// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) STMicroelectronics 2016 * Author: Benjamin Gaignard */ #include #include #include #include #include #define STM32_TIMERS_MAX_REGISTERS 0x3fc /* DIER register DMA enable bits */ static const u32 stm32_timers_dier_dmaen[STM32_TIMERS_MAX_DMAS] = { TIM_DIER_CC1DE, TIM_DIER_CC2DE, TIM_DIER_CC3DE, TIM_DIER_CC4DE, TIM_DIER_UIE, TIM_DIER_TDE, TIM_DIER_COMDE }; static void stm32_timers_dma_done(void *p) { struct stm32_timers_dma *dma = p; struct dma_tx_state state; enum dma_status status; status = dmaengine_tx_status(dma->chan, dma->chan->cookie, &state); if (status == DMA_COMPLETE) complete(&dma->completion); } /** * stm32_timers_dma_burst_read - Read from timers registers using DMA. * * Read from STM32 timers registers using DMA on a single event. * @dev: reference to stm32_timers MFD device * @buf: DMA'able destination buffer * @id: stm32_timers_dmas event identifier (ch[1..4], up, trig or com) * @reg: registers start offset for DMA to read from (like CCRx for capture) * @num_reg: number of registers to read upon each DMA request, starting @reg. * @bursts: number of bursts to read (e.g. like two for pwm period capture) * @tmo_ms: timeout (milliseconds) */ int stm32_timers_dma_burst_read(struct device *dev, u32 *buf, enum stm32_timers_dmas id, u32 reg, unsigned int num_reg, unsigned int bursts, unsigned long tmo_ms) { struct stm32_timers *ddata = dev_get_drvdata(dev); unsigned long timeout = msecs_to_jiffies(tmo_ms); struct regmap *regmap = ddata->regmap; struct stm32_timers_dma *dma = &ddata->dma; size_t len = num_reg * bursts * sizeof(u32); struct dma_async_tx_descriptor *desc; struct dma_slave_config config; dma_cookie_t cookie; dma_addr_t dma_buf; u32 dbl, dba; long err; int ret; /* Sanity check */ if (id < STM32_TIMERS_DMA_CH1 || id >= STM32_TIMERS_MAX_DMAS) return -EINVAL; if (!num_reg || !bursts || reg > STM32_TIMERS_MAX_REGISTERS || (reg + num_reg * sizeof(u32)) > STM32_TIMERS_MAX_REGISTERS) return -EINVAL; if (!dma->chans[id]) return -ENODEV; mutex_lock(&dma->lock); /* Select DMA channel in use */ dma->chan = dma->chans[id]; dma_buf = dma_map_single(dev, buf, len, DMA_FROM_DEVICE); if (dma_mapping_error(dev, dma_buf)) { ret = -ENOMEM; goto unlock; } /* Prepare DMA read from timer registers, using DMA burst mode */ memset(&config, 0, sizeof(config)); config.src_addr = (dma_addr_t)dma->phys_base + TIM_DMAR; config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; ret = dmaengine_slave_config(dma->chan, &config); if (ret) goto unmap; desc = dmaengine_prep_slave_single(dma->chan, dma_buf, len, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); if (!desc) { ret = -EBUSY; goto unmap; } desc->callback = stm32_timers_dma_done; desc->callback_param = dma; cookie = dmaengine_submit(desc); ret = dma_submit_error(cookie); if (ret) goto dma_term; reinit_completion(&dma->completion); dma_async_issue_pending(dma->chan); /* Setup and enable timer DMA burst mode */ dbl = FIELD_PREP(TIM_DCR_DBL, bursts - 1); dba = FIELD_PREP(TIM_DCR_DBA, reg >> 2); ret = regmap_write(regmap, TIM_DCR, dbl | dba); if (ret) goto dma_term; /* Clear pending flags before enabling DMA request */ ret = regmap_write(regmap, TIM_SR, 0); if (ret) goto dcr_clr; ret = regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id], stm32_timers_dier_dmaen[id]); if (ret) goto dcr_clr; err = wait_for_completion_interruptible_timeout(&dma->completion, timeout); if (err == 0) ret = -ETIMEDOUT; else