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2018-12-02fsi: Add On-Chip Controller (OCC) driverEddie James3-0/+610
The OCC is a device embedded on a POWER processor that collects and aggregates sensor data from the processor and system. The OCC can provide the raw sensor data as well as perform thermal and power management on the system. This driver provides an atomic communications channel between a service processor (e.g. a BMC) and the OCC. The driver is dependent on the FSI SBEFIFO driver to get hardware access through the SBE to the OCC SRAM. Commands are issued to the SBE to send or fetch data to the SRAM. Signed-off-by: Eddie James <eajames@linux.ibm.com> Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2018-11-26fsi: fsi-scom.c: Remove duplicate headerBrajeswar Ghosh1-1/+0
Remove linux/cdev.h which is included more than once Signed-off-by: Brajeswar Ghosh <brajeswar.linux@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-11-26fsi: master-ast-cf: select GENERIC_ALLOCATORArnd Bergmann1-0/+1
In randconfig builds without CONFIG_GENERIC_ALLOCATOR, this driver fails to link: ERROR: "gen_pool_alloc_algo" [drivers/fsi/fsi-master-ast-cf.ko] undefined! ERROR: "gen_pool_fixed_alloc" [drivers/fsi/fsi-master-ast-cf.ko] undefined! ERROR: "of_gen_pool_get" [drivers/fsi/fsi-master-ast-cf.ko] undefined! ERROR: "gen_pool_free" [drivers/fsi/fsi-master-ast-cf.ko] undefined! Select the dependency as all other users do. Fixes: 6a794a27daca ("fsi: master-ast-cf: Add new FSI master using Aspeed ColdFire") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-10-24iov_iter: Separate type from direction and use accessor functionsDavid Howells1-2/+2
In the iov_iter struct, separate the iterator type from the iterator direction and use accessor functions to access them in most places. Convert a bunch of places to use switch-statements to access them rather then chains of bitwise-AND statements. This makes it easier to add further iterator types. Also, this can be more efficient as to implement a switch of small contiguous integers, the compiler can use ~50% fewer compare instructions than it has to use bitwise-and instructions. Further, cease passing the iterator type into the iterator setup function. The iterator function can set that itself. Only the direction is required. Signed-off-by: David Howells <dhowells@redhat.com>
2018-08-08fsi: sbefifo: Bump max command lengthBenjamin Herrenschmidt1-7/+32
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>
2018-08-06fsi: scom: Fix NULL dereferenceBenjamin Herrenschmidt1-0/+1
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: d8f4587655f9 "fsi: scom: Convert to use the new chardev" Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27fsi: Prevent multiple concurrent rescansBenjamin Herrenschmidt2-2/+16
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>
2018-07-27fsi: Add cfam char devicesBenjamin Herrenschmidt1-51/+213
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>
2018-07-27fsi: scom: Convert to use the new chardevBenjamin Herrenschmidt1-50/+80
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>
2018-07-27fsi: sbefifo: Convert to use the new chardevBenjamin Herrenschmidt1-29/+55
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>
2018-07-27fsi: Add new central chardev supportBenjamin Herrenschmidt2-2/+108
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>
2018-07-26fsi: master-ast-cf: Rename dump_trace() to avoid name collisionBenjamin Herrenschmidt1-5/+5
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>
2018-07-26fsi: master-ast-cf: Fix memory leakGustavo A. R. Silva1-2/+4
In case memory resources for *fw* were allocated, release them before return. Addresses-Coverity-ID: 1472044 ("Resource leak") Fixes: 6a794a27daca ("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>
2018-07-25fsi: master-ast-cf: Mask unused bits in RTAG/RCRCBenjamin Herrenschmidt1-2/+2
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> ---
2018-07-24fsi: master-ast-cf: Fix build warnings on 64-bit platformsBenjamin Herrenschmidt1-2/+2
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>
2018-07-23fsi: Add support for device-tree provided chip IDsBenjamin Herrenschmidt1-0/+24
They get retrieved from the device-tree and exposed as an attribute in sysfs Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-23fsi: sbefifo: Fix inconsistent use of ffdc mutexBenjamin Herrenschmidt1-4/+9
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>
2018-07-23fsi: master-ast-cf: Add new FSI master using Aspeed ColdFireBenjamin Herrenschmidt4-0/+1605
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>
