Re: [PATCH v4 2/6] mfd: stm32-timers: add support for dmas

From: Dan Carpenter
Date: Tue Apr 17 2018 - 07:26:19 EST

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In reply to: Fabrice Gasnier: "Re: [PATCH v4 2/6] mfd: stm32-timers: add support for dmas"
Next in thread: Fabrice Gasnier: "[PATCH v4 4/6] pwm: stm32: improve capture by tuning counter prescaler"
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Hi Fabrice,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on pwm/for-next]
[also build test WARNING on v4.17-rc1 next-20180416]
[cannot apply to ljones-mfd/for-mfd-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Fabrice-Gasnier/Add-support-for-PWM-input-capture-on-STM32/20180417-052347
base: https://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm.git for-next

smatch warnings:
drivers/mfd/stm32-timers.c:165 stm32_timers_dma_burst_read() warn: warn: dma_mapping_error() doesn't return an error code

# https://github.com/0day-ci/linux/commit/402362a100e6b02b807fbebdc05b7159b565ffa5
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 402362a100e6b02b807fbebdc05b7159b565ffa5
vim +165 drivers/mfd/stm32-timers.c

402362a1 Fabrice Gasnier 2018-04-16 54
402362a1 Fabrice Gasnier 2018-04-16 55 /**
402362a1 Fabrice Gasnier 2018-04-16 56 * stm32_timers_dma_burst_read - Read from timers registers using DMA.
402362a1 Fabrice Gasnier 2018-04-16 57 *
402362a1 Fabrice Gasnier 2018-04-16 58 * Read from STM32 timers registers using DMA on a single event.
402362a1 Fabrice Gasnier 2018-04-16 59 * @dev: reference to stm32_timers MFD device
402362a1 Fabrice Gasnier 2018-04-16 60 * @buf: DMA'able destination buffer
402362a1 Fabrice Gasnier 2018-04-16 61 * @id: stm32_timers_dmas event identifier (ch[1..4], up, trig or com)
402362a1 Fabrice Gasnier 2018-04-16 62 * @reg: registers start offset for DMA to read from (like CCRx for capture)
402362a1 Fabrice Gasnier 2018-04-16 63 * @num_reg: number of registers to read upon each DMA request, starting @reg.
402362a1 Fabrice Gasnier 2018-04-16 64 * @bursts: number of bursts to read (e.g. like two for pwm period capture)
402362a1 Fabrice Gasnier 2018-04-16 65 * @tmo_ms: timeout (milliseconds)
402362a1 Fabrice Gasnier 2018-04-16 66 */
402362a1 Fabrice Gasnier 2018-04-16 67 int stm32_timers_dma_burst_read(struct device *dev, u32 *buf,
402362a1 Fabrice Gasnier 2018-04-16 68 enum stm32_timers_dmas id, u32 reg,
402362a1 Fabrice Gasnier 2018-04-16 69 unsigned int num_reg, unsigned int bursts,
402362a1 Fabrice Gasnier 2018-04-16 70 unsigned long tmo_ms)
402362a1 Fabrice Gasnier 2018-04-16 71 {
402362a1 Fabrice Gasnier 2018-04-16 72 struct stm32_timers *ddata = dev_get_drvdata(dev);
402362a1 Fabrice Gasnier 2018-04-16 73 unsigned long timeout = msecs_to_jiffies(tmo_ms);
402362a1 Fabrice Gasnier 2018-04-16 74 struct regmap *regmap = ddata->regmap;
402362a1 Fabrice Gasnier 2018-04-16 75 struct stm32_timers_dma *dma = ddata->dma;
402362a1 Fabrice Gasnier 2018-04-16 76 size_t len = num_reg * bursts * sizeof(u32);
402362a1 Fabrice Gasnier 2018-04-16 77 struct dma_async_tx_descriptor *desc;
402362a1 Fabrice Gasnier 2018-04-16 78 struct dma_slave_config config;
402362a1 Fabrice Gasnier 2018-04-16 79 dma_cookie_t cookie;
402362a1 Fabrice Gasnier 2018-04-16 80 dma_addr_t dma_buf;
402362a1 Fabrice Gasnier 2018-04-16 81 u32 dbl, dba;
402362a1 Fabrice Gasnier 2018-04-16 82 long err;
402362a1 Fabrice Gasnier 2018-04-16 83 int ret;
402362a1 Fabrice Gasnier 2018-04-16 84
402362a1 Fabrice Gasnier 2018-04-16 85 /* Sanity check */
402362a1 Fabrice Gasnier 2018-04-16 86 if (id < STM32_TIMERS_DMA_CH1 || id >= STM32_TIMERS_MAX_DMAS)
402362a1 Fabrice Gasnier 2018-04-16 87 return -EINVAL;
402362a1 Fabrice Gasnier 2018-04-16 88
402362a1 Fabrice Gasnier 2018-04-16 89 if (!num_reg || !bursts || reg > STM32_TIMERS_MAX_REGISTERS ||
402362a1 Fabrice Gasnier 2018-04-16 90 (reg + num_reg * sizeof(u32)) > STM32_TIMERS_MAX_REGISTERS)
402362a1 Fabrice Gasnier 2018-04-16 91 return -EINVAL;
402362a1 Fabrice Gasnier 2018-04-16 92
402362a1 Fabrice Gasnier 2018-04-16 93 if (!dma->chans[id])
402362a1 Fabrice Gasnier 2018-04-16 94 return -ENODEV;
402362a1 Fabrice Gasnier 2018-04-16 95 mutex_lock(&dma->lock);
402362a1 Fabrice Gasnier 2018-04-16 96
402362a1 Fabrice Gasnier 2018-04-16 97 /* Select DMA channel in use */
402362a1 Fabrice Gasnier 2018-04-16 98 dma->chan = dma->chans[id];
402362a1 Fabrice Gasnier 2018-04-16 99 dma_buf = dma_map_single(dev, buf, len, DMA_FROM_DEVICE);
402362a1 Fabrice Gasnier 2018-04-16 100 ret = dma_mapping_error(dev, dma_buf);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This should be:

