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6c7f25cae5
linux/drivers/i2c/busses
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Adamski, Krzysztof (Nokia - PL/Wroclaw) 6c7f25cae5 i2c: axxia: properly handle master timeout 
According to Intel (R) Axxia TM Lionfish Communication Processor
Peripheral Subsystem Hardware Reference Manual, the AXXIA I2C module
have a programmable Master Wait Timer, which among others, checks the
time between commands send in manual mode. When a timeout (25ms) passes,
TSS bit is set in Master Interrupt Status register and a Stop command is
issued by the hardware.

The axxia_i2c_xfer(), does not properly handle this situation, however.
For each message a separate axxia_i2c_xfer_msg() is called and this
function incorrectly assumes that any interrupt might happen only when
waiting for completion. This is mostly correct but there is one
exception - a master timeout can trigger if enough time has passed
between individual transfers. It will, by definition, happen between
transfers when the interrupts are disabled by the code. If that happens,
the hardware issues Stop command.

The interrupt indicating timeout will not be triggered as soon as we
enable them since the Master Interrupt Status is cleared when master
mode is entered again (which happens before enabling irqs) meaning this
error is lost and the transfer is continued even though the Stop was
issued on the bus. The subsequent operations completes without error but
a bogus value (0xFF in case of read) is read as the client device is
confused because aborted transfer. No error is returned from
master_xfer() making caller believe that a valid value was read.

To fix the problem, the TSS bit (indicating timeout) in Master Interrupt
Status register is checked before each transfer. If it is set, there was
a timeout before this transfer and (as described above) the hardware
already issued Stop command so the transaction should be aborted thus
-ETIMEOUT is returned from the master_xfer() callback. In order to be
sure no timeout was issued we can't just read the status just before
starting new transaction as there will always be a small window of time
(few CPU cycles at best) where this might still happen. For this reason
we have to temporally disable the timer before checking for TSS bit.
Disabling it will, however, clear the TSS bit so in order to preserve
that information, we have to read it in ISR so we have to ensure that
the TSS interrupt is not masked between transfers of one transaction.
There is no need to call bus recovery or controller reinitialization if
that happens so it's skipped.

Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-12-06 23:14:53 +01:00
..
i2c-acorn.c i2c: acorn: remove outdated path from file header 2018-01-18 00:08:20 +01:00
i2c-ali15x3.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00
i2c-ali1535.c
i2c-ali1563.c
i2c-altera.c i2c: altera: Add Altera I2C Controller driver 2017-09-13 23:37:16 +02:00
i2c-amd756-s4882.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
i2c-amd756.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-amd8111.c i2c: amd8111: Mark expected switch fall-through 2018-08-08 22:28:46 +02:00
i2c-aspeed.c i2c: aspeed: fix invalid clock parameters for very large divisors 2018-09-24 23:50:42 +02:00
i2c-at91.c i2c: at91: Read all available bytes at once 2018-04-30 10:39:28 +02:00