if (err < 0) ret = err; regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id], 0); regmap_write(regmap, TIM_SR, 0); dcr_clr: regmap_write(regmap, TIM_DCR, 0); dma_term: dmaengine_terminate_all(dma->chan); unmap: dma_unmap_single(dev, dma_buf, len, DMA_FROM_DEVICE); unlock: dma->chan = NULL; mutex_unlock(&dma->lock); return ret; } EXPORT_SYMBOL_GPL(stm32_timers_dma_burst_read); static const struct regmap_config stm32_timers_regmap_cfg = { .reg_bits = 32, .val_bits = 32, .reg_stride = sizeof(u32), .max_register = STM32_TIMERS_MAX_REGISTERS, }; static void stm32_timers_get_arr_size(struct stm32_timers *ddata) { /* * Only the available bits will be written so when readback * we get the maximum value of auto reload register */ regmap_write(ddata->regmap, TIM_ARR, ~0L); regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr); regmap_write(ddata->regmap, TIM_ARR, 0x0); } static void stm32_timers_dma_probe(struct device *dev, struct stm32_timers *ddata) { int i; char name[4]; init_completion(&ddata->dma.completion); mutex_init(&ddata->dma.lock); /* Optional DMA support: get valid DMA channel(s) or NULL */ for (i = STM32_TIMERS_DMA_CH1; i <= STM32_TIMERS_DMA_CH4; i++) { snprintf(name, ARRAY_SIZE(name), "ch%1d", i + 1); ddata->dma.chans[i] = dma_request_slave_channel(dev, name); } ddata->dma.chans[STM32_TIMERS_DMA_UP] = dma_request_slave_channel(dev, "up"); ddata->dma.chans[STM32_TIMERS_DMA_TRIG] = dma_request_slave_channel(dev, "trig"); ddata->dma.chans[STM32_TIMERS_DMA_COM] = dma_request_slave_channel(dev, "com"); } static void stm32_timers_dma_remove(struct device *dev, struct stm32_timers *ddata) { int i; for (i = STM32_TIMERS_DMA_CH1; i < STM32_TIMERS_MAX_DMAS; i++) if (ddata->dma.chans[i]) dma_release_channel(ddata->dma.chans[i]); } static int stm32_timers_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct stm32_timers *ddata; struct resource *res; void __iomem *mmio; int ret; ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); if (!ddata) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); mmio = devm_ioremap_resource(dev, res); if (IS_ERR(mmio)) return PTR_ERR(mmio); /* Timer physical addr for DMA */ ddata->dma.phys_base = res->start; ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio, &stm32_timers_regmap_cfg); if (IS_ERR(ddata->regmap)) return PTR_ERR(ddata->regmap); ddata->clk = devm_clk_get(dev, NULL); if (IS_ERR(ddata->clk)) return PTR_ERR(ddata->clk); stm32_timers_get_arr_size(ddata); stm32_timers_dma_probe(dev, ddata); platform_set_drvdata(pdev, ddata); ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); if (ret) stm32_timers_dma_remove(dev, ddata); return ret; } static int stm32_timers_remove(struct platform_device *pdev) { struct stm32_timers *ddata = platform_get_drvdata(pdev); /* * Don't use devm_ here: enfore of_platform_depopulate() happens before * DMA are released, to avoid race on DMA. */ of_platform_depopulate(&pdev->dev); stm32_timers_dma_remove(&pdev->dev, ddata); return 0; } static const struct of_device_id stm32_timers_of_match[] = { { .compatible = "st,stm32-timers", }, { /* end node */ }, }; MODULE_DEVICE_TABLE(of, stm32_timers_of_match); static struct platform_driver stm32_timers_driver = { .probe = stm32_timers_probe, .remove = stm32_timers_remove, .driver = { .name = "stm32-timers", .of_match_table = stm32_timers_of_match, }, }; module_platform_driver(stm32_timers_driver); MODULE_DESCRIPTION("STMicroelectronics STM32 Timers"); MODULE_LICENSE("GPL v2");