Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965055AbcJVRrr (ORCPT ); Sat, 22 Oct 2016 13:47:47 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:53853 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964846AbcJVRro (ORCPT ); Sat, 22 Oct 2016 13:47:44 -0400 Subject: Re: [PATCH v3 2/4] drivers: iio: ti_am335x_adc: add dma support To: Mugunthan V N , linux-iio@vger.kernel.org References: <20161005090443.24576-1-mugunthanvnm@ti.com> <20161005090443.24576-3-mugunthanvnm@ti.com> Cc: Tony Lindgren , Rob Herring , Mark Rutland , Russell King , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Lee Jones , Vignesh R , "Andrew F . Davis" , linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sekhar Nori , Peter Ujfalusi , John Syne From: Jonathan Cameron Message-ID: <28c29f63-d7ef-0ef2-7af1-cf6d631136fc@kernel.org> Date: Sat, 22 Oct 2016 18:47:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10278 Lines: 305 On 19/10/16 09:52, Mugunthan V N wrote: > On Sunday 09 October 2016 02:00 PM, Jonathan Cameron wrote: >> On 05/10/16 10:04, Mugunthan V N wrote: >>> This patch adds the required pieces to ti_am335x_adc driver for >>> DMA support >>> >>> Signed-off-by: Mugunthan V N >> Hi, >> >> Just the one question inline. I'll also need an Ack from Lee as >> this touches code in mfd (as does the previous patch). >> We have obviously missed this merge window, so no particular rush. Question answered below. So just need that Ack from Lee. >> >> Otherwise, looking very nice indeed. Got to get my BBB out and play >> with this now ;) >> >> Jonathan >>> --- >>> drivers/iio/adc/ti_am335x_adc.c | 148 ++++++++++++++++++++++++++++++++++- >>> include/linux/mfd/ti_am335x_tscadc.h | 7 ++ >>> 2 files changed, 152 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c >>> index c3cfacca..ad9dec3 100644 >>> --- a/drivers/iio/adc/ti_am335x_adc.c >>> +++ b/drivers/iio/adc/ti_am335x_adc.c >>> @@ -30,10 +30,28 @@ >>> #include >>> #include >>> >>> +#include >>> +#include >>> + >>> +#define DMA_BUFFER_SIZE SZ_2K >>> + >>> +struct tiadc_dma { >>> + struct dma_slave_config conf; >>> + struct dma_chan *chan; >>> + dma_addr_t addr; >>> + dma_cookie_t cookie; >>> + u8 *buf; >>> + int current_period; >>> + int period_size; >>> + u8 fifo_thresh; >>> +}; >>> + >>> struct tiadc_device { >>> struct ti_tscadc_dev *mfd_tscadc; >>> + struct tiadc_dma dma; >>> struct mutex fifo1_lock; /* to protect fifo access */ >>> int channels; >>> + int total_ch_enabled; >>> u8 channel_line[8]; >>> u8 channel_step[8]; >>> int buffer_en_ch_steps; >>> @@ -198,6 +216,67 @@ static irqreturn_t tiadc_worker_h(int irq, void *private) >>> return IRQ_HANDLED; >>> } >>> >>> +static void tiadc_dma_rx_complete(void *param) >>> +{ >>> + struct iio_dev *indio_dev = param; >>> + struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> + u8 *data; >>> + int i; >>> + >>> + data = dma->buf + dma->current_period * dma->period_size; >>> + dma->current_period = 1 - dma->current_period; /* swap the buffer ID */ >>> + >>> + for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) { >>> + iio_push_to_buffers(indio_dev, data); >>> + data += indio_dev->scan_bytes; >>> + } >> Hmm. Another case for the mooted iio_push_to_buffers_multi. Guess >> we should move on with that one ;) >>> +} >>> + >>> +static int tiadc_start_dma(struct iio_dev *indio_dev) >>> +{ >>> + struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> + struct dma_async_tx_descriptor *desc; >>> + >>> + dma->current_period = 0; /* We start to fill period 0 */ >>> + /* >>> + * Make the fifo thresh as the multiple of total number of >>> + * channels enabled, so make sure that cyclic DMA period >>> + * length is also a multiple of total number of channels >>> + * enabled. This ensures that no invalid data is reported >>> + * to the stack via iio_push_to_buffers(). >>> + */ >>> + dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1, >>> + adc_dev->total_ch_enabled) - 1; >>> + /* Make sure that period length is multiple of fifo thresh level */ >>> + dma->period_size = rounddown(DMA_BUFFER_SIZE / 2, >>> + (dma->fifo_thresh + 1) * sizeof(u16)); >>> + >>> + dma->conf.src_maxburst = dma->fifo_thresh + 1; >>> + dmaengine_slave_config(dma->chan, &dma->conf); >>> + >>> + desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr, >>> + dma->period_size * 2, >>> + dma->period_size, DMA_DEV_TO_MEM, >>> + DMA_PREP_INTERRUPT); >>> + if (!desc) >>> + return -EBUSY; >>> + >>> + desc->callback = tiadc_dma_rx_complete; >>> + desc->callback_param = indio_dev; >>> + >>> + dma->cookie = dmaengine_submit(desc); >>> + >>> + dma_async_issue_pending(dma->chan); >>> + >>> + tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh); >>> + tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh); >>> + tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1); >>> + >>> + return 0; >>> +} >>> + >>> static int tiadc_buffer_preenable(struct iio_dev *indio_dev) >>> { >>> struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> @@ -218,20 +297,30 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev) >>> static int tiadc_buffer_postenable(struct iio_dev *indio_dev) >>> { >>> struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> + unsigned