i2c-au1550.c i2c: au1550: Convert to devm_kzalloc and devm_ioremap_resource 2015-10-23 23:31:11 +02:00
i2c-axxia.c i2c: axxia: properly handle master timeout 2018-12-06 23:14:53 +01:00
i2c-bcm2835.c i2c: bcm2835: Set up the rising/falling edge delays 2018-02-22 12:11:07 +01:00
i2c-bcm-iproc.c i2c: use dev_get_drvdata() to get private data in suspend/resume hooks 2017-07-31 17:03:32 +02:00
i2c-bcm-kona.c Merge branch 'i2c/for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-10-07 14:12:21 -07:00
i2c-brcmstb.c i2c: remove i2c_lock_adapter and use i2c_lock_bus directly 2018-07-13 00:09:37 +02:00
i2c-cadence.c i2c: use dev_get_drvdata() to get private data in suspend/resume hooks 2017-07-31 17:03:32 +02:00
i2c-cbus-gpio.c
i2c-cht-wc.c i2c-cht-wc: Fix bq24190 supplier 2018-07-02 17:38:07 +02:00
i2c-cpm.c i2c: busses: make i2c_adapter_quirks const 2017-08-29 22:32:47 +02:00
i2c-cros-ec-tunnel.c i2c: i2c-cros-ec-tunnel: Reduce logging noise 2017-01-28 22:16:38 +01:00
i2c-davinci.c Merge branch 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-08-21 17:40:46 -07:00
i2c-designware-baytrail.c More ACPI updates for 4.20-rc1 2018-10-30 09:15:31 -07:00
i2c-designware-common.c More ACPI updates for 4.20-rc1 2018-10-30 09:15:31 -07:00
i2c-designware-core.h More ACPI updates for 4.20-rc1 2018-10-30 09:15:31 -07:00
i2c-designware-master.c This is the 4.19-rc7 release 2018-10-11 23:07:30 +02:00
i2c-designware-pcidrv.c i2c: designware: Add SPDX license tag 2018-08-20 10:45:45 +02:00
i2c-designware-platdrv.c More ACPI updates for 4.20-rc1 2018-10-30 09:15:31 -07:00
i2c-designware-slave.c i2c: designware: Add SPDX license tag 2018-08-20 10:45:45 +02:00
i2c-digicolor.c i2c: digicolor: use clk_disable_unprepare instead of clk_unprepare 2016-11-18 01:48:01 +01:00
i2c-diolan-u2c.c i2c: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
i2c-dln2.c i2c: constify i2c_adapter_quirks structures 2016-11-18 02:05:03 +01:00
i2c-efm32.c i2c: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
i2c-eg20t.c i2c: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
i2c-elektor.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00
i2c-emev2.c i2c: use SPDX identifier for Renesas drivers 2018-08-24 14:49:36 +02:00
i2c-exynos5.c i2c: exynos5: Describe the hardware variant for readability 2018-07-21 00:15:22 +02:00
i2c-fsi.c i2c: fsi: Add bus recovery 2018-07-21 00:07:09 +02:00
i2c-gpio.c Merge branch 'i2c/precise-locking-names_immutable' into i2c/for-4.19 2018-07-13 00:12:53 +02:00
i2c-highlander.c i2c: use SPDX identifier for Renesas drivers 2018-08-24 14:49:36 +02:00
i2c-hix5hd2.c i2c: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
i2c-hydra.c
i2c-i801.c i2c: i801: fix DNV's SMBCTRL register offset 2018-09-04 18:04:55 +02:00
i2c-ibm_iic.c i2c: ibm_iic: don't check number of messages in the driver 2018-05-24 22:05:54 +02:00
i2c-ibm_iic.h
i2c-img-scb.c i2c: img-scb: Add runtime PM 2017-10-28 14:03:45 +02:00
i2c-imx-lpi2c.c i2c: imx-lpi2c: Remove mx8dv compatible entry 2018-09-02 23:50:43 +02:00
i2c-imx.c Merge branch 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-08-21 17:40:46 -07:00
i2c-iop3xx.c i2c: iop3xx: use new 8 bit address helper function 2016-04-11 18:54:59 +02:00
i2c-iop3xx.h
i2c-isch.c i2c: i2c-isch: fix spelling mistake "unitialized" -> "uninitialized" 2018-09-25 00:14:04 +02:00
