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Diffstat (limited to '')
| -rw-r--r-- | drivers/dma/stm32-dma.c | 1793 |
1 files changed, 1793 insertions, 0 deletions
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c new file mode 100644 index 0000000000..9840594a6a --- /dev/null +++ b/drivers/dma/stm32-dma.c @@ -0,0 +1,1793 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for STM32 DMA controller + * + * Inspired by dma-jz4740.c and tegra20-apb-dma.c + * + * Copyright (C) M'boumba Cedric Madianga 2015 + * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com> + * Pierre-Yves Mordret <pierre-yves.mordret@st.com> + */ + +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/iopoll.h> +#include <linux/jiffies.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_dma.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/sched.h> +#include <linux/slab.h> + +#include "virt-dma.h" + +#define STM32_DMA_LISR 0x0000 /* DMA Low Int Status Reg */ +#define STM32_DMA_HISR 0x0004 /* DMA High Int Status Reg */ +#define STM32_DMA_ISR(n) (((n) & 4) ? STM32_DMA_HISR : STM32_DMA_LISR) +#define STM32_DMA_LIFCR 0x0008 /* DMA Low Int Flag Clear Reg */ +#define STM32_DMA_HIFCR 0x000c /* DMA High Int Flag Clear Reg */ +#define STM32_DMA_IFCR(n) (((n) & 4) ? STM32_DMA_HIFCR : STM32_DMA_LIFCR) +#define STM32_DMA_TCI BIT(5) /* Transfer Complete Interrupt */ +#define STM32_DMA_HTI BIT(4) /* Half Transfer Interrupt */ +#define STM32_DMA_TEI BIT(3) /* Transfer Error Interrupt */ +#define STM32_DMA_DMEI BIT(2) /* Direct Mode Error Interrupt */ +#define STM32_DMA_FEI BIT(0) /* FIFO Error Interrupt */ +#define STM32_DMA_MASKI (STM32_DMA_TCI \ + | STM32_DMA_TEI \ + | STM32_DMA_DMEI \ + | STM32_DMA_FEI) +/* + * If (chan->id % 4) is 2 or 3, left shift the mask by 16 bits; + * if (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits. + */ +#define STM32_DMA_FLAGS_SHIFT(n) ({ typeof(n) (_n) = (n); \ + (((_n) & 2) << 3) | (((_n) & 1) * 6); }) + +/* DMA Stream x Configuration Register */ +#define STM32_DMA_SCR(x) (0x0010 + 0x18 * (x)) /* x = 0..7 */ +#define STM32_DMA_SCR_REQ_MASK GENMASK(27, 25) +#define STM32_DMA_SCR_MBURST_MASK GENMASK(24, 23) +#define STM32_DMA_SCR_PBURST_MASK GENMASK(22, 21) +#define STM32_DMA_SCR_PL_MASK GENMASK(17, 16) +#define STM32_DMA_SCR_MSIZE_MASK GENMASK(14, 13) +#define STM32_DMA_SCR_PSIZE_MASK GENMASK(12, 11) +#define STM32_DMA_SCR_DIR_MASK GENMASK(7, 6) +#define STM32_DMA_SCR_TRBUFF BIT(20) /* Bufferable transfer for USART/UART */ +#define STM32_DMA_SCR_CT BIT(19) /* Target in double buffer */ +#define STM32_DMA_SCR_DBM BIT(18) /* Double Buffer Mode */ +#define STM32_DMA_SCR_PINCOS BIT(15) /* Peripheral inc offset size */ +#define STM32_DMA_SCR_MINC BIT(10) /* Memory increment mode */ +#define STM32_DMA_SCR_PINC BIT(9) /* Peripheral increment mode */ +#define STM32_DMA_SCR_CIRC BIT(8) /* Circular mode */ +#define STM32_DMA_SCR_PFCTRL BIT(5) /* Peripheral Flow Controller */ +#define STM32_DMA_SCR_TCIE BIT(4) /* Transfer Complete Int Enable + */ +#define STM32_DMA_SCR_TEIE BIT(2) /* Transfer Error Int Enable */ +#define STM32_DMA_SCR_DMEIE BIT(1) /* Direct Mode Err Int Enable */ +#define STM32_DMA_SCR_EN BIT(0) /* Stream Enable */ +#define STM32_DMA_SCR_CFG_MASK (STM32_DMA_SCR_PINC \ + | STM32_DMA_SCR_MINC \ + | STM32_DMA_SCR_PINCOS \ + | STM32_DMA_SCR_PL_MASK) +#define STM32_DMA_SCR_IRQ_MASK (STM32_DMA_SCR_TCIE \ + | STM32_DMA_SCR_TEIE \ + | STM32_DMA_SCR_DMEIE) + +/* DMA Stream x number of data register */ +#define STM32_DMA_SNDTR(x) (0x0014 + 0x18 * (x)) + +/* DMA stream peripheral address register */ +#define STM32_DMA_SPAR(x) (0x0018 + 0x18 * (x)) + +/* DMA stream x memory 0 address register */ +#define STM32_DMA_SM0AR(x) (0x001c + 0x18 * (x)) + +/* DMA stream x memory 1 address register */ +#define STM32_DMA_SM1AR(x) (0x0020 + 0x18 * (x)) + +/* DMA stream x FIFO control register */ +#define STM32_DMA_SFCR(x) (0x0024 + 0x18 * (x)) +#define STM32_DMA_SFCR_FTH_MASK GENMASK(1, 0) +#define STM32_DMA_SFCR_FEIE BIT(7) /* FIFO error interrupt enable */ +#define STM32_DMA_SFCR_DMDIS BIT(2) /* Direct mode disable */ +#define STM32_DMA_SFCR_MASK (STM32_DMA_SFCR_FEIE \ + | STM32_DMA_SFCR_DMDIS) + +/* DMA direction */ +#define STM32_DMA_DEV_TO_MEM 0x00 +#define STM32_DMA_MEM_TO_DEV 0x01 +#define STM32_DMA_MEM_TO_MEM 0x02 + +/* DMA priority level */ +#define STM32_DMA_PRIORITY_LOW 0x00 +#define STM32_DMA_PRIORITY_MEDIUM 0x01 +#define STM32_DMA_PRIORITY_HIGH 0x02 +#define STM32_DMA_PRIORITY_VERY_HIGH 0x03 + +/* DMA FIFO threshold selection */ +#define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL 0x00 +#define STM32_DMA_FIFO_THRESHOLD_HALFFULL 0x01 +#define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL 0x02 +#define STM32_DMA_FIFO_THRESHOLD_FULL 0x03 +#define STM32_DMA_FIFO_THRESHOLD_NONE 0x04 + +#define STM32_DMA_MAX_DATA_ITEMS 0xffff +/* + * Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter + * gather at boundary. Thus it's safer to round down this value on FIFO + * size (16 Bytes) + */ +#define STM32_DMA_ALIGNED_MAX_DATA_ITEMS \ + ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16) +#define STM32_DMA_MAX_CHANNELS 0x08 +#define STM32_DMA_MAX_REQUEST_ID 0x08 +#define STM32_DMA_MAX_DATA_PARAM 0x03 +#define STM32_DMA_FIFO_SIZE 16 /* FIFO is 16 bytes */ +#define STM32_DMA_MIN_BURST 4 +#define STM32_DMA_MAX_BURST 16 + +/* DMA Features */ +#define STM32_DMA_THRESHOLD_FTR_MASK GENMASK(1, 0) +#define STM32_DMA_DIRECT_MODE_MASK BIT(2) +#define STM32_DMA_ALT_ACK_MODE_MASK BIT(4) +#define STM32_DMA_MDMA_STREAM_ID_MASK GENMASK(19, 16) + +enum stm32_dma_width { + STM32_DMA_BYTE, + STM32_DMA_HALF_WORD, + STM32_DMA_WORD, +}; + +enum stm32_dma_burst_size { + STM32_DMA_BURST_SINGLE, + STM32_DMA_BURST_INCR4, + STM32_DMA_BURST_INCR8, + STM32_DMA_BURST_INCR16, +}; + +/** + * struct stm32_dma_cfg - STM32 DMA custom configuration + * @channel_id: channel ID + * @request_line: DMA request + * @stream_config: 32bit mask specifying the DMA channel configuration + * @features: 32bit mask specifying the DMA Feature list + */ +struct stm32_dma_cfg { + u32 channel_id; + u32 request_line; + u32 stream_config; + u32 features; +}; + +struct stm32_dma_chan_reg { + u32 dma_lisr; + u32 dma_hisr; + u32 dma_lifcr; + u32 dma_hifcr; + u32 dma_scr; + u32 dma_sndtr; + u32 dma_spar; + u32 dma_sm0ar; + u32 dma_sm1ar; + u32 dma_sfcr; +}; + +struct stm32_dma_sg_req { + u32 len; + struct stm32_dma_chan_reg chan_reg; +}; + +struct stm32_dma_desc { + struct virt_dma_desc vdesc; + bool cyclic; + u32 