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d60ece5f01
linux/drivers/i2c/busses
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Felipe Balbi d60ece5f01 i2c: omap: ensure writes to dev->buf_len are ordered 
if we allow compiler reorder our writes, we could
fall into a situation where dev->buf_len is reset
for no apparent reason.

This bug was found with a simple script which would
transfer data to an i2c client from 1 to 1024 bytes
(a simple for loop), when we got to transfer sizes
bigger than the fifo size, dev->buf_len was reset
to zero before we had an oportunity to handle XDR
Interrupt. Because dev->buf_len was zero, we entered
omap_i2c_transmit_data() to transfer zero bytes,
which would mean we would just silently exit
omap_i2c_transmit_data() without actually writing
anything to DATA register. That would cause XDR
IRQ to trigger forever and we would never transfer
the remaining bytes.

After adding the memory barrier, we also drop resetting
dev->buf_len to zero in omap_i2c_xfer_msg() because
both omap_i2c_transmit_data() and omap_i2c_receive_data()
will act until dev->buf_len reaches zero, rendering the
other write in omap_i2c_xfer_msg() redundant.

This patch has been tested with pandaboard for a few
iterations of the script mentioned above.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-11-14 17:44:37 +01:00
..
i2c-acorn.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
i2c-ali15x3.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-ali1535.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-ali1563.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-amd756-s4882.c
i2c-amd756.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-amd8111.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-at91.c i2c: at91: fix SMBus quick command 2012-11-14 10:28:28 +01:00
i2c-au1550.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-bfin-twi.c i2c: i2c-bfin-twi: Move blackfin TWI register access Macro to head file. 2012-07-13 08:37:31 +02:00
i2c-cpm.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-davinci.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-designware-core.c i2c-designware: i2c_dw_xfer_msg can be static 2012-10-05 22:23:53 +02:00
i2c-designware-core.h i2c: designware: Add support for 16bit register access 2012-05-12 14:28:11 +02:00
i2c-designware-pcidrv.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-designware-platdrv.c i2c: designware: Add clk_{un}prepare() support 2012-05-12 14:28:15 +02:00
i2c-diolan-u2c.c i2c: diolan-u2c: Fix master_xfer return code 2012-08-18 12:27:27 +02:00
i2c-eg20t.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-elektor.c Fix common misspellings 2011-03-31 11:26:23 -03:00
i2c-gpio.c i2c: i2c-gpio: fix name issue with multiple i2c gpio nodes 2012-11-14 09:56:43 +01:00
i2c-highlander.c Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-01-14 12:32:16 -08:00
i2c-hydra.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-i801.c i2c-i801: Fix comment 2012-10-28 21:37:01 +01:00
i2c-ibm_iic.c Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-01-14 12:32:16 -08:00
i2c-ibm_iic.h
i2c-imx.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-intel-mid.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-iop3xx.c i2c: iop3xx: use standard gpiolib functions 2012-07-25 09:26:41 -05:00
i2c-iop3xx.h i2c-iop3xx: add iomem annotation 2011-01-04 00:53:37 +00:00
i2c-isch.c i2c-isch: Decrease delay in command completion check loop 2012-03-26 21:47:18 +02:00
i2c-mpc.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-mv64xxx.c I2C: MV64XYZ: Add Device Tree support 2012-07-23 22:04:11 +02:00
i2c-mxs.c i2c: mxs: remove broken PIOQUEUE support 2012-11-02 10:52:32 +01:00