2018-07-12fsi: Move various master definitions to a common headerBenjamin Herrenschmidt2-29/+33
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>
2018-07-12fsi: master-gpio: Add missing release functionBenjamin Herrenschmidt1-18/+35
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>
2018-07-12fsi: Don't use device_unregister() in fsi_master_register()Benjamin Herrenschmidt1-5/+2
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>
2018-07-12fsi: master-gpio: Remove "GPIO" prefix on some definitionsBenjamin Herrenschmidt1-34/+36
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
2018-07-12fsi: master-gpio: Remove unused definitionsBenjamin Herrenschmidt1-6/+0
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Joel Stanley <joel@jms.id.au>
2018-07-12fsi: master-gpio: Add more tracepointsBenjamin Herrenschmidt1-6/+10
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>
2018-07-12fsi: master-gpio: Add support for link_configBenjamin Herrenschmidt1-2/+25
To configure the send and echo delays Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Joel Stanley <joel@jms.id.au>
2018-07-12fsi: master-gpio: Rename and adjust send delayBenjamin Herrenschmidt1-3/+6
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>
2018-07-12fsi: Add mechanism to set the tSendDelay and tEchoDelay valuesBenjamin Herrenschmidt2-18/+93
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> ---
2018-07-12fsi: Move code around to avoid forward declarationBenjamin Herrenschmidt1-48/+46
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>
2018-07-12fsi: sbefifo: Fix checker warning about late NULL checkBenjamin Herrenschmidt1-2/+5
"dev" is dereferences before it's checked. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-12fsi/sbefifo: Add dependency on OF_ADDRESSGuenter Roeck1-0/+1
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: 9f4a8a2d7f9d ("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>
2018-07-12fsi: sbefifo: Add missing mutex_unlockEddie James1-0/+1
There was no unlock of the FFDC mutex. Fixes: 9f4a8a2d7f9d ("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>
2018-06-18fsi: scom: Major overhaulBenjamin Herrenschmidt1-30/+394
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>
2018-06-18fsi: scom: Add register definitionsBenjamin Herrenschmidt1-1/+18
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>
2018-06-18fsi: scom: Fixup endian annotationsBenjamin Herrenschmidt1-5/+4
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>
2018-06-18fsi: scom: Whitespace fixesBenjamin Herrenschmidt1-4/+4
No functional changes Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18fsi: scom: Add mutex around FSI2PIB accessesBenjamin Herrenschmidt1-7/+18
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>
2018-06-18fsi: core: Fix sparse warningsJoel Stanley1-10/+13
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>
2018-06-18fsi: master-hub: Fix sparse warningsJoel Stanley1-2/+3
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>
2018-06-18fsi: sbefifo: Fix sparse warningsJoel Stanley1-2/+3
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>
2018-06-14fsi: sbefifo: Remove unneeded semicolonBenjamin Herrenschmidt1-1/+1
Spotted by kbuild-test-bot Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-06-12fsi/sbefifo: Add driver for the SBE FIFOBenjamin Herrenschmidt3-0/+1013
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> ---
2018-06-12fsi: scom: Remove PIB reset during probeEddie James1-8/+0
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>
2018-06-12fsi/master-gpio: Replace bit_bit lock with IRQ disable/enableJeremy Kerr1-25/+23
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>
2018-06-12fsi/fsi-master-gpio: More error handling cleanupBenjamin Herrenschmidt1-21/+5
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>
2018-06-12fsi/fsi-master-gpio: Implement CRC error recoveryBenjamin Herrenschmidt1-18/+72
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.
2018-06-12fsi/gpio: Use relative-addressing commandsJeremy Kerr1-11/+91
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>
2018-06-12fsi/gpio: Include command build in locked sectionJeremy Kerr1-7/+18
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>
2018-06-12fsi/fsi-master-gpio: Delay sampling of FSI data inputBenjamin Herrenschmidt1-0/+5
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>
2018-06-12fsi/fsi-master-gpio: Reduce dpoll clocksBenjamin Herrenschmidt1-2/+3
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>
2018-06-12fsi/fsi-master-gpio: Reduce turnaround clocksBenjamin Herrenschmidt1-1/+1
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>
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