num_sgs; + struct stm32_dma_sg_req sg_req[]; +}; + +/** + * struct stm32_dma_mdma_config - STM32 DMA MDMA configuration + * @stream_id: DMA request to trigger STM32 MDMA transfer + * @ifcr: DMA interrupt flag clear register address, + * used by STM32 MDMA to clear DMA Transfer Complete flag + * @tcf: DMA Transfer Complete flag + */ +struct stm32_dma_mdma_config { + u32 stream_id; + u32 ifcr; + u32 tcf; +}; + +struct stm32_dma_chan { + struct virt_dma_chan vchan; + bool config_init; + bool busy; + u32 id; + u32 irq; + struct stm32_dma_desc *desc; + u32 next_sg; + struct dma_slave_config dma_sconfig; + struct stm32_dma_chan_reg chan_reg; + u32 threshold; + u32 mem_burst; + u32 mem_width; + enum dma_status status; + bool trig_mdma; + struct stm32_dma_mdma_config mdma_config; +}; + +struct stm32_dma_device { + struct dma_device ddev; + void __iomem *base; + struct clk *clk; + bool mem2mem; + struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS]; +}; + +static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan) +{ + return container_of(chan->vchan.chan.device, struct stm32_dma_device, + ddev); +} + +static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c) +{ + return container_of(c, struct stm32_dma_chan, vchan.chan); +} + +static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc) +{ + return container_of(vdesc, struct stm32_dma_desc, vdesc); +} + +static struct device *chan2dev(struct stm32_dma_chan *chan) +{ + return &chan->vchan.chan.dev->device; +} + +static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg) +{ + return readl_relaxed(dmadev->base + reg); +} + +static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val) +{ + writel_relaxed(val, dmadev->base + reg); +} + +static int stm32_dma_get_width(struct stm32_dma_chan *chan, + enum dma_slave_buswidth width) +{ + switch (width) { + case DMA_SLAVE_BUSWIDTH_1_BYTE: + return STM32_DMA_BYTE; + case DMA_SLAVE_BUSWIDTH_2_BYTES: + return STM32_DMA_HALF_WORD; + case DMA_SLAVE_BUSWIDTH_4_BYTES: + return STM32_DMA_WORD; + default: + dev_err(chan2dev(chan), "Dma bus width not supported\n"); + return -EINVAL; + } +} + +static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len, + dma_addr_t buf_addr, + u32 threshold) +{ + enum dma_slave_buswidth max_width; + + if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL) + max_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + else + max_width = DMA_SLAVE_BUSWIDTH_2_BYTES; + + while ((buf_len < max_width || buf_len % max_width) && + max_width > DMA_SLAVE_BUSWIDTH_1_BYTE) + max_width = max_width >> 1; + + if (buf_addr & (max_width - 1)) + max_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + + return max_width; +} + +static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold, + enum dma_slave_buswidth width) +{ + u32 remaining; + + if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE) + return false; + + if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) { + if (burst != 0) { + /* + * If number of beats fit in several whole bursts + * this configuration is allowed. + */ + remaining = ((STM32_DMA_FIFO_SIZE / width) * + (threshold + 1) / 4) % burst; + + if (remaining == 0) + return true; + } else { + return true; + } + } + + return false; +} + +static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold) +{ + /* If FIFO direct mode, burst is not possible */ + if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE) + return false; + + /* + * Buffer or period length has to be aligned on FIFO depth. + * Otherwise bytes may be stuck within FIFO at buffer or period + * length. + */ + return ((buf_len % ((threshold + 1) * 4)) == 0); +} + +static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold, + enum dma_slave_buswidth width) +{ + u32 best_burst = max_burst; + + if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold)) + return 0; + + while ((buf_len < best_burst * width && best_burst > 1) || + !stm32_dma_fifo_threshold_is_allowed(best_burst, threshold, + width)) { + if (best_burst > STM32_DMA_MIN_BURST) + best_burst = best_burst >> 1; + else + best_burst = 0; + } + + return best_burst; +} + +static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst) +{ + switch (maxburst) { + case 0: + case 1: + return STM32_DMA_BURST_SINGLE; + case 4: + return STM32_DMA_BURST_INCR4; + case 8: + return STM32_DMA_BURST_INCR8; + case 16: + return STM32_DMA_BURST_INCR16; + default: + dev_err(chan2dev(chan), "Dma burst size not supported\n"); + return -EINVAL; + } +} + +static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan, + u32 src_burst, u32 dst_burst) +{ + chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK; + chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE; + + if (!src_burst && !dst_burst) { + /* Using direct mode */ + chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE; + } else { + /* Using FIFO mode */ + chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK; + } +} + +static int stm32_dma_slave_config(struct dma_chan *c, + struct dma_slave_config *config) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + + memcpy(&chan->dma_sconfig, config, sizeof(*config)); + + /* Check if user is requesting DMA to trigger STM32 MDMA */ + if (config->peripheral_size) { + config->peripheral_config = &chan->mdma_config; + config->peripheral_size = sizeof(chan->mdma_config); + chan->trig_mdma = true; + } + + chan->config_init = true; + + return 0; +} + +static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 flags, dma_isr; + + /* + * Read "flags" from DMA_xISR register corresponding to the selected + * DMA channel at the correct bit offset inside that register. + */ + + dma_isr = stm32_dma_read(dmadev, STM32_DMA_ISR(chan->id)); + flags = dma_isr >> STM32_DMA_FLAGS_SHIFT(chan->id); + + return flags & STM32_DMA_MASKI; +} + +static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 dma_ifcr; + + /* + * Write "flags" to the DMA_xIFCR register corresponding to the selected + * DMA channel at the correct bit offset inside that register. + */ + flags &= STM32_DMA_MASKI; + dma_ifcr = flags << STM32_DMA_FLAGS_SHIFT(chan->id); + + stm32_dma_write(dmadev, STM32_DMA_IFCR(chan->id), dma_ifcr); +} + +static int stm32_dma_disable_chan(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 dma_scr, id, reg; + + id = chan->id; + reg = STM32_DMA_SCR(id); + dma_scr = stm32_dma_read(dmadev, reg); + + if (dma_scr & STM32_DMA_SCR_EN) { + dma_scr &= ~STM32_DMA_SCR_EN; + stm32_dma_write(dmadev, reg, dma_scr); + + return readl_relaxed_poll_timeout_atomic(dmadev->base + reg, + dma_scr, !