int irq_enable; >>> unsigned int enb = 0; >>> u8 bit; >>> >>> tiadc_step_config(indio_dev); >>> - for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) >>> + for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) { >>> enb |= (get_adc_step_bit(adc_dev, bit) << 1); >>> + adc_dev->total_ch_enabled++; >>> + } >>> adc_dev->buffer_en_ch_steps = enb; >>> >>> + if (dma->chan) >>> + tiadc_start_dma(indio_dev); >>> + >>> am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb); >>> >>> tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES >>> | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); >>> - tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES >>> - | IRQENB_FIFO1OVRRUN); >>> + >>> + irq_enable = IRQENB_FIFO1OVRRUN; >>> + if (!dma->chan) >>> + irq_enable |= IRQENB_FIFO1THRES; >> This changes the non dma behaviour as we no longer set IRQENB_FIFO1THRES. >> Why? Was it wrong before? > > In non DMA case, dms->chan will be NULL and IRQENB_FIFO1THRES interrupt > will be enabled to pop the ADC samples. > oops. Thanks for pointing out how I'd misread this! So just after the ack from Lee now. Jonathan > Regards > Mugunthan V N > >>> + tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable); >>> >>> return 0; >>> } >>> @@ -239,12 +328,18 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev) >>> static int tiadc_buffer_predisable(struct iio_dev *indio_dev) >>> { >>> struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> int fifo1count, i, read; >>> >>> tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | >>> IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW)); >>> am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps); >>> adc_dev->buffer_en_ch_steps = 0; >>> + adc_dev->total_ch_enabled = 0; >>> + if (dma->chan) { >>> + tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2); >>> + dmaengine_terminate_async(dma->chan); >>> + } >>> >>> /* Flush FIFO of leftover data in the time it takes to disable adc */ >>> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); >>> @@ -430,6 +525,41 @@ static const struct iio_info tiadc_info = { >>> .driver_module = THIS_MODULE, >>> }; >>> >>> +static int tiadc_request_dma(struct platform_device *pdev, >>> + struct tiadc_device *adc_dev) >>> +{ >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> + dma_cap_mask_t mask; >>> + >>> + /* Default slave configuration parameters */ >>> + dma->conf.direction = DMA_DEV_TO_MEM; >>> + dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; >>> + dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1; >>> + >>> + dma_cap_zero(mask); >>> + dma_cap_set(DMA_CYCLIC, mask); >>> + >>> + /* Get a channel for RX */ >>> + dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1"); >>> + if (IS_ERR(dma->chan)) { >>> + int ret = PTR_ERR(dma->chan); >>> + >>> + dma->chan = NULL; >>> + return ret; >>> + } >>> + >>> + /* RX buffer */ >>> + dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE, >>> + &dma->addr, GFP_KERNEL); >>> + if (!dma->buf) >>> + goto err; >>> + >>> + return 0; >>> +err: >>> + dma_release_channel(dma->chan); >>> + return -ENOMEM; >>> +} >>> + >>> static int tiadc_parse_dt(struct platform_device *pdev, >>> struct tiadc_device *adc_dev) >>> { >>> @@ -512,8 +642,14 @@ static int tiadc_probe(struct platform_device *pdev) >>> >>> platform_set_drvdata(pdev, indio_dev); >>> >>> + err = tiadc_request_dma(pdev, adc_dev); >>> + if (err && err == -EPROBE_DEFER) >>> + goto err_dma; >>> + >>> return 0; >>> >>> +err_dma: >>> + iio_device_unregister(indio_dev); >>> err_buffer_unregister: >>> tiadc_iio_buffered_hardware_remove(indio_dev); >>> err_free_channels: >>> @@ -525,8 +661,14 @@ static int tiadc_remove(struct platform_device *pdev) >>> { >>> struct iio_dev *indio_dev = platform_get_drvdata(pdev); >>> struct tiadc_device *adc_dev = iio_priv(indio_dev); >>> + struct tiadc_dma *dma = &adc_dev->dma; >>> u32 step_en; >>> >>> + if (dma->chan) { >>> + dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE, >>> + dma->buf, dma->addr); >>> + dma_release_channel(dma->chan); >>> + } >>> iio_device_unregister(indio_dev); >>> tiadc_iio_buffered_hardware_remove(indio_dev); >>> tiadc_channels_remove(indio_dev); >>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h >>> index e45a208..b9a53e0 100644 >>> --- a/include/linux/mfd/ti_am335x_tscadc.h >>> +++ b/include/linux/mfd/ti_am335x_tscadc.h >>> @@ -23,6 +23,8 @@ >>> #define REG_IRQENABLE 0x02C >>> #define REG_IRQCLR 0x030 >>> #define REG_IRQWAKEUP 0x034 >>> +#define REG_DMAENABLE_SET 0x038 >>> +#define REG_DMAENABLE_CLEAR 0x03c >>> #define REG_CTRL 0x040 >>> #define REG_ADCFSM 0x044 >>> #define REG_CLKDIV 0x04C >>> @@ -36,6 +38,7 @@ >>> #define REG_FIFO0THR 0xE8 >>> #define REG_FIFO1CNT 0xF0 >>> #define REG_FIFO1THR 0xF4 >>> +#define REG_DMA1REQ 0xF8 >>> #define REG_FIFO0 0x100 >>> #define REG_FIFO1 0x200 >>> >>> @@ -126,6 +129,10 @@ >>> #define FIFOREAD_DATA_MASK (0xfff << 0) >>> #define FIFOREAD_CHNLID_MASK (0xf << 16) >>> >>> +/* DMA ENABLE/CLEAR Register */ >>> +#define DMA_FIFO0 BIT(0) >>> +#define DMA_FIFO1 BIT(1) >>> + >>> /* Sequencer Status */ >>> #define SEQ_STATUS BIT(5) >>> #define CHARGE_STEP 0x11 >>> >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >