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linux/drivers/i2c/busses
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Russell King 4d6d5f1d08 i2c: designware: fix rx fifo depth tracking 
When loading the TX fifo to receive bytes on the I2C bus, we incorrectly
count the number of bytes:

	rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);

	while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
		if (rx_limit - dev->rx_outstanding <= 0)
			break;
		rx_limit--;
		dev->rx_outstanding++;
	}

DW_IC_RXFLR indicates how many bytes are available to be read in the
FIFO, dev->rx_fifo_depth is the FIFO size, and dev->rx_outstanding is
the number of bytes that we've requested to be read so far, but which
have not been read.

Firstly, increasing dev->rx_outstanding and decreasing rx_limit and then
comparing them results in each byte consuming "two" bytes in this
tracking, so this is obviously wrong.

Secondly, the number of bytes that _could_ be received into the FIFO at
any time is the number of bytes we have so far requested but not yet
read from the FIFO - in other words dev->rx_outstanding.

So, in order to request enough bytes to fill the RX FIFO, we need to
request dev->rx_fifo_depth - dev->rx_outstanding bytes.

Modifying the code thusly results in us reaching the maximum number of
bytes outstanding each time we queue more "receive" operations, provided
the transfer allows that to happen.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
 		2016-11-24 16:18:15 +01:00
..
Kconfig i2c: allow configuration of imx driver for ColdFire architecture 2016-10-25 11:48:57 +02:00
Makefile i2c: thunderx: Add i2c driver for ThunderX SOC 2016-08-26 00:41:55 +02:00
i2c-acorn.c i2c: acorn: is tristate and should use module.h 2014-01-24 18:21:11 +01:00
i2c-ali15x3.c i2c: remove FSF address 2014-11-07 18:35:33 +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-amd756-s4882.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-amd756.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-amd8111.c i2c: remove DEFINE_PCI_DEVICE_TABLE macro 2014-03-13 09:44:59 +01:00
i2c-at91.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +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: disable clks in case of failure in probe 2016-09-24 11:26:55 +02:00
i2c-bcm-iproc.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +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-bcm2835.c i2c: bcm2835: Don't complain on -EPROBE_DEFER from getting our clock 2016-07-22 09:23:53 +02:00
i2c-bfin-twi.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-brcmstb.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-cadence.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-cbus-gpio.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-cpm.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-cros-ec-tunnel.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-davinci.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-designware-baytrail.c i2c: designware-platform: Drop duplicate module information 2016-02-12 20:40:13 +01:00
i2c-designware-core.c i2c: designware: fix rx fifo depth tracking 2016-11-24 16:18:15 +01:00
i2c-designware-core.h i2c: designware: detect when dynamic tar update is possible 2016-08-26 00:42:15 +02:00
i2c-designware-pcidrv.c i2c: designware-pci: clarify a comment for Merrifield 2016-07-06 00:42:17 +09:00
i2c-designware-platdrv.c i2c: designware: Find bus speed from ACPI 2016-08-26 00:42:11 +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: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-dln2.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-efm32.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-eg20t.c i2c-eg20t: fix race between i2c init and interrupt enable 2016-09-21 18:07:51 +02:00
i2c-elektor.c i2c: elektor: Utilize the module_isa_driver macro 2016-06-19 19:45:43 +02:00
i2c-emev2.c i2c: emev2: add slave support 2015-12-05 19:55:36 +01:00
i2c-exynos5.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-gpio.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-highlander.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-hix5hd2.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-hydra.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-i801.c i2c: i801: Fix I2C Block Read on 8-Series/C220 and later 2016-10-25 12:00:01 +02:00
i2c-ibm_iic.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-ibm_iic.h
…
i2c-img-scb.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-imx.c i2c: imx: defer probe if bus recovery GPIOs are not ready 2016-10-25 12:15:00 +02:00
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: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-ismt.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-jz4780.c i2c: jz4780: Fix module autoload 2016-10-25 11:48:58 +02:00