(dma_scr & STM32_DMA_SCR_EN), + 10, 1000000); + } + + return 0; +} + +static void stm32_dma_stop(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 dma_scr, dma_sfcr, status; + int ret; + + /* Disable interrupts */ + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id)); + dma_scr &= ~STM32_DMA_SCR_IRQ_MASK; + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr); + dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id)); + dma_sfcr &= ~STM32_DMA_SFCR_FEIE; + stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr); + + /* Disable DMA */ + ret = stm32_dma_disable_chan(chan); + if (ret < 0) + return; + + /* Clear interrupt status if it is there */ + status = stm32_dma_irq_status(chan); + if (status) { + dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n", + __func__, status); + stm32_dma_irq_clear(chan, status); + } + + chan->busy = false; + chan->status = DMA_COMPLETE; +} + +static int stm32_dma_terminate_all(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + unsigned long flags; + LIST_HEAD(head); + + spin_lock_irqsave(&chan->vchan.lock, flags); + + if (chan->desc) { + dma_cookie_complete(&chan->desc->vdesc.tx); + vchan_terminate_vdesc(&chan->desc->vdesc); + if (chan->busy) + stm32_dma_stop(chan); + chan->desc = NULL; + } + + vchan_get_all_descriptors(&chan->vchan, &head); + spin_unlock_irqrestore(&chan->vchan.lock, flags); + vchan_dma_desc_free_list(&chan->vchan, &head); + + return 0; +} + +static void stm32_dma_synchronize(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + + vchan_synchronize(&chan->vchan); +} + +static void stm32_dma_dump_reg(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id)); + u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id)); + u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id)); + u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id)); + u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id)); + u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id)); + + dev_dbg(chan2dev(chan), "SCR: 0x%08x\n", scr); + dev_dbg(chan2dev(chan), "NDTR: 0x%08x\n", ndtr); + dev_dbg(chan2dev(chan), "SPAR: 0x%08x\n", spar); + dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar); + dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar); + dev_dbg(chan2dev(chan), "SFCR: 0x%08x\n", sfcr); +} + +static void stm32_dma_sg_inc(struct stm32_dma_chan *chan) +{ + chan->next_sg++; + if (chan->desc->cyclic && (chan->next_sg == chan->desc->num_sgs)) + chan->next_sg = 0; +} + +static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan); + +static void stm32_dma_start_transfer(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + struct virt_dma_desc *vdesc; + struct stm32_dma_sg_req *sg_req; + struct stm32_dma_chan_reg *reg; + u32 status; + int ret; + + ret = stm32_dma_disable_chan(chan); + if (ret < 0) + return; + + if (!chan->desc) { + vdesc = vchan_next_desc(&chan->vchan); + if (!vdesc) + return; + + list_del(&vdesc->node); + + chan->desc = to_stm32_dma_desc(vdesc); + chan->next_sg = 0; + } + + if (chan->next_sg == chan->desc->num_sgs) + chan->next_sg = 0; + + sg_req = &chan->desc->sg_req[chan->next_sg]; + reg = &sg_req->chan_reg; + + /* When DMA triggers STM32 MDMA, DMA Transfer Complete is managed by STM32 MDMA */ + if (chan->trig_mdma && chan->dma_sconfig.direction != DMA_MEM_TO_DEV) + reg->dma_scr &= ~STM32_DMA_SCR_TCIE; + + reg->dma_scr &= ~STM32_DMA_SCR_EN; + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr); + stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar); + stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar); + stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr); + stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar); + stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr); + + stm32_dma_sg_inc(chan); + + /* Clear interrupt status if it is there */ + status = stm32_dma_irq_status(chan); + if (status) + stm32_dma_irq_clear(chan, status); + + if (chan->desc->cyclic) + stm32_dma_configure_next_sg(chan); + + stm32_dma_dump_reg(chan); + + /* Start DMA */ + chan->busy = true; + chan->status = DMA_IN_PROGRESS; + reg->dma_scr |= STM32_DMA_SCR_EN; + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr); + + dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan); +} + +static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + struct stm32_dma_sg_req *sg_req; + u32 dma_scr, dma_sm0ar, dma_sm1ar, id; + + id = chan->id; + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + + sg_req = &chan->desc->sg_req[chan->next_sg]; + + if (dma_scr & STM32_DMA_SCR_CT) { + dma_sm0ar = sg_req->chan_reg.dma_sm0ar; + stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar); + dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n", + stm32_dma_read(dmadev, STM32_DMA_SM0AR(id))); + } else { + dma_sm1ar = sg_req->chan_reg.dma_sm1ar; + stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar); + dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n", + stm32_dma_read(dmadev, STM32_DMA_SM1AR(id))); + } +} + +static void stm32_dma_handle_chan_paused(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 dma_scr; + + /* + * Read and store current remaining data items and peripheral/memory addresses to be + * updated on resume + */ + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id)); + /* + * Transfer can be paused while between a previous resume and reconfiguration on transfer + * complete. If transfer is cyclic and CIRC and DBM have been deactivated for resume, need + * to set it here in SCR backup to ensure a good reconfiguration on transfer complete. + */ + if (chan->desc && chan->desc->cyclic) { + if (chan->desc->num_sgs == 1) + dma_scr |= STM32_DMA_SCR_CIRC; + else + dma_scr |= STM32_DMA_SCR_DBM; + } + chan->chan_reg.dma_scr = dma_scr; + + /* + * Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt, otherwise + * on resume NDTR autoreload value will be wrong (lower than the initial period length) + */ + if (chan->desc && chan->desc->cyclic) { + dma_scr &= ~(STM32_DMA_SCR_DBM | STM32_DMA_SCR_CIRC); + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr); + } + + chan->chan_reg.dma_sndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id)); + + chan->status = DMA_PAUSED; + + dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan); +} + +static void stm32_dma_post_resume_reconfigure(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + struct stm32_dma_sg_req *sg_req; + u32 dma_scr, status, id; + + id = chan->id; + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + + /* Clear interrupt status if it is there */ + status = stm32_dma_irq_status(chan); + if (status) + stm32_dma_irq_clear(chan, status); + + if (!chan->next_sg) + sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1]; + else + sg_req = &chan->desc->sg_req[chan->next_sg - 1]; + + /* Reconfigure NDTR with the initial value */ + stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), sg_req->chan_reg.dma_sndtr); + + /* Restore SPAR */ + stm32_dma_write(dmadev, STM32_DMA_SPAR(id), sg_req->chan_reg.dma_spar); + + /* Restore SM0AR/SM1AR whatever DBM/CT as they may have been modified */ + stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sg_req->chan_reg.dma_sm0ar); + stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sg_req->chan_reg.dma_sm1ar); + + /* Reactivate CIRC/DBM if needed */ + if (chan->chan_reg.dma_scr & STM32_DMA_SCR_DBM) { + dma_scr |= STM32_DMA_SCR_DBM; + /* Restore CT */ + if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CT) + dma_scr &= ~STM32_DMA_SCR_CT; + else + dma_scr |= STM32_DMA_SCR_CT; + } else if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CIRC) { + dma_scr |= STM32_DMA_SCR_CIRC; + } + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr); + + stm32_dma_configure_next_sg(chan); + + stm32_dma_dump_reg(chan); + + dma_scr |= STM32_DMA_SCR_EN; + stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr); + + dev_dbg(chan2dev(chan), "vchan %pK: reconfigured after pause/resume\n", &chan->vchan); +} + +static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan, u32 scr) +{ + if (!chan->desc) + return; + + if (chan->desc->cyclic) { + vchan_cyclic_callback(&chan->desc->vdesc); + if (chan->trig_mdma) + return; + stm32_dma_sg_inc(chan); + /* cyclic while CIRC/DBM disable => post resume reconfiguration needed */ + if (!(scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM))) + stm32_dma_post_resume_reconfigure(chan); + else if (scr & STM32_DMA_SCR_DBM) + stm32_dma_configure_next_sg(chan); + } else { + chan->busy = false; + chan->status = DMA_COMPLETE; + if (chan->next_sg == chan->desc->num_sgs) { + vchan_cookie_complete(&chan->desc->vdesc); + chan->desc = NULL; + } + stm32_dma_start_transfer(chan); + } +} + +static irqreturn_t stm32_dma_chan_irq(int irq, void *devid) +{ + struct stm32_dma_chan *chan = devid; + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + u32 status, scr, sfcr; + + spin_lock(&chan->vchan.lock); + + status = stm32_dma_irq_status(chan); + scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id)); + sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id)); + + if (status & STM32_DMA_FEI) { + stm32_dma_irq_clear(chan, STM32_DMA_FEI); + status &= ~STM32_DMA_FEI; + if (sfcr & STM32_DMA_SFCR_FEIE) { + if (!(scr & STM32_DMA_SCR_EN) && + !(status & STM32_DMA_TCI)) + dev_err(chan2dev(chan), "FIFO Error\n"); + else + dev_dbg(chan2dev(chan), "FIFO over/underrun\n"); + } + } + if (status & STM32_DMA_DMEI) { + stm32_dma_irq_clear(chan, STM32_DMA_DMEI); + status &= ~STM32_DMA_DMEI; + if (sfcr & STM32_DMA_SCR_DMEIE) + dev_dbg(chan2dev(chan), "Direct mode overrun\n"); + } + + if (status & STM32_DMA_TCI) { + stm32_dma_irq_clear(chan, STM32_DMA_TCI); + if (scr & STM32_DMA_SCR_TCIE) { + if (chan->status != DMA_PAUSED) + stm32_dma_handle_chan_done(chan, scr); + } + status &= ~STM32_DMA_TCI; + } + + if (status & STM32_DMA_HTI) { + stm32_dma_irq_clear(chan, STM32_DMA_HTI); + status &= ~STM32_DMA_HTI; + } + + if (status) { + stm32_dma_irq_clear(chan, status); + dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status); + if (!(scr & STM32_DMA_SCR_EN)) + dev_err(chan2dev(chan), "chan disabled by HW\n"); + } + + spin_unlock(&chan->vchan.lock); + + return IRQ_HANDLED; +} + +static void stm32_dma_issue_pending(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + unsigned long flags; + + spin_lock_irqsave(&chan->vchan.lock, flags); + if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) { + dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan); + stm32_dma_start_transfer(chan); + + } + spin_unlock_irqrestore(&chan->vchan.lock, flags); +} + +static int stm32_dma_pause(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + unsigned long flags; + int ret; + + if (chan->status != DMA_IN_PROGRESS) + return -EPERM; + + spin_lock_irqsave(&chan->vchan.lock, flags); + + ret = stm32_dma_disable_chan(chan); + if (!ret) + stm32_dma_handle_chan_paused(chan); + + spin_unlock_irqrestore(&chan->vchan.lock, flags); + + return ret; +} + +static int stm32_dma_resume(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + struct stm32_dma_chan_reg chan_reg = chan->chan_reg; + u32 id = chan->id, scr, ndtr, offset, spar, sm0ar, sm1ar; + struct stm32_dma_sg_req *sg_req; + unsigned long flags; + + if (chan->status != DMA_PAUSED) + return -EPERM; + + scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + if (WARN_ON(scr & STM32_DMA_SCR_EN)) + return -EPERM; + + spin_lock_irqsave(&chan->vchan.lock, flags); + + /* sg_reg[prev_sg] contains original ndtr, sm0ar and sm1ar before pausing the transfer */ + if (!chan->next_sg) + sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1]; + else + sg_req = &chan->desc->sg_req[chan->next_sg - 1]; + + ndtr = sg_req->chan_reg.dma_sndtr; + offset = (ndtr - chan_reg.dma_sndtr); + offset <<= FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, chan_reg.dma_scr); + spar = sg_req->chan_reg.dma_spar; + sm0ar = sg_req->chan_reg.dma_sm0ar; + sm1ar = sg_req->chan_reg.dma_sm1ar; + + /* + * The peripheral and/or memory addresses have to be updated in order to adjust the + * address pointers. Need to check increment. + */ + if (chan_reg.dma_scr & STM32_DMA_SCR_PINC) + stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar + offset); + else + stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar); + + if (!