Commit Graph

88 Commits

Author SHA1 Message Date
Benjamin Herrenschmidt 15e2a7218c fsi: sbefifo: Bump max command length
Otherwise cronus putmem fails istep and BML fails to upload skiboot

To do that, we still use our one-page command buffer for small commands
for speed, and for anything bigger, with a limit of 1MB plus a page,
we vmalloc a temporary buffer.

The limit was chosen because Cronus will break up any data transfer
into 1M chunks (the extra page is for the command header).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
2018-08-08 15:44:47 +10:00
Benjamin Herrenschmidt aa1221b258 fsi: scom: Fix NULL dereference
The chardev conversion forgot to copy the fsi_dev,
silly mistake, compounded by a testing mistake on
my side, this specific driver wasn't being tested
properly.

Fixes: d8f4587655 "fsi: scom: Convert to use the new chardev"
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-08-06 12:27:04 +10:00
Benjamin Herrenschmidt 9840fcd8cc fsi: Prevent multiple concurrent rescans
The bus scanning process isn't terribly good at parallel attempts
at rescanning the same bus. Let's have a per-master mutex protecting
the scanning process.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:58:12 +10:00
Benjamin Herrenschmidt d1dcd67825 fsi: Add cfam char devices
This aims to deprecate the "raw" sysfs file used for directly
accessing the CFAM and instead use a char device like the
other sub drivers.

Since it reworks the slave creation code and adds a cfam device
type, we also use the opportunity to convert the attributes
to attribute groups and add a couple more.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:58:05 +10:00
Benjamin Herrenschmidt d8f4587655 fsi: scom: Convert to use the new chardev
This converts FSI scom to use the new fsi-core controlled
chardev allocator and use a real cdev instead of a miscdev.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:57:55 +10:00
Benjamin Herrenschmidt 8b052dd64f fsi: sbefifo: Convert to use the new chardev
This converts FSI sbefifo to use the new fsi-core controlled
chardev allocator and use a real cdev instead of a miscdev.

One side effect is to fix the object lifetime by removing
the use of devm_kzalloc() for something that contains kobjects,
and using proper reference counting.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:57:31 +10:00
Benjamin Herrenschmidt 0ab5fe5374 fsi: Add new central chardev support
The various FSI devices (sbefifo, occ, scom, more to come)
currently use misc devices.

This is problematic as the minor device space for misc is
limited and there can be a lot of them. Also it limits our
ability to move them to a dedicated /dev/fsi directory or
to be smart about device naming and numbering.

It also means we have IDAs on every single of these drivers

This creates a common fsi "device_type" for the optional
/dev/fsi grouping and a dev_t allocator for all FSI devices.

"Legacy" devices get to use a backward compatible numbering
scheme (as long as chip id <16 and there's only one copy
of a given unit type per chip).

A single major number and a single IDA are shared for all
FSI devices.

This doesn't convert the FSI device drivers to use the new
scheme yet, they will be converted individually.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:57:23 +10:00
Benjamin Herrenschmidt 537052df22 fsi: master-ast-cf: Rename dump_trace() to avoid name collision
s390 defines a global dump_trace() symbol. Rename ours to
dump_ucode_trace() to avoid a collision in build tests.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-26 14:49:50 +10:00
Gustavo A. R. Silva 502defbb47 fsi: master-ast-cf: Fix memory leak
In case memory resources for *fw* were allocated, release them
before return.

Addresses-Coverity-ID: 1472044 ("Resource leak")
Fixes: 6a794a27da ("fsi: master-ast-cf: Add new FSI master using Aspeed ColdFire")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-26 09:56:17 +10:00
Benjamin Herrenschmidt 375cac7010 fsi: master-ast-cf: Mask unused bits in RTAG/RCRC
Then reading the RTAG/RCRC "registers" from the coprocessor after
a command is complete, mask out the top bits, only keep the relevant
bits. Microcode v5 will leave garbage in those top bits as a
result of a performance optimization.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
2018-07-25 16:04:53 +10:00
Benjamin Herrenschmidt d0cff240b8 fsi: master-ast-cf: Fix build warnings on 64-bit platforms
A couple of places forgot the 'z' qualifier for dev_dbg
when printing a size_t

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-24 16:35:03 +10:00
Benjamin Herrenschmidt 0a213777d1 fsi: Add support for device-tree provided chip IDs
They get retrieved from the device-tree and exposed
as an attribute in sysfs

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-23 16:27:32 +10:00
Benjamin Herrenschmidt 4fcdc2d1b0 fsi: sbefifo: Fix inconsistent use of ffdc mutex
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>
2018-07-23 16:27:32 +10:00
Benjamin Herrenschmidt 6a794a27da fsi: master-ast-cf: Add new FSI master using Aspeed ColdFire
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>
2018-07-23 15:22:52 +10:00
Benjamin Herrenschmidt fea9cf321c fsi: Move various master definitions to a common header
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>
2018-07-12 12:06:02 +10:00
Benjamin Herrenschmidt 8ef9ccf810 fsi: master-gpio: Add missing release function
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>
2018-07-12 12:05:22 +10:00
Benjamin Herrenschmidt 265aac26bc fsi: Don't use device_unregister() in fsi_master_register()
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>
2018-07-12 12:05:11 +10:00
Benjamin Herrenschmidt 55382d301f fsi: master-gpio: Remove "GPIO" prefix on some definitions
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
2018-07-12 12:04:24 +10:00
Benjamin Herrenschmidt 8b2e475113 fsi: master-gpio: Remove unused definitions
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
2018-07-12 12:02:59 +10:00
Benjamin Herrenschmidt 777fd524ba fsi: master-gpio: Add more tracepoints
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>
2018-07-12 12:02:31 +10:00
Benjamin Herrenschmidt 75854c148f fsi: master-gpio: Add support for link_config
To configure the send and echo delays

