From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH V12 3/5] i2c: tegra: Add DMA support Date: Wed, 6 Feb 2019 17:35:15 +0300 Message-ID: <2f6ac9c6-bdc8-2a48-8f95-d761d5d56d8d@gmail.com> References: <1549406769-27544-1-git-send-email-skomatineni@nvidia.com> <1549406769-27544-3-git-send-email-skomatineni@nvidia.com> <85b77477-3175-0501-8753-f39d3b60538e@gmail.com> <20190206130909.GJ21676@ulmo> <20190206131310.GK21676@ulmo> <6edef92d-66a7-0f70-e59e-7381b82516eb@gmail.com> <20190206140141.GO21676@ulmo> <9b4bfee0-f3f2-bae7-5010-97a86bb5e03f@gmail.com> <649cdfb4-214e-bf01-348d-f950628ecf9b@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Sowjanya Komatineni , Thierry Reding Cc: Jonathan Hunter , Mantravadi Karthik , Shardar Mohammed , Timo Alho , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" List-Id: linux-i2c@vger.kernel.org 06.02.2019 17:29, Sowjanya Komatineni пишет: > >>>>>> Yes please post full log of PIO only and DMA only Also, in above >>>>>> log, lots of DMA transfer went thru fine except this one transfer >>>>>> where DMA timed out. >>>>>> DMA completion doesnt happen on DMA submit during this particular >>>>>> transaction timeframe for some reason. >>>>> >>>>> Dmitry, can you provide some background information on the setup >>>>> that you're using? I vaguely remember something about i2c@7000d000 >>>>> being special on older Tegra devices. Perhaps there's something >>>>> additional that we need to take into account? >>>>> >>>>> Aha! Look at tegra_i2c_reg_addr() which special-cases I2C_TX_FIFO on >>>>> the DVC variant of the controller, which is exactly the one that you >>>>> are seeing the timeouts on and it's exactly the register that we use >>>>> as destination for the DMA transfer. >>>>> >>>>> I think we need to do something like this: >>>>> >>>>> slv_config.dst_addr = i2c_dev->base_phys + >>>>> tegra_i2c_reg_addr(i2c_dev, I2C_TX_FIFO); >>>>> >>>>> to make sure we pass the right FIFO register address to DMA. >>>> >>>> I'm running it on T20 at the moment. I don't know about the DVC quirks, but sounds plausible. Please let me know if you need any other info. >>>> >>>> Here the full logs: >>>> >>>> PIO-only: http://dpaste.com/2MX3EAN.txt >>>> DMA-only: http://dpaste.com/3VXZSSM.txt >>>> >>>> Note the "Failed to read T44 and T5 (-110)" error that happens in DMA-only. And it happens on i2c@7000c000, DVC is i2c@7000d000. >>> >>> Yes this is due to same issue theirry mentioned. >>> Prior to transfer timeout for touch, tps6586x regulator probe failed due to i2c timeout which uses DVC (7000D000) and since DMA mode is enforced all DVC/PWR I2C transactions also go thru DMA and FIFO register for DVC offset is not accounted when configure to dma slave. >>> Will fix and send so you can see for repro with updated patch.. >>> >>> >>> [ 0.925155] tegra-i2c 7000d000.i2c: starting DMA for length: 16 >>> [ 0.925165] tegra-i2c 7000d000.i2c: unmasked irq: 0c >>> [ 1.028961] tegra-i2c 7000d000.i2c: i2c transfer timed out >>> [ 1.028968] tegra-i2c 7000c000.i2c: DMA transfer timeout >>> [ 1.028995] tps6586x 3-0034: Chip ID read failed: -110 >>> [ 1.029029] tps6586x: probe of 3-0034 failed with error -5 >>> [ 1.029045] atmel_mxt_ts 0-004c: __mxt_read_reg: i2c transfer failed (-110) >>> [ 1.029051] atmel_mxt_ts 0-004c: Failed to read T44 and T5 (-110) >>> >> >> I think tps6586x and atmel-touch should be independent issues, but will see. Thanks! > Whats your platform setup? Is atmel touch power ON default or its programmed during boot by SW whcih need to use DVC? > It's "power ON default". I tried to boot in PIO-only mode with tps6586x disabled and there is no "Failed to read T44 and T5" error, atmel probed successfully.