(chan_reg.dma_scr & STM32_DMA_SCR_MINC)) + offset = 0; + + /* + * In case of DBM, the current target could be SM1AR. + * Need to temporarily deactivate CIRC/DBM to finish the current transfer, so + * SM0AR becomes the current target and must be updated with SM1AR + offset if CT=1. + */ + if ((chan_reg.dma_scr & STM32_DMA_SCR_DBM) && (chan_reg.dma_scr & STM32_DMA_SCR_CT)) + stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sm1ar + offset); + else + stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sm0ar + offset); + + /* NDTR must be restored otherwise internal HW counter won't be correctly reset */ + stm32_dma_write(dmadev, STM32_DMA_SNDTR(id), chan_reg.dma_sndtr); + + /* + * Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt, + * otherwise NDTR autoreload value will be wrong (lower than the initial period length) + */ + if (chan_reg.dma_scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM)) + chan_reg.dma_scr &= ~(STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM); + + if (chan_reg.dma_scr & STM32_DMA_SCR_DBM) + stm32_dma_configure_next_sg(chan); + + stm32_dma_dump_reg(chan); + + /* The stream may then be re-enabled to restart transfer from the point it was stopped */ + chan->status = DMA_IN_PROGRESS; + chan_reg.dma_scr |= STM32_DMA_SCR_EN; + stm32_dma_write(dmadev, STM32_DMA_SCR(id), chan_reg.dma_scr); + + spin_unlock_irqrestore(&chan->vchan.lock, flags); + + dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan); + + return 0; +} + +static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, + enum dma_transfer_direction direction, + enum dma_slave_buswidth *buswidth, + u32 buf_len, dma_addr_t buf_addr) +{ + enum dma_slave_buswidth src_addr_width, dst_addr_width; + int src_bus_width, dst_bus_width; + int src_burst_size, dst_burst_size; + u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst; + u32 dma_scr, fifoth; + + src_addr_width = chan->dma_sconfig.src_addr_width; + dst_addr_width = chan->dma_sconfig.dst_addr_width; + src_maxburst = chan->dma_sconfig.src_maxburst; + dst_maxburst = chan->dma_sconfig.dst_maxburst; + fifoth = chan->threshold; + + switch (direction) { + case DMA_MEM_TO_DEV: + /* Set device data size */ + dst_bus_width = stm32_dma_get_width(chan, dst_addr_width); + if (dst_bus_width < 0) + return dst_bus_width; + + /* Set device burst size */ + dst_best_burst = stm32_dma_get_best_burst(buf_len, + dst_maxburst, + fifoth, + dst_addr_width); + + dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst); + if (dst_burst_size < 0) + return dst_burst_size; + + /* Set memory data size */ + src_addr_width = stm32_dma_get_max_width(buf_len, buf_addr, + fifoth); + chan->mem_width = src_addr_width; + src_bus_width = stm32_dma_get_width(chan, src_addr_width); + if (src_bus_width < 0) + return src_bus_width; + + /* + * Set memory burst size - burst not possible if address is not aligned on + * the address boundary equal to the size of the transfer + */ + if (buf_addr & (buf_len - 1)) + src_maxburst = 1; + else + src_maxburst = STM32_DMA_MAX_BURST; + src_best_burst = stm32_dma_get_best_burst(buf_len, + src_maxburst, + fifoth, + src_addr_width); + src_burst_size = stm32_dma_get_burst(chan, src_best_burst); + if (src_burst_size < 0) + return src_burst_size; + + dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_DEV) | + FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, dst_bus_width) | + FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, src_bus_width) | + FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dst_burst_size) | + FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, src_burst_size); + + /* Set FIFO threshold */ + chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK; + if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE) + chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth); + + /* Set peripheral address */ + chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr; + *buswidth = dst_addr_width; + break; + + case DMA_DEV_TO_MEM: + /* Set device data size */ + src_bus_width = stm32_dma_get_width(chan, src_addr_width); + if (src_bus_width < 0) + return src_bus_width; + + /* Set device burst size */ + src_best_burst = stm32_dma_get_best_burst(buf_len, + src_maxburst, + fifoth, + src_addr_width); + chan->mem_burst = src_best_burst; + src_burst_size = stm32_dma_get_burst(chan, src_best_burst); + if (src_burst_size < 0) + return src_burst_size; + + /* Set memory data size */ + dst_addr_width = stm32_dma_get_max_width(buf_len, buf_addr, + fifoth); + chan->mem_width = dst_addr_width; + dst_bus_width = stm32_dma_get_width(chan, dst_addr_width); + if (dst_bus_width < 0) + return dst_bus_width; + + /* + * Set memory burst size - burst not possible if address is not aligned on + * the address boundary equal to the size of the transfer + */ + if (buf_addr & (buf_len - 1)) + dst_maxburst = 1; + else + dst_maxburst = STM32_DMA_MAX_BURST; + dst_best_burst = stm32_dma_get_best_burst(buf_len, + dst_maxburst, + fifoth, + dst_addr_width); + chan->mem_burst = dst_best_burst; + dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst); + if (dst_burst_size < 0) + return dst_burst_size; + + dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_DEV_TO_MEM) | + FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, src_bus_width) | + FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, dst_bus_width) | + FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, src_burst_size) | + FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dst_burst_size); + + /* Set FIFO threshold */ + chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK; + if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE) + chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth); + + /* Set peripheral address */ + chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr; + *buswidth = chan->dma_sconfig.src_addr_width; + break; + + default: + dev_err(chan2dev(chan), "Dma direction is not supported\n"); + return -EINVAL; + } + + stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst); + + /* Set DMA control register */ + chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK | + STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK | + STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK); + chan->chan_reg.dma_scr |= dma_scr; + + return 0; +} + +static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs) +{ + memset(regs, 0, sizeof(struct stm32_dma_chan_reg)); +} + +static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( + struct dma_chan *c, struct scatterlist *sgl, + u32 sg_len, enum dma_transfer_direction direction, + unsigned long flags, void *context) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct stm32_dma_desc *desc; + struct scatterlist *sg; + enum dma_slave_buswidth buswidth; + u32 nb_data_items; + int i, ret; + + if (!chan->config_init) { + dev_err(chan2dev(chan), "dma channel is not configured\n"); + return NULL; + } + + if (sg_len < 1) { + dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len); + return NULL; + } + + desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT); + if (!desc) + return NULL; + + /* Set peripheral flow controller */ + if (chan->dma_sconfig.device_fc) + chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL; + else + chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL; + + /* Activate Double Buffer Mode if DMA triggers STM32 MDMA and more than 1 sg */ + if (chan->trig_mdma && sg_len > 1) { + chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM; + chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_CT; + } + + for_each_sg(sgl, sg, sg_len, i) { + ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, + sg_dma_len(sg), + sg_dma_address(sg)); + if (ret < 0) + goto err; + + desc->sg_req[i].len = sg_dma_len(sg); + + nb_data_items = desc->sg_req[i].len / buswidth; + if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) { + dev_err(chan2dev(chan), "nb items not supported\n"); + goto err; + } + + stm32_dma_clear_reg(&desc->sg_req[i].chan_reg); + desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr; + desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr; + desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar; + desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg); + desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg); + if (chan->trig_mdma) + desc->sg_req[i].chan_reg.dma_sm1ar += sg_dma_len(sg); + desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items; + } + + desc->num_sgs = sg_len; + desc->cyclic = false; + + return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); + +err: + kfree(desc); + return NULL; +} + +static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( + struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len, + size_t period_len, enum dma_transfer_direction direction, + unsigned long flags) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct stm32_dma_desc *desc; + enum dma_slave_buswidth buswidth; + u32 num_periods, nb_data_items; + int i, ret; + + if (!buf_len || !period_len) { + dev_err(chan2dev(chan), "Invalid buffer/period len\n"); + return NULL; + } + + if (!chan->config_init) { + dev_err(chan2dev(chan), "dma channel is not configured\n"); + return NULL; + } + + if (buf_len % period_len) { + dev_err(chan2dev(chan), "buf_len not multiple of period_len\n"); + return NULL; + } + + /* + * We allow to take more number of requests till DMA is + * not started. The driver will loop over all requests. + * Once DMA is started then new requests can be queued only after + * terminating the DMA. + */ + if (chan->busy) { + dev_err(chan2dev(chan), "Request not allowed when dma busy\n"); + return NULL; + } + + ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len, + buf_addr); + if (ret < 0) + return NULL; + + nb_data_items = period_len / buswidth; + if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) { + dev_err(chan2dev(chan), "number of items not supported\n"); + return NULL; + } + + /* Enable Circular mode or double buffer mode */ + if (buf_len == period_len) { + chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC; + } else { + chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM; + chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_CT; + } + + /* Clear periph ctrl if client set it */ + chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL; + + num_periods = buf_len / period_len; + + desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT); + if (!desc) + return NULL; + + for (i = 0; i < num_periods; i++) { + desc->sg_req[i].len = period_len; + + stm32_dma_clear_reg(&desc->sg_req[i].chan_reg); + desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr; + desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr; + desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar; + desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr; + desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr; + if (chan->trig_mdma) + desc->sg_req[i].chan_reg.dma_sm1ar += period_len; + desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items; + if (!chan->trig_mdma) + buf_addr += period_len; + } + + desc->num_sgs = num_periods; + desc->cyclic = true; + + return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); +} + +static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( + struct dma_chan *c, dma_addr_t dest, + dma_addr_t src, size_t len, unsigned long flags) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + enum dma_slave_buswidth max_width; + struct stm32_dma_desc *desc; + size_t xfer_count, offset; + u32 num_sgs, best_burst, threshold; + int dma_burst, i; + + num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS); + desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT); + if (!desc) + return NULL; + + threshold = chan->threshold; + + for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) { + xfer_count = min_t(size_t, len - offset, + STM32_DMA_ALIGNED_MAX_DATA_ITEMS); + + /* Compute best burst size */ + max_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST, + threshold, max_width); + dma_burst = stm32_dma_get_burst(chan, best_burst); + if (dma_burst < 0) { + kfree(desc); + return NULL; + } + + stm32_dma_clear_reg(&desc->sg_req[i].chan_reg); + desc->sg_req[i].chan_reg.dma_scr = + FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_MEM) | + FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dma_burst) | + FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dma_burst) | + STM32_DMA_SCR_MINC | + STM32_DMA_SCR_PINC | + STM32_DMA_SCR_TCIE | + STM32_DMA_SCR_TEIE; + desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK; + desc->sg_req[i].chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, threshold); + desc->sg_req[i].chan_reg.dma_spar = src + offset; + desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset; + desc->sg_req[i].chan_reg.dma_sndtr = xfer_count; + desc->sg_req[i].len = xfer_count; + } + + desc->num_sgs = num_sgs; + desc->cyclic = false; + + return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); +} + +static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan) +{ + u32 dma_scr, width, ndtr; + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id)); + width = FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, dma_scr); + ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id)); + + return ndtr << width; +} + +/** + * stm32_dma_is_current_sg - check that expected sg_req is currently transferred + * @chan: dma channel + * + * This function called when IRQ are disable, checks that the hardware has not + * switched on the next transfer in double buffer mode. The test is done by + * comparing the next_sg memory address with the hardware related register + * (based on CT bit value). + * + * Returns true if expected current transfer is still running or double + * buffer mode is not activated. + */ +static bool stm32_dma_is_current_sg(struct stm32_dma_chan *chan) +{ + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + struct stm32_dma_sg_req *sg_req; + u32 dma_scr, dma_smar, id, period_len; + + id = chan->id; + dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + + /* In cyclic CIRC but not DBM, CT is not used */ + if (!