i2c-nforce2-s4985.c
i2c-nforce2.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-nomadik.c i2c: nomadik: Fix the usage of wait_for_completion_timeout 2012-11-12 18:21:55 +01:00
i2c-nuc900.c ARM: w90x900: move platform_data definitions 2012-09-14 11:18:59 +02:00
i2c-ocores.c i2c: ocores: Use devm_request_and_ioremap() 2012-11-13 12:16:24 +01:00
i2c-octeon.c i2c: Convert i2c-octeon.c to use device tree. 2012-07-23 13:54:53 +01:00
i2c-omap.c i2c: omap: ensure writes to dev->buf_len are ordered 2012-11-14 17:44:37 +01:00
i2c-parport-light.c i2c-parport: Various cleanups 2011-05-24 20:58:49 +02:00
i2c-parport.c i2c-parport: i2c_parport_irq can be static 2012-10-05 22:23:53 +02:00
i2c-parport.h i2c-parport: Various cleanups 2011-05-24 20:58:49 +02:00
i2c-pasemi.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-pca-isa.c i2c-pca: Fix waitforcompletion() return value 2010-09-30 14:14:22 +02:00
i2c-pca-platform.c i2c: Dynamically assign adapter id if it wasn't explictly specified 2012-05-12 14:28:11 +02:00
i2c-piix4.c i2c-piix4: Fix build failure 2012-10-05 22:23:55 +02:00
i2c-pmcmsp.c i2c-pmcmsp: remove IRQF_SAMPLE_RANDOM which is now a no-op 2012-07-19 10:38:47 -04:00
i2c-pnx.c i2c: pnx: Fix read transactions of >= 2 bytes 2012-09-12 17:52:44 +02:00
i2c-powermac.c i2c/powermac: Improve detection of devices from device-tree 2012-07-11 18:22:46 +10:00
i2c-puv3.c i2c-puv3: Use struct dev_pm_ops for power management 2012-07-12 12:04:54 +02:00
i2c-pxa-pci.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-pxa.c i2c/i2c-pxa: remove conditional compilation of clk code 2012-07-30 17:25:12 -07:00
i2c-rcar.c i2c: rcar: fix section mismatch 2012-11-13 11:24:15 +01:00
i2c-s3c2410.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-s6000.c i2c: Change mail address of Oskar Schirmer 2012-05-17 15:15:56 +02:00
i2c-s6000.h i2c: Change mail address of Oskar Schirmer 2012-05-17 15:15:56 +02:00
i2c-scmi.c i2c-scmi: convert to module_acpi_driver() 2012-09-21 13:39:56 -04:00
i2c-sh7760.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-sh_mobile.c i2c: sh_mobile: add device tree support 2012-05-12 14:28:12 +02:00
i2c-sibyte.c i2c/mips: Fix error return codes from Sibyte i2c bus driver 2010-07-10 09:42:47 +02:00
i2c-simtec.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-sirf.c i2c: add CSR SiRFprimaII on-chip I2C controllers driver 2012-03-07 19:05:04 +01:00
i2c-sis96x.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-sis630.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-sis5595.c i2c: Convert to DEFINE_PCI_DEVICE_TABLE 2012-01-12 20:32:04 +01:00
i2c-stu300.c i2c: stu300: use devm managed resources 2012-07-16 13:48:51 +02:00
i2c-taos-evm.c i2c-taos-evm: Fix log messages 2011-06-29 11:36:10 +02:00
i2c-tegra.c i2c: tegra: set irq name as device name 2012-11-02 10:52:52 +01:00
i2c-tiny-usb.c i2c-tiny-usb: Add support for the Robofuzz OSIF USB/I2C converter 2012-07-24 14:13:59 +02:00
i2c-versatile.c i2c: Dynamically assign adapter id if it wasn't explictly specified 2012-05-12 14:28:11 +02:00
i2c-via.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-viapro.c i2c-viapro: Add VIA VX900 device ID 2012-10-05 22:23:53 +02:00
i2c-xiic.c I2C: xiic: Add OF binding support 2012-05-12 14:28:18 +02:00
i2c-xlr.c i2c: Support for Netlogic XLR/XLS I2C controller. 2012-02-24 22:25:57 +01:00
Kconfig i2c-i801: Simplify dependency towards GPIOLIB 2012-10-28 21:37:01 +01:00
Makefile i2c-stub: Move to drivers/i2c 2012-10-28 21:37:00 +01:00
scx200_acb.c i2c/scx200_*: Replace printks with pr_<level>s 2012-10-05 22:23:52 +02:00
scx200_i2c.c i2c/scx200_*: Replace printks with pr_<level>s 2012-10-05 22:23:52 +02:00