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
2018-07-12 12:00:11 +10:00
Benjamin Herrenschmidt edc2485148 fsi: master-gpio: Rename and adjust send delay
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>
2018-07-12 11:59:48 +10:00
Benjamin Herrenschmidt a2e7da86cc fsi: Add mechanism to set the tSendDelay and tEchoDelay values
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>
---
2018-07-12 11:59:13 +10:00
Benjamin Herrenschmidt 935f963638 fsi: Move code around to avoid forward declaration
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>
2018-07-12 11:58:25 +10:00
Benjamin Herrenschmidt d5c66e61e7 fsi: sbefifo: Fix checker warning about late NULL check
"dev" is dereferences before it's checked.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-12 11:53:37 +10:00
Guenter Roeck 32f7f89d30 fsi/sbefifo: Add dependency on OF_ADDRESS
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>
2018-07-12 11:51:19 +10:00
Eddie James c00bac8876 fsi: sbefifo: Add missing mutex_unlock
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>
2018-07-12 11:51:12 +10:00
Benjamin Herrenschmidt 6b293258cd fsi: scom: Major overhaul
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>
2018-06-18 15:11:53 +10:00
Benjamin Herrenschmidt f143304442 fsi: scom: Add register definitions
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>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt 5a3c2f7656 fsi: scom: Fixup endian annotations
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>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt bd21336457 fsi: scom: Whitespace fixes
No functional changes

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt 162c394673 fsi: scom: Add mutex around FSI2PIB accesses
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>
2018-06-18 14:33:56 +10:00
Joel Stanley 11454d6dc8 fsi: core: Fix sparse warnings
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:606:15: warning: incorrect type in assignment (different base types)
fsi-core.c:606:15:    expected unsigned int [unsigned] [assigned] [usertype] smode
fsi-core.c:606:15:    got restricted __be32 [usertype] <noident>
fsi-core.c:492:28: warning: expression using sizeof(void)
fsi-core.c:520:29: warning: expression using sizeof(void)
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:706:24: warning: incorrect type in assignment (different base types)
fsi-core.c:706:24:    expected unsigned int [unsigned] [usertype] llmode
fsi-core.c:706:24:    got restricted __be32 [usertype] <noident>

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-06-18 14:33:56 +10:00
Joel Stanley fbdb5eac5c fsi: master-hub: Fix sparse warnings
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>
2018-06-18 14:33:56 +10:00
Joel Stanley 2992513877 fsi: sbefifo: Fix sparse warnings
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>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt a9ef97d098 fsi: sbefifo: Remove unneeded semicolon
Spotted by kbuild-test-bot

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-06-14 14:02:27 +10:00
Benjamin Herrenschmidt 9f4a8a2d7f fsi/sbefifo: Add driver for the SBE FIFO
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>
---
2018-06-12 14:05:39 +10:00
Eddie James 52b7116e88 fsi: scom: Remove PIB reset during probe
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>
2018-06-12 14:05:34 +10:00
Jeremy Kerr 26d79b272d fsi/master-gpio: Replace bit_bit lock with IRQ disable/enable
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>
2018-06-12 14:05:28 +10:00
Benjamin Herrenschmidt c49e34401a fsi/fsi-master-gpio: More error handling cleanup
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>
2018-06-12 14:05:23 +10:00
Benjamin Herrenschmidt 4e56828a5d fsi/fsi-master-gpio: Implement CRC error recovery
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.
2018-06-12 14:05:16 +10:00
Jeremy Kerr 0e82e5c1fa fsi/gpio: Use relative-addressing commands
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>
2018-06-12 14:05:10 +10:00
Jeremy Kerr 8193fb4451 fsi/gpio: Include command build in locked section
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>
2018-06-12 14:05:04 +10:00
Benjamin Herrenschmidt f3ca4834ac fsi/fsi-master-gpio: Delay sampling of FSI data input
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>
2018-06-12 14:04:59 +10:00
Benjamin Herrenschmidt b632642e4c fsi/fsi-master-gpio: Reduce dpoll clocks
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>
2018-06-12 14:04:52 +10:00
Benjamin Herrenschmidt 97a4e5c95b fsi/fsi-master-gpio: Reduce turnaround clocks
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>
2018-06-12 14:04:46 +10:00
Benjamin Herrenschmidt bc1099d2b2 fsi/fsi-master-gpio: Add "no-gpio-delays" option
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>
2018-06-12 14:04:41 +10:00
Benjamin Herrenschmidt 5d0d16f135 fsi/fsi-master-gpio: Sample input data on different clock phase
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>
2018-06-12 14:04:34 +10:00
Jeremy Kerr e5538139e0 fsi: gpio: Use a mutex to protect transfers
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>
2018-06-12 14:04:26 +10:00
Andrew Jeffery e212ab47bd fsi: gpio: Remove unused 'id' variable
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>
2018-06-12 14:04:21 +10:00