i2c-kempld.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-lpc2k.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-meson.c i2c: meson: add gxbb compatible string 2016-09-15 21:37:16 +02:00
i2c-mpc.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-mt65xx.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-mv64xxx.c i2c: mv64xxx: remove CONFIG_HAVE_CLK conditionals 2016-04-27 19:03:15 +02:00
i2c-mxs.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-nforce2-s4985.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-nforce2.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-nomadik.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-ocores.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-octeon-core.c i2c: octeon: thunderx: Limit register access retries 2016-09-24 11:22:24 +02:00
i2c-octeon-core.h i2c: octeon: thunderx: Limit register access retries 2016-09-24 11:22:24 +02:00
i2c-octeon-platdrv.c i2c: octeon: Sort include files alphabetically 2016-08-26 00:41:58 +02:00
i2c-omap.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-opal.c powerpc/opal: Add inline function to get rc from an ASYNC_COMP opal_msg 2016-06-29 17:33:18 +10:00
i2c-parport-light.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
i2c-parport.c i2c: parport: start using pr_fmt 2015-08-10 08:37:28 +02:00
i2c-parport.h i2c: parport: Add VCT-jig adapter 2015-08-10 08:37:34 +02:00
i2c-pasemi.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-pca-isa.c i2c: pca-isa: Utilize the module_isa_driver macro 2016-06-19 19:49:29 +02:00
i2c-pca-platform.c i2c: pca-platform: fix broken email address 2015-04-23 19:35:30 +02:00
i2c-piix4.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-pmcmsp.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-pnx.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-powermac.c i2c: powermac: use new 8 bit address helper function 2016-04-11 18:54:59 +02:00
i2c-puv3.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-pxa-pci.c i2c: remove DEFINE_PCI_DEVICE_TABLE macro 2014-03-13 09:44:59 +01:00
i2c-pxa.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-qup.c i2c: qup: skip qup_i2c_suspend if the device is already runtime suspended 2016-09-22 20:11:14 +02:00
i2c-rcar.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-riic.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-rk3x.c i2c: rk3x: Give the tuning value 0 during rk3x_i2c_v0_calc_timings 2016-10-25 11:11:46 +02:00
i2c-robotfuzz-osif.c i2c: robotfuzz-osif: Constify osif_table 2016-06-13 22:32:09 +02:00
i2c-s3c2410.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-scmi.c i2c: delete non-required instances of include <linux/init.h> 2014-01-24 18:24:31 +01:00
i2c-sh7760.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-sh_mobile.c 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-sibyte.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-simtec.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
i2c-sirf.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
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 i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-st.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-stu300.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-sun6i-p2wi.c i2c: busses: drop owner assignment from platform_drivers 2014-10-20 16:20:37 +02:00
i2c-taos-evm.c i2c: taos-evm: replace simple_strtoul by kstrtou8 2015-11-30 18:37:22 +01:00
i2c-tegra.c i2c: tegra: Fix assignment of boolean variables 2016-09-08 22:36:18 +02:00
i2c-thunderx-pcidrv.c i2c: octeon,thunderx: Move register offsets to struct 2016-08-26 00:41:57 +02:00
i2c-tiny-usb.c i2c: i2c-tiny-usb: Remove RobotFuzz USB vendor:product ID 2014-01-13 13:56:52 +01:00
i2c-uniphier-f.c i2c: uniphier-f: fix misdetection of incomplete STOP condition 2016-09-24 11:19:15 +02:00
i2c-uniphier.c i2c: uniphier: avoid WARN_ON() of clk_disable() in failure path 2016-09-08 22:40:32 +02:00
i2c-versatile.c i2c: versatile: Convert to use resource managed devm_* APIs 2016-07-14 21:21:56 +09:00
i2c-via.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-viapro.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-viperboard.c i2c: viperboard: clean up inconsistent indenting 2015-08-10 08:37:38 +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: Avoid dma_buffer overrun 2016-10-25 11:50:52 +02:00
i2c-xiic.c i2c: don't print error when adding adapter fails 2016-08-22 08:19:55 +02:00
i2c-xlp9xx.c i2c: xlp9xx: Fix module autoload 2016-10-25 11:48:59 +02:00
i2c-xlr.c i2c: xlr: Fix module autoload for OF registration 2016-10-25 11:49:00 +02:00
scx200_acb.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00