(dma_scr & STM32_DMA_SCR_DBM)) + return true; + + sg_req = &chan->desc->sg_req[chan->next_sg]; + period_len = sg_req->len; + + /* DBM - take care of a previous pause/resume not yet post reconfigured */ + if (dma_scr & STM32_DMA_SCR_CT) { + dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)); + /* + * If transfer has been pause/resumed, + * SM0AR is in the range of [SM0AR:SM0AR+period_len] + */ + return (dma_smar >= sg_req->chan_reg.dma_sm0ar && + dma_smar < sg_req->chan_reg.dma_sm0ar + period_len); + } + + dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)); + /* + * If transfer has been pause/resumed, + * SM1AR is in the range of [SM1AR:SM1AR+period_len] + */ + return (dma_smar >= sg_req->chan_reg.dma_sm1ar && + dma_smar < sg_req->chan_reg.dma_sm1ar + period_len); +} + +static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan, + struct stm32_dma_desc *desc, + u32 next_sg) +{ + u32 modulo, burst_size; + u32 residue; + u32 n_sg = next_sg; + struct stm32_dma_sg_req *sg_req = &chan->desc->sg_req[chan->next_sg]; + int i; + + /* + * Calculate the residue means compute the descriptors + * information: + * - the sg_req currently transferred + * - the Hardware remaining position in this sg (NDTR bits field). + * + * A race condition may occur if DMA is running in cyclic or double + * buffer mode, since the DMA register are automatically reloaded at end + * of period transfer. The hardware may have switched to the next + * transfer (CT bit updated) just before the position (SxNDTR reg) is + * read. + * In this case the SxNDTR reg could (or not) correspond to the new + * transfer position, and not the expected one. + * The strategy implemented in the stm32 driver is to: + * - read the SxNDTR register + * - crosscheck that hardware is still in current transfer. + * In case of switch, we can assume that the DMA is at the beginning of + * the next transfer. So we approximate the residue in consequence, by + * pointing on the beginning of next transfer. + * + * This race condition doesn't apply for none cyclic mode, as double + * buffer is not used. In such situation registers are updated by the + * software. + */ + + residue = stm32_dma_get_remaining_bytes(chan); + + if ((chan->desc->cyclic || chan->trig_mdma) && !stm32_dma_is_current_sg(chan)) { + n_sg++; + if (n_sg == chan->desc->num_sgs) + n_sg = 0; + if (!chan->trig_mdma) + residue = sg_req->len; + } + + /* + * In cyclic mode, for the last period, residue = remaining bytes + * from NDTR, + * else for all other periods in cyclic mode, and in sg mode, + * residue = remaining bytes from NDTR + remaining + * periods/sg to be transferred + */ + if ((!chan->desc->cyclic && !chan->trig_mdma) || n_sg != 0) + for (i = n_sg; i < desc->num_sgs; i++) + residue += desc->sg_req[i].len; + + if (!chan->mem_burst) + return residue; + + burst_size = chan->mem_burst * chan->mem_width; + modulo = residue % burst_size; + if (modulo) + residue = residue - modulo + burst_size; + + return residue; +} + +static enum dma_status stm32_dma_tx_status(struct dma_chan *c, + dma_cookie_t cookie, + struct dma_tx_state *state) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct virt_dma_desc *vdesc; + enum dma_status status; + unsigned long flags; + u32 residue = 0; + + status = dma_cookie_status(c, cookie, state); + if (status == DMA_COMPLETE) + return status; + + status = chan->status; + + if (!state) + return status; + + spin_lock_irqsave(&chan->vchan.lock, flags); + vdesc = vchan_find_desc(&chan->vchan, cookie); + if (chan->desc && cookie == chan->desc->vdesc.tx.cookie) + residue = stm32_dma_desc_residue(chan, chan->desc, + chan->next_sg); + else if (vdesc) + residue = stm32_dma_desc_residue(chan, + to_stm32_dma_desc(vdesc), 0); + dma_set_residue(state, residue); + + spin_unlock_irqrestore(&chan->vchan.lock, flags); + + return status; +} + +static int stm32_dma_alloc_chan_resources(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + int ret; + + chan->config_init = false; + + ret = pm_runtime_resume_and_get(dmadev->ddev.dev); + if (ret < 0) + return ret; + + ret = stm32_dma_disable_chan(chan); + if (ret < 0) + pm_runtime_put(dmadev->ddev.dev); + + return ret; +} + +static void stm32_dma_free_chan_resources(struct dma_chan *c) +{ + struct stm32_dma_chan *chan = to_stm32_dma_chan(c); + struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); + unsigned long flags; + + dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id); + + if (chan->busy) { + spin_lock_irqsave(&chan->vchan.lock, flags); + stm32_dma_stop(chan); + chan->desc = NULL; + spin_unlock_irqrestore(&chan->vchan.lock, flags); + } + + pm_runtime_put(dmadev->ddev.dev); + + vchan_free_chan_resources(to_virt_chan(c)); + stm32_dma_clear_reg(&chan->chan_reg); + chan->threshold = 0; +} + +static void stm32_dma_desc_free(struct virt_dma_desc *vdesc) +{ + kfree(container_of(vdesc, struct stm32_dma_desc, vdesc)); +} + +static void stm32_dma_set_config(struct stm32_dma_chan *chan, + struct stm32_dma_cfg *cfg) +{ + stm32_dma_clear_reg(&chan->chan_reg); + + chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK; + chan->chan_reg.dma_scr |= FIELD_PREP(STM32_DMA_SCR_REQ_MASK, cfg->request_line); + + /* Enable Interrupts */ + chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE; + + chan->threshold = FIELD_GET(STM32_DMA_THRESHOLD_FTR_MASK, cfg->features); + if (FIELD_GET(STM32_DMA_DIRECT_MODE_MASK, cfg->features)) + chan->threshold = STM32_DMA_FIFO_THRESHOLD_NONE; + if (FIELD_GET(STM32_DMA_ALT_ACK_MODE_MASK, cfg->features)) + chan->chan_reg.dma_scr |= STM32_DMA_SCR_TRBUFF; + chan->mdma_config.stream_id = FIELD_GET(STM32_DMA_MDMA_STREAM_ID_MASK, cfg->features); +} + +static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec, + struct of_dma *ofdma) +{ + struct stm32_dma_device *dmadev = ofdma->of_dma_data; + struct device *dev = dmadev->ddev.dev; + struct stm32_dma_cfg cfg; + struct stm32_dma_chan *chan; + struct dma_chan *c; + + if (dma_spec->args_count < 4) { + dev_err(dev, "Bad number of cells\n"); + return NULL; + } + + cfg.channel_id = dma_spec->args[0]; + cfg.request_line = dma_spec->args[1]; + cfg.stream_config = dma_spec->args[2]; + cfg.features = dma_spec->args[3]; + + if (cfg.channel_id >= STM32_DMA_MAX_CHANNELS || + cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) { + dev_err(dev, "Bad channel and/or request id\n"); + return NULL; + } + + chan = &dmadev->chan[cfg.channel_id]; + + c = dma_get_slave_channel(&chan->vchan.chan); + if (!c) { + dev_err(dev, "No more channels available\n"); + return NULL; + } + + stm32_dma_set_config(chan, &cfg); + + return c; +} + +static const struct of_device_id stm32_dma_of_match[] = { + { .compatible = "st,stm32-dma", }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, stm32_dma_of_match); + +static int stm32_dma_probe(struct platform_device *pdev) +{ + struct stm32_dma_chan *chan; + struct stm32_dma_device *dmadev; + struct dma_device *dd; + const struct of_device_id *match; + struct resource *res; + struct reset_control *rst; + int i, ret; + + match = of_match_device(stm32_dma_of_match, &pdev->dev); + if (!match) { + dev_err(&pdev->dev, "Error: No device match found\n"); + return -ENODEV; + } + + dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL); + if (!dmadev) + return -ENOMEM; + + dd = &dmadev->ddev; + + dmadev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(dmadev->base)) + return PTR_ERR(dmadev->base); + + dmadev->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(dmadev->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(dmadev->clk), "Can't get clock\n"); + + ret = clk_prepare_enable(dmadev->clk); + if (ret < 0) { + dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret); + return ret; + } + + dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node, + "st,mem2mem"); + + rst = devm_reset_control_get(&pdev->dev, NULL); + if (IS_ERR(rst)) { + ret = PTR_ERR(rst); + if (ret == -EPROBE_DEFER) + goto clk_free; + } else { + reset_control_assert(rst); + udelay(2); + reset_control_deassert(rst); + } + + dma_set_max_seg_size(&pdev->dev, STM32_DMA_ALIGNED_MAX_DATA_ITEMS); + + dma_cap_set(DMA_SLAVE, dd->cap_mask); + dma_cap_set(DMA_PRIVATE, dd->cap_mask); + dma_cap_set(DMA_CYCLIC, dd->cap_mask); + dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources; + dd->device_free_chan_resources = stm32_dma_free_chan_resources; + dd->device_tx_status = stm32_dma_tx_status; + dd->device_issue_pending = stm32_dma_issue_pending; + dd->device_prep_slave_sg = stm32_dma_prep_slave_sg; + dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic; + dd->device_config = stm32_dma_slave_config; + dd->device_pause = stm32_dma_pause; + dd->device_resume = stm32_dma_resume; + dd->device_terminate_all = stm32_dma_terminate_all; + dd->device_synchronize = stm32_dma_synchronize; + dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); + dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); + dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); + dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + dd->copy_align = DMAENGINE_ALIGN_32_BYTES; + dd->max_burst = STM32_DMA_MAX_BURST; + dd->max_sg_burst = STM32_DMA_ALIGNED_MAX_DATA_ITEMS; + dd->descriptor_reuse = true; + dd->dev = &pdev->dev; + INIT_LIST_HEAD(&dd->channels); + + if (dmadev->mem2mem) { + dma_cap_set(DMA_MEMCPY, dd->cap_mask); + dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy; + dd->directions |= BIT(DMA_MEM_TO_MEM); + } + + for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) { + chan = &dmadev->chan[i]; + chan->id = i; + chan->vchan.desc_free = stm32_dma_desc_free; + vchan_init(&chan->vchan, dd); + + chan->mdma_config.ifcr = res->start; + chan->mdma_config.ifcr += STM32_DMA_IFCR(chan->id); + + chan->mdma_config.tcf = STM32_DMA_TCI; + chan->mdma_config.tcf <<= STM32_DMA_FLAGS_SHIFT(chan->id); + } + + ret = dma_async_device_register(dd); + if (ret) + goto clk_free; + + for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) { + chan = &dmadev->chan[i]; + ret = platform_get_irq(pdev, i); + if (ret < 0) + goto err_unregister; + chan->irq = ret; + + ret = devm_request_irq(&pdev->dev, chan->irq, + stm32_dma_chan_irq, 0, + dev_name(chan2dev(chan)), chan); + if (ret) { + dev_err(&pdev->dev, + "request_irq failed with err %d channel %d\n", + ret, i); + goto err_unregister; + } + } + + ret = of_dma_controller_register(pdev->dev.of_node, + stm32_dma_of_xlate, dmadev); + if (ret < 0) { + dev_err(&pdev->dev, + "STM32 DMA DMA OF registration failed %d\n", ret); + goto err_unregister; + } + + platform_set_drvdata(pdev, dmadev); + + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + pm_runtime_get_noresume(&pdev->dev); + pm_runtime_put(&pdev->dev); + + dev_info(&pdev->dev, "STM32 DMA driver registered\n"); + + return 0; + +err_unregister: + dma_async_device_unregister(dd); +clk_free: + clk_disable_unprepare(dmadev->clk); + + return ret; +} + +#ifdef CONFIG_PM +static int stm32_dma_runtime_suspend(struct device *dev) +{ + struct stm32_dma_device *dmadev = dev_get_drvdata(dev); + + clk_disable_unprepare(dmadev->clk); + + return 0; +} + +static int stm32_dma_runtime_resume(struct device *dev) +{ + struct stm32_dma_device *dmadev = dev_get_drvdata(dev); + int ret; + + ret = clk_prepare_enable(dmadev->clk); + if (ret) { + dev_err(dev, "failed to prepare_enable clock\n"); + return ret; + } + + return 0; +} +#endif + +#ifdef CONFIG_PM_SLEEP +static int stm32_dma_pm_suspend(struct device *dev) +{ + struct stm32_dma_device *dmadev = dev_get_drvdata(dev); + int id, ret, scr; + + ret = pm_runtime_resume_and_get(dev); + if (ret < 0) + return ret; + + for (id = 0; id < STM32_DMA_MAX_CHANNELS; id++) { + scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + if (scr & STM32_DMA_SCR_EN) { + dev_warn(dev, "Suspend is prevented by Chan %i\n", id); + return -EBUSY; + } + } + + pm_runtime_put_sync(dev); + + pm_runtime_force_suspend(dev); + + return 0; +} + +static int stm32_dma_pm_resume(struct device *dev) +{ + return pm_runtime_force_resume(dev); +} +#endif + +static const struct dev_pm_ops stm32_dma_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(stm32_dma_pm_suspend, stm32_dma_pm_resume) + SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend, + stm32_dma_runtime_resume, NULL) +}; + +static struct platform_driver stm32_dma_driver = { + .driver = { + .name = "stm32-dma", + .of_match_table = stm32_dma_of_match, + .pm = &stm32_dma_pm_ops, + }, + .probe = stm32_dma_probe, +}; + +static int __init stm32_dma_init(void) +{ + return platform_driver_register(&stm32_dma_driver); +} +subsys_initcall(stm32_dma_init); |