i2c-ismt.c i2c: ismt: 16-byte align the DMA buffer address 2018-01-15 21:02:43 +01:00
i2c-jz4780.c i2c: jz4780: Fix module autoload 2016-10-25 11:48:58 +02:00
i2c-kempld.c i2c: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
i2c-lpc2k.c i2c: use dev_get_drvdata() to get private data in suspend/resume hooks 2017-07-31 17:03:32 +02:00
i2c-meson.c i2c: meson: update doc description to fix build warnings 2018-01-26 18:33:44 +01:00
i2c-mlxcpld.c i2c: mlxcpld: Allow configurable adapter id for mlxcpld 2018-04-30 10:39:29 +02:00
i2c-mpc.c i2c: mpc: always determine I2C clock prescaler at runtime 2018-01-15 19:19:55 +01:00
i2c-mt65xx.c i2c: mediatek: Use DMA safe buffers for i2c transactions 2018-09-06 20:33:15 +02:00
i2c-mv64xxx.c i2c: mv64xxx: Apply errata delay only in standard mode 2018-03-17 21:20:04 +01:00
i2c-mxs.c i2c: mxs: use core to detect 'no zero length' quirk 2018-08-04 23:25:06 +02:00
i2c-nforce2-s4985.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
i2c-nforce2.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
i2c-nomadik.c i2c: busses: remove superfluous ignoring of children for RPM 2018-05-08 23:19:02 +02:00
i2c-nvidia-gpu.c i2c: nvidia-gpu: limit reads also for combined messages 2018-11-27 14:00:22 +01:00
i2c-ocores.c i2c: ocores: update my email address 2018-08-24 14:46:43 +02:00
i2c-octeon-core.c i2c: octeon: Prevent error message on bus error 2018-03-02 11:11:15 +01:00
i2c-octeon-core.h i2c: octeon: Prevent error message on bus error 2018-03-02 11:11:15 +01:00
i2c-octeon-platdrv.c i2c: busses: make i2c_adapter const 2017-08-29 22:26:08 +02:00
i2c-omap.c i2c: omap: use core to detect 'no zero length' quirk 2018-10-05 18:04:50 +02:00
i2c-opal.c i2c: opal: don't check number of messages in the driver 2018-05-24 22:06:17 +02:00
i2c-owl.c i2c: Add Actions Semiconductor Owl family S900 I2C driver 2018-08-04 22:56:02 +02:00
i2c-parport-light.c i2c: i2c-smbus: Use threaded irq for smbalert 2017-10-28 23:42:26 +02:00
i2c-parport.c i2c: i2c-smbus: Use threaded irq for smbalert 2017-10-28 23:42:26 +02:00
i2c-parport.h i2c: parport: Add VCT-jig adapter 2015-08-10 08:37:34 +02:00
i2c-pasemi.c i2c: pasemi: remove hardcoded bus numbers on smbus 2018-08-20 11:01:13 +02:00
i2c-pca-isa.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00
i2c-pca-platform.c i2c: pca-platform: move header to platform_data 2018-05-17 16:27:58 +02:00
i2c-piix4.c i2c: piix4: Use request_muxed_region 2018-03-02 11:17:23 +01:00
i2c-pmcmsp.c i2c: pmcmsp: use core to detect 'no zero length' quirk 2018-08-04 23:25:06 +02:00
i2c-pnx.c i2c: pnx: move header into the driver 2018-05-17 16:27:59 +02:00
i2c-powermac.c i2c: Convert to using %pOFn instead of device_node.name 2018-10-05 14:10:40 +02:00
i2c-puv3.c i2c: busses: make i2c_algorithm const 2017-08-29 22:20:20 +02:00
i2c-pxa-pci.c ARM: pxa: move header file out of I2C realm 2017-11-28 22:49:30 +01:00
i2c-pxa.c ARM: pxa: move header file out of I2C realm 2017-11-28 22:49:30 +01:00
i2c-qcom-geni.c i2c: qcom-geni: Fix runtime PM mismatch with child devices 2018-11-09 17:25:48 +01:00
i2c-qup.c i2c: qup: use core to detect 'no zero length' quirk 2018-10-05 18:05:08 +02:00
i2c-rcar.c i2c: rcar: check bus state before reinitializing 2018-11-27 14:00:36 +01:00
i2c-riic.c i2c: use SPDX identifier for Renesas drivers 2018-08-24 14:49:36 +02:00
i2c-rk3x.c i2c: rk3x: Don't print visible virtual mapping MMIO address 2018-05-24 22:09:05 +02:00
i2c-robotfuzz-osif.c i2c: robotfuzz-osif: drop pointless test 2018-05-24 22:13:04 +02:00
i2c-s3c2410.c i2c: remove i2c_lock_adapter and use i2c_lock_bus directly 2018-07-13 00:09:37 +02:00
i2c-scmi.c i2c: i2c-scmi: fix for i2c_smbus_write_block_data 2018-10-01 01:04:07 +02:00
i2c-sh7760.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-sh_mobile.c i2c: sh_mobile: Remove dummy runtime PM callbacks 2018-10-29 18:53:38 +00:00
i2c-sibyte.c
i2c-simtec.c i2c: simtec: use release_mem_region instead of release_resource 2017-08-14 21:39:21 +02:00
i2c-sirf.c i2c: busses: i2c-sirf: Fix spelling: "formular" -> "formula". 2018-02-22 12:12:35 +01:00
i2c-sis96x.c
i2c-sis630.c
i2c-sis5595.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00
i2c-sprd.c i2c: remove i2c_lock_adapter and use i2c_lock_bus directly 2018-07-13 00:09:37 +02:00
i2c-st.c i2c: use dev_get_drvdata() to get private data in suspend/resume hooks 2017-07-31 17:03:32 +02:00
i2c-stm32.c i2c: i2c-stm32: Add generic DMA API 2018-04-30 10:39:27 +02:00
i2c-stm32.h i2c: i2c-stm32: Add generic DMA API 2018-04-30 10:39:27 +02:00
i2c-stm32f4.c i2c-stm32f4: remove redundant initialization of pointer reg 2018-02-27 13:51:05 +01:00
i2c-stm32f7.c i2c: stm32f7: fix documentation typo 2018-05-17 15:59:02 +02:00
i2c-stu300.c i2c: stu300: use core to detect 'no zero length' quirk 2018-08-04 23:25:07 +02:00
i2c-sun6i-p2wi.c i2c: sun6i-pw2i: explicitly request exclusive reset control 2017-08-14 21:40:21 +02:00
i2c-synquacer.c i2c: synquacer: fix fall-through annotation 2018-09-25 00:06:02 +02:00
i2c-taos-evm.c i2c: taos-evm: Remove duplicate NULL check 2017-11-02 00:01:21 +01:00
i2c-tegra-bpmp.c i2c: tegra: fix spelling mistake: "contoller" -> "controller" 2017-04-21 14:04:57 +02:00
i2c-tegra.c i2c: tegra: use core to detect 'no zero length' quirk 2018-10-05 18:05:27 +02:00
i2c-thunderx-pcidrv.c i2c: thunderx: Remove duplicate NULL check 2017-11-02 00:01:31 +01:00
i2c-tiny-usb.c i2c: i2c-tiny-usb: fix buffer not being DMA capable 2017-05-22 10:33:42 +02:00
i2c-uniphier-f.c i2c: uniphier-f: fix race condition when IRQ is cleared 2018-10-29 18:53:37 +00:00
i2c-uniphier.c i2c: uniphier: issue STOP only for last message or I2C_M_STOP 2018-09-02 23:50:43 +02:00
i2c-versatile.c i2c: versatile: Make i2c_algo_bit_data const 2017-08-29 22:34:12 +02:00
i2c-via.c
i2c-viapro.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00
i2c-viperboard.c i2c: viperboard: return message count on master_xfer success 2018-05-15 09:31:26 +02:00
i2c-wmt.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-xgene-slimpro.c i2c: xgene-slimpro: Support v2 2017-11-01 23:54:53 +01:00
i2c-xiic.c i2c: xiic: Make the start and the byte count write atomic 2018-09-06 20:49:09 +02:00
i2c-xlp9xx.c i2c: xlp9xx: Fix case where SSIF read transaction completes early 2018-08-09 17:41:13 +02:00
i2c-xlr.c i2c: xlr: use core to detect 'no zero length' quirk 2018-08-04 23:25:08 +02:00
i2c-zx2967.c i2c: zx2967: use core to detect 'no zero length' quirk 2018-10-05 18:05:37 +02:00
Kconfig i2c: add i2c bus driver for NVIDIA GPU 2018-11-09 17:46:43 +01:00
Makefile i2c: add i2c bus driver for NVIDIA GPU 2018-11-09 17:46:43 +01:00
scx200_acb.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00