the POWER9
processor, via the FSI bus.
It provides an in-kernel interface to submit command and receive
responses, along with a helper to locate and analyse the response
status block. It's a simple synchronous submit() type API.
The user interface uses the write/read interface that an earlier
version of this driver already provided, however it has some
specific limitations in order to keep the driver simple and
avoid using up a lot of kernel memory:
- The user should perform a single write() with the command and
a single read() to get the response (with a buffer big enough
to hold the entire response).
- On a write() the command is simply "stored" into a kernel buffer,
it is submitted as one operation on the subsequent read(). This
allows to have the code write directly from the FIFO into the user
buffer and avoid hogging the SBE between the write() and read()
syscall as it's critical that the SBE be freed asap to respond
to the host. An extra write() will simply replace the previously
written command.
- A write of a single 4 bytes containing the value 0x52534554
in big endian will trigger a reset request. No read is necessary,
the write() call will return when the reset has been acknowledged
or times out.
- The command is limited to 4K bytes.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
---
The PIB reset causes problems for the running P9 chip. The reset
shouldn't be performed by this driver.
Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
We currently use a spinlock (bit_lock) around operations that clock bits
out of the FSI bus, and a mutex to protect against simultaneous access
to the master.
This means that bit_lock isn't needed for mutual exlusion, only to
prevent timing issues when clocking bits out.
To reflect this, this change converts bit_lock to just the
local_irq_save/restore operation.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Remove calls to the empty and useless fsi_master_gpio_error()
function, and report CRC errors as "FSI_ERR_NO_SLAVE" when
reading an all 1's response.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
The FSI protocol defines two modes of recovery from CRC errors,
this implements both:
- If the device returns an ECRC (it detected a CRC error in the
command), then we simply issue the command again.
- If the master detects a CRC error in the response, we send
an E_POLL command which requests a resend of the response
without actually re-executing the command (which could otherwise
have unwanted side effects such as dequeuing a FIFO twice).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
---
Note: This was actually tested by removing some of my fixes, thus
causing us to hit occasional CRC errors during high LPC activity.
FSI CFAMs support shorter commands that use a relative (or same) address
as the last. This change introduces a last_addr to the master state, and
uses it for subsequent reads/writes, and performs relative addressing
when a subsequent read/write is in range.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
For implementing relative addressing mode, we'll need to build a command
that is coherent with CFAM state. To do that, include the
build_command_* functions in the locked section of read/write/term.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Most SoC GPIO implementations, including the Aspeed one, have
synchronizers on the GPIO inputs. This means that the value
read from a GPIO is a couple of clocks old, from whatever clock
source feeds those synchronizers.
In practice, this means that in no-delay mode, we are using a
value that can potentially be a bit too old and too close to
the clock edge establishing the data on the other side of the link.
The voltage converters we use on some systems make this worse
and sensitive to things like voltage fluctuations etc... This is,
we believe, the cause of occasional CRC errors encountered during
heavy activity on the LPC bus.
This is fixed by introducing a dummy GPIO read before the actual
data read. It slows down SBEFIFO by about 15% (less than any delay
primitive) and the end result is so far solid.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
FSI_GPIO_DPOLL_CLOCKS is the number of clocks before sending
a DPOLL command after receiving a BUSY status. It should be
at least tSendDelay (16 clocks).
According to comments in the code, it needs to also be at least
21 clocks due to HW issues.
It's currently 100 clocks which impacts performances negatively
in some cases. Reduces it in half to 50 clocks which seems to
still be solid.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
FSI_GPIO_PRIME_SLAVE_CLOCKS is the number of clocks if the
"idle" phase between the end of a response and the beginning
of the next one. It corresponds to tSendDelay in the FSI
specification.
The default value in the slave is 16 clocks. 100 is way overkill
and significantly reduces the driver performance.
This changes it to 20 (which gives the HW a bit of margin still
just in case).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
This adds support for an optional device-tree property that
makes the driver skip all the delays around clocking the
GPIOs and set it in the device-tree of common POWER9 based
OpenPower platforms.
This useful on chips like the AST2500 where the GPIO block is
running at a fairly low clock frequency (25Mhz typically). In
this case, the delays are unnecessary and due to the low
precision of the timers, actually quite harmful in terms of
performance.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
We currently sample the input data right after we toggle the
clock low, then high. The slave establishes the data on the
rising edge, so this is not ideal. We should sample it on
the low phase instead.
This currently works because we have an extra delay, but subsequent
patches will remove it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Reduce time spent with interrupts disabled by limiting the critical
sections to bitbanging FSI symbols. We only need to ensure exclusive use
of the bus for an entire transfer, not that the transfer be performed in
atomic context.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
An observation from trace output of the existing FSI tracepoints was
that the remote device was sometimes reporting as busy. Add a new
tracepoint reporting the busy count in order to get a better grip on how
often this is the case.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Eddie James <eajames@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Prior to scanning a master check if the optional property
no-scan-on-init is present. If it is then avoid scanning. This is
necessary in cases where a master scan could interfere with another
FSI master on the same bus.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Once we call fsi_master_unregister, the core will put_device,
potentially freeing the hub master. This change adds a comment
explaining the lifetime of an allocated fsi_master.
We then add a reference from the driver to the hub master, so it stays
around until we've finished ->remove().
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To reduce amount of console output during boot / power up make
all normal path scan related messages debug type.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change populates device tree nodes for scanned FSI slaves and
engines. If the master populates ->of_node of the FSI master device,
we'll look for matching slaves, and under those slaves we'll look for
matching engines.
This means that FSI drivers will have their ->of_node pointer populated
if there's a corresponding DT node, which they can use for further
device discover.
Presence of device tree nodes is optional, and only required for
fsi device drivers that need extra properties, or subordinate devices,
to be enumerated.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Address checker fixed to allow one and two byte reads/writes.
Address alignments for each size verified.
Signed-off-by: Edward James <eajames@us.ibm.com>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change introduces an 'external mode' for GPIO-based FSI masters,
allowing the clock and data lines to be driven by an external source.
For example, external mode is selected by a user when an external debug
device is attached to the FSI pins.
To do this, we need to set specific states for the trans, mux and enable
GPIOs, and prevent access to clk & data from the FSI core code (by
returning EBUSY).
External mode is controlled by a sysfs attribute, so add the relevant
information to Documentation/ABI/
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, we perform GPIO accesses in fsi_master_gpio_break and
fsi_master_link_enable, without holding cmd_lock. This change adds the
appropriate locking.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We'll want non-core fsi code to trigger a rescan, so introduce a
non-static fsi_master_rescan() function. Use this for the existing
unscan/scan behaviour too.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No need to get into the submenu to disable all FSI-related config entries
Signed-off-by: Vincent Legoll <vincent.legoll@gmail.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The functions fsi_slave_report_and_clear_errors and fsi_slave_handle_error
are local to the source and do not need to be in global scope, so make
them static.
Cleans up sparse warnings:
symbol 'fsi_slave_report_and_clear_errors' was not declared. Should it
be static?
symbol 'fsi_slave_handle_error' was not declared. Should it be static?
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reset causes problems for operations requiring multiple scoms (e.g. i2c
over scom). Instead, reset scom engine during probe.
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