if (dma_mapping_error(dev, dma_buf)) {
ret = -ENOMEM;
goto unlock;
}

402362a1 Fabrice Gasnier 2018-04-16 101 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 102 goto unlock;
402362a1 Fabrice Gasnier 2018-04-16 103
402362a1 Fabrice Gasnier 2018-04-16 104 /* Prepare DMA read from timer registers, using DMA burst mode */
402362a1 Fabrice Gasnier 2018-04-16 105 memset(&config, 0, sizeof(config));
402362a1 Fabrice Gasnier 2018-04-16 106 config.src_addr = (dma_addr_t)dma->phys_base + TIM_DMAR;
402362a1 Fabrice Gasnier 2018-04-16 107 config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
402362a1 Fabrice Gasnier 2018-04-16 108 ret = dmaengine_slave_config(dma->chan, &config);
402362a1 Fabrice Gasnier 2018-04-16 109 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 110 goto unmap;
402362a1 Fabrice Gasnier 2018-04-16 111
402362a1 Fabrice Gasnier 2018-04-16 112 desc = dmaengine_prep_slave_single(dma->chan, dma_buf, len,
402362a1 Fabrice Gasnier 2018-04-16 113 DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
402362a1 Fabrice Gasnier 2018-04-16 114 if (!desc) {
402362a1 Fabrice Gasnier 2018-04-16 115 ret = -EBUSY;
402362a1 Fabrice Gasnier 2018-04-16 116 goto unmap;
402362a1 Fabrice Gasnier 2018-04-16 117 }
402362a1 Fabrice Gasnier 2018-04-16 118
402362a1 Fabrice Gasnier 2018-04-16 119 desc->callback = stm32_timers_dma_done;
402362a1 Fabrice Gasnier 2018-04-16 120 desc->callback_param = dma;
402362a1 Fabrice Gasnier 2018-04-16 121 cookie = dmaengine_submit(desc);
402362a1 Fabrice Gasnier 2018-04-16 122 ret = dma_submit_error(cookie);
402362a1 Fabrice Gasnier 2018-04-16 123 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 124 goto dma_term;
402362a1 Fabrice Gasnier 2018-04-16 125
402362a1 Fabrice Gasnier 2018-04-16 126 reinit_completion(&dma->completion);
402362a1 Fabrice Gasnier 2018-04-16 127 dma_async_issue_pending(dma->chan);
402362a1 Fabrice Gasnier 2018-04-16 128
402362a1 Fabrice Gasnier 2018-04-16 129 /* Setup and enable timer DMA burst mode */
402362a1 Fabrice Gasnier 2018-04-16 130 dbl = FIELD_PREP(TIM_DCR_DBL, bursts - 1);
402362a1 Fabrice Gasnier 2018-04-16 131 dba = FIELD_PREP(TIM_DCR_DBA, reg >> 2);
402362a1 Fabrice Gasnier 2018-04-16 132 ret = regmap_write(regmap, TIM_DCR, dbl | dba);
402362a1 Fabrice Gasnier 2018-04-16 133 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 134 goto dma_term;
402362a1 Fabrice Gasnier 2018-04-16 135
402362a1 Fabrice Gasnier 2018-04-16 136 /* Clear pending flags before enabling DMA request */
402362a1 Fabrice Gasnier 2018-04-16 137 ret = regmap_write(regmap, TIM_SR, 0);
402362a1 Fabrice Gasnier 2018-04-16 138 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 139 goto dcr_clr;
402362a1 Fabrice Gasnier 2018-04-16 140
402362a1 Fabrice Gasnier 2018-04-16 141 ret = regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id],
402362a1 Fabrice Gasnier 2018-04-16 142 stm32_timers_dier_dmaen[id]);
402362a1 Fabrice Gasnier 2018-04-16 143 if (ret)
402362a1 Fabrice Gasnier 2018-04-16 144 goto dcr_clr;
402362a1 Fabrice Gasnier 2018-04-16 145
402362a1 Fabrice Gasnier 2018-04-16 146 err = wait_for_completion_interruptible_timeout(&dma->completion,
402362a1 Fabrice Gasnier 2018-04-16 147 timeout);
402362a1 Fabrice Gasnier 2018-04-16 148 if (err == 0)
402362a1 Fabrice Gasnier 2018-04-16 149 ret = -ETIMEDOUT;
402362a1 Fabrice Gasnier 2018-04-16 150 else if (err < 0)
402362a1 Fabrice Gasnier 2018-04-16 151 ret = err;
402362a1 Fabrice Gasnier 2018-04-16 152
402362a1 Fabrice Gasnier 2018-04-16 153 regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id], 0);
402362a1 Fabrice Gasnier 2018-04-16 154 regmap_write(regmap, TIM_SR, 0);
402362a1 Fabrice Gasnier 2018-04-16 155 dcr_clr:
402362a1 Fabrice Gasnier 2018-04-16 156 regmap_write(regmap, TIM_DCR, 0);
402362a1 Fabrice Gasnier 2018-04-16 157 dma_term:
402362a1 Fabrice Gasnier 2018-04-16 158 dmaengine_terminate_all(dma->chan);
402362a1 Fabrice Gasnier 2018-04-16 159 unmap:
402362a1 Fabrice Gasnier 2018-04-16 160 dma_unmap_single(dev, dma_buf, len, DMA_FROM_DEVICE);
402362a1 Fabrice Gasnier 2018-04-16 161 unlock:
402362a1 Fabrice Gasnier 2018-04-16 162 dma->chan = NULL;
402362a1 Fabrice Gasnier 2018-04-16 163 mutex_unlock(&dma->lock);
402362a1 Fabrice Gasnier 2018-04-16 164
402362a1 Fabrice Gasnier 2018-04-16 @165 return ret;
402362a1 Fabrice Gasnier 2018-04-16 166 }
402362a1 Fabrice Gasnier 2018-04-16 167 EXPORT_SYMBOL_GPL(stm32_timers_dma_burst_read);
402362a1 Fabrice Gasnier 2018-04-16 168

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Next message: Mark Brown: "Applied "ASoC: rt1305: fix platform_no_drv_owner.cocci warnings" to the asoc tree"
Previous message: Chen-Yu Tsai: "Re: [PATCH v6 01/11] ARM: sunxi: smp: Move assembly code into a file"
In reply to: Fabrice Gasnier: "Re: [PATCH v4 2/6] mfd: stm32-timers: add support for dmas"
Next in thread: Fabrice Gasnier: "[PATCH v4 4/6] pwm: stm32: improve capture by tuning counter prescaler"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]