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e09db3d241
linux_dsm_epyc7002/drivers/i2c/busses
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Hans de Goede e09db3d241 x86: baytrail/cherrytrail: Rework and move P-Unit PMIC bus semaphore code 
On some BYT/CHT systems the SoC's P-Unit shares the I2C bus with the
kernel. The P-Unit has a semaphore for the PMIC bus which we can take to
block it from accessing the shared bus while the kernel wants to access it.

Currently we have the I2C-controller driver acquiring and releasing the
semaphore around each I2C transfer. There are 2 problems with this:

1) PMIC accesses often come in the form of a read-modify-write on one of
the PMIC registers, we currently release the P-Unit's PMIC bus semaphore
between the read and the write. If the P-Unit modifies the register during
this window?, then we end up overwriting the P-Unit's changes.
I believe that this is mostly an academic problem, but I'm not sure.

2) To safely access the shared I2C bus, we need to do 3 things:
a) Notify the GPU driver that we are starting a window in which it may not
access the P-Unit, since the P-Unit seems to ignore the semaphore for
explicit power-level requests made by the GPU driver
b) Make a pm_qos request to force all CPU cores out of C6/C7 since entering
C6/C7 while we hold the semaphore hangs the SoC
c) Finally take the P-Unit's PMIC bus semaphore
All 3 these steps together are somewhat expensive, so ideally if we have
a bunch of i2c transfers grouped together we only do this once for the
entire group.

Taking the read-modify-write on a PMIC register as example then ideally we
would only do all 3 steps once at the beginning and undo all 3 steps once
at the end.

For this we need to be able to take the semaphore from within e.g. the PMIC
opregion driver, yet we do not want to remove the taking of the semaphore
from the I2C-controller driver, as that is still necessary to protect many
other code-paths leading to accessing the shared I2C bus.

This means that we first have the PMIC driver acquire the semaphore and
then have the I2C controller driver trying to acquire it again.

To make this possible this commit does the following:

1) Move the semaphore code from being private to the I2C controller driver
into the generic iosf_mbi code, which already has other code to deal with
the shared bus so that it can be accessed outside of the I2C bus driver.

2) Rework the code so that it can be called multiple times nested, while
still blocking I2C accesses while e.g. the GPU driver has indicated the
P-Unit needs the bus through a iosf_mbi_punit_acquire() call.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-25 16:59:08 +02:00
..
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: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-ali1563.c i2c: ali1563: fix checkpatch.pl issues 2014-05-22 10:09:21 +02:00
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: Add an explicit type casting for *get_clk_reg_val 2018-08-04 23:12:31 +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: busses: make use of i2c_8bit_addr_from_msg 2018-05-29 20:30:49 +02:00
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: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
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 x86: baytrail/cherrytrail: Rework and move P-Unit PMIC bus semaphore code 2018-10-25 16:59:08 +02:00
i2c-designware-common.c i2c: designware: Add SPDX license tag 2018-08-20 10:45:45 +02:00
i2c-designware-core.h i2c: designware: Add SPDX license tag 2018-08-20 10:45:45 +02:00
i2c-designware-master.c i2c: designware: Call i2c_dw_clk_rate() only when calculating timings 2018-10-05 13:40:05 +02:00
i2c-designware-pcidrv.c i2c: designware: Add SPDX license tag 2018-08-20 10:45:45 +02:00
i2c-designware-platdrv.c i2c: designware: Re-init controllers with pm_disabled set on resume 2018-08-30 23:02:13 +02:00
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: remove FSF address 2014-11-07 18:35:33 +01:00
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: remove FSF address 2014-11-07 18:35:33 +01:00
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 of_device_get_match_data() 2018-04-30 10:39:28 +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-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: move header to platform_data 2018-05-17 16:27:58 +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: busses: make i2c_adapter_quirks const 2017-08-29 22:32:47 +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: i2c-qcom-geni: Properly handle DMA safe buffers 2018-09-25 00:11:52 +02:00
i2c-qup.c Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-06-14 16:21:46 +09:00
i2c-rcar.c i2c: rcar: cleanup DMA for all kinds of failure 2018-10-20 15:25:59 +02:00
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: fix leak when using DMA bounce buffer 2018-08-30 23:13:59 +02:00
i2c-sibyte.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
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: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-sis630.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
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 fence-post error in retry loop 2018-05-17 15:40:33 +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 Linux 4.18-rc5 2018-07-17 10:03:42 +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: issue STOP only for last message or I2C_M_STOP 2018-09-02 23:50:43 +02:00
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: remove FSF address 2014-11-07 18:35:33 +01:00
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: always use the same device when printing errors 2017-06-27 23:21:00 +02:00
Kconfig i2c: Add Actions Semiconductor Owl family S900 I2C driver 2018-08-04 22:56:02 +02:00
Makefile i2c: Add Actions Semiconductor Owl family S900 I2C driver 2018-08-04 22:56:02 +02:00
scx200_acb.c Annotate hardware config module parameters in drivers/i2c/ 2017-04-20 12:02:32 +01:00