diff options
Diffstat (limited to 'drivers/dma/bcm2835-dma.c')
| -rw-r--r-- | drivers/dma/bcm2835-dma.c | 1046 |
1 files changed, 1046 insertions, 0 deletions
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c new file mode 100644 index 0000000000..0807fb9eb2 --- /dev/null +++ b/drivers/dma/bcm2835-dma.c @@ -0,0 +1,1046 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * BCM2835 DMA engine support + * + * Author: Florian Meier <florian.meier@koalo.de> + * Copyright 2013 + * + * Based on + * OMAP DMAengine support by Russell King + * + * BCM2708 DMA Driver + * Copyright (C) 2010 Broadcom + * + * Raspberry Pi PCM I2S ALSA Driver + * Copyright (c) by Phil Poole 2013 + * + * MARVELL MMP Peripheral DMA Driver + * Copyright 2012 Marvell International Ltd. + */ +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/dmapool.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/spinlock.h> +#include <linux/of.h> +#include <linux/of_dma.h> + +#include "virt-dma.h" + +#define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14 +#define BCM2835_DMA_CHAN_NAME_SIZE 8 + +/** + * struct bcm2835_dmadev - BCM2835 DMA controller + * @ddev: DMA device + * @base: base address of register map + * @zero_page: bus address of zero page (to detect transactions copying from + * zero page and avoid accessing memory if so) + */ +struct bcm2835_dmadev { + struct dma_device ddev; + void __iomem *base; + dma_addr_t zero_page; +}; + +struct bcm2835_dma_cb { + uint32_t info; + uint32_t src; + uint32_t dst; + uint32_t length; + uint32_t stride; + uint32_t next; + uint32_t pad[2]; +}; + +struct bcm2835_cb_entry { + struct bcm2835_dma_cb *cb; + dma_addr_t paddr; +}; + +struct bcm2835_chan { + struct virt_dma_chan vc; + + struct dma_slave_config cfg; + unsigned int dreq; + + int ch; + struct bcm2835_desc *desc; + struct dma_pool *cb_pool; + + void __iomem *chan_base; + int irq_number; + unsigned int irq_flags; + + bool is_lite_channel; +}; + +struct bcm2835_desc { + struct bcm2835_chan *c; + struct virt_dma_desc vd; + enum dma_transfer_direction dir; + + unsigned int frames; + size_t size; + + bool cyclic; + + struct bcm2835_cb_entry cb_list[]; +}; + +#define BCM2835_DMA_CS 0x00 +#define BCM2835_DMA_ADDR 0x04 +#define BCM2835_DMA_TI 0x08 +#define BCM2835_DMA_SOURCE_AD 0x0c +#define BCM2835_DMA_DEST_AD 0x10 +#define BCM2835_DMA_LEN 0x14 +#define BCM2835_DMA_STRIDE 0x18 +#define BCM2835_DMA_NEXTCB 0x1c +#define BCM2835_DMA_DEBUG 0x20 + +/* DMA CS Control and Status bits */ +#define BCM2835_DMA_ACTIVE BIT(0) /* activate the DMA */ +#define BCM2835_DMA_END BIT(1) /* current CB has ended */ +#define BCM2835_DMA_INT BIT(2) /* interrupt status */ +#define BCM2835_DMA_DREQ BIT(3) /* DREQ state */ +#define BCM2835_DMA_ISPAUSED BIT(4) /* Pause requested or not active */ +#define BCM2835_DMA_ISHELD BIT(5) /* Is held by DREQ flow control */ +#define BCM2835_DMA_WAITING_FOR_WRITES BIT(6) /* waiting for last + * AXI-write to ack + */ +#define BCM2835_DMA_ERR BIT(8) +#define BCM2835_DMA_PRIORITY(x) ((x & 15) << 16) /* AXI priority */ +#define BCM2835_DMA_PANIC_PRIORITY(x) ((x & 15) << 20) /* panic priority */ +/* current value of TI.BCM2835_DMA_WAIT_RESP */ +#define BCM2835_DMA_WAIT_FOR_WRITES BIT(28) +#define BCM2835_DMA_DIS_DEBUG BIT(29) /* disable debug pause signal */ +#define BCM2835_DMA_ABORT BIT(30) /* Stop current CB, go to next, WO */ +#define BCM2835_DMA_RESET BIT(31) /* WO, self clearing */ + +/* Transfer information bits - also bcm2835_cb.info field */ +#define BCM2835_DMA_INT_EN BIT(0) +#define BCM2835_DMA_TDMODE BIT(1) /* 2D-Mode */ +#define BCM2835_DMA_WAIT_RESP BIT(3) /* wait for AXI-write to be acked */ +#define BCM2835_DMA_D_INC BIT(4) +#define BCM2835_DMA_D_WIDTH BIT(5) /* 128bit writes if set */ +#define BCM2835_DMA_D_DREQ BIT(6) /* enable DREQ for destination */ +#define BCM2835_DMA_D_IGNORE BIT(7) /* ignore destination writes */ +#define BCM2835_DMA_S_INC BIT(8) +#define BCM2835_DMA_S_WIDTH BIT(9) /* 128bit writes if set */ +#define BCM2835_DMA_S_DREQ BIT(10) /* enable SREQ for source */ +#define BCM2835_DMA_S_IGNORE BIT(11) /* ignore source reads - read 0 */ +#define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12) +#define BCM2835_DMA_PER_MAP(x) ((x & 31) << 16) /* REQ source */ +#define BCM2835_DMA_WAIT(x) ((x & 31) << 21) /* add DMA-wait cycles */ +#define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */ + +/* debug register bits */ +#define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR BIT(0) +#define BCM2835_DMA_DEBUG_FIFO_ERR BIT(1) +#define BCM2835_DMA_DEBUG_READ_ERR BIT(2) +#define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_SHIFT 4 +#define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_BITS 4 +#define BCM2835_DMA_DEBUG_ID_SHIFT 16 +#define BCM2835_DMA_DEBUG_ID_BITS 9 +#define BCM2835_DMA_DEBUG_STATE_SHIFT 16 +#define BCM2835_DMA_DEBUG_STATE_BITS 9 +#define BCM2835_DMA_DEBUG_VERSION_SHIFT 25 +#define BCM2835_DMA_DEBUG_VERSION_BITS 3 +#define BCM2835_DMA_DEBUG_LITE BIT(28) + +/* shared registers for all dma channels */ +#define BCM2835_DMA_INT_STATUS 0xfe0 +#define BCM2835_DMA_ENABLE 0xff0 + +#define BCM2835_DMA_DATA_TYPE_S8 1 +#define BCM2835_DMA_DATA_TYPE_S16 2 +#define BCM2835_DMA_DATA_TYPE_S32 4 +#define BCM2835_DMA_DATA_TYPE_S128 16 + +/* Valid only for channels 0 - 14, 15 has its own base address */ +#define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */ +#define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n)) + +/* the max dma length for different channels */ +#define MAX_DMA_LEN SZ_1G +#define MAX_LITE_DMA_LEN (SZ_64K - 4) + +static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c) +{ + /* lite and normal channels have different max frame length */ + return c->is_lite_channel ? MAX_LITE_DMA_LEN : MAX_DMA_LEN; +} + +/* how many frames of max_len size do we need to transfer len bytes */ +static inline size_t bcm2835_dma_frames_for_length(size_t len, + size_t max_len) +{ + return DIV_ROUND_UP(len, max_len); +} + +static inline struct bcm2835_dmadev *to_bcm2835_dma_dev(struct dma_device *d) +{ + return container_of(d, struct bcm2835_dmadev, ddev); +} + +static inline struct bcm2835_chan *to_bcm2835_dma_chan(struct dma_chan *c) +{ + return container_of(c, struct bcm2835_chan, vc.chan); +} + +static inline struct bcm2835_desc *to_bcm2835_dma_desc( + struct dma_async_tx_descriptor *t) +{ + return container_of(t, struct bcm2835_desc, vd.tx); +} + +static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc) +{ + size_t i; + + for (i = 0; i < desc->frames; i++) + dma_pool_free(desc->c->cb_pool, desc->cb_list[i].cb, + desc->cb_list[i].paddr); + + kfree(desc); +} + +static void bcm2835_dma_desc_free(struct virt_dma_desc *vd) +{ + bcm2835_dma_free_cb_chain( + container_of(vd, struct bcm2835_desc, vd)); +} + +static void bcm2835_dma_create_cb_set_length( + struct bcm2835_chan *chan, + struct bcm2835_dma_cb *control_block, + size_t len, + size_t period_len, + size_t *total_len, + u32 finalextrainfo) +{ + size_t max_len = bcm2835_dma_max_frame_length(chan); + + /* set the length taking lite-channel limitations into account */ + control_block->length = min_t(u32, len, max_len); + + /* finished if we have no period_length */ + if (!period_len) + return; + + /* + * period_len means: that we need to generate + * transfers that are terminating at every + * multiple of period_len - this is typically + * used to set the interrupt flag in info + * which is required during cyclic transfers + */ + + /* have we filled in period_length yet? */ + if (*total_len + control_block->length < period_len) { + /* update number of bytes in this period so far */ + *total_len += control_block->length; + return; + } + + /* calculate the length that remains to reach period_length */ + control_block->length = period_len - *total_len; + + /* reset total_length for next period */ + *total_len = 0; + + /* add extrainfo bits in info */ + control_block->info |= finalextrainfo; +} + +static inline size_t bcm2835_dma_count_frames_for_sg( + struct bcm2835_chan *c, + struct scatterlist *sgl, + unsigned int sg_len) +{ + size_t frames = 0; + struct scatterlist *sgent; + unsigned int i; + size_t plength = bcm2835_dma_max_frame_length(c); + + for_each_sg(sgl, sgent, sg_len, i) + frames += bcm2835_dma_frames_for_length( + sg_dma_len(sgent), plength); + + return frames; +} + +/** + * bcm2835_dma_create_cb_chain - create a control block and fills data in + * + * @chan: the @dma_chan for which we run this + * @direction: the direction in which we transfer + * @cyclic: it is a cyclic transfer + * @info: the default info bits to apply per controlblock + * @frames: number of controlblocks to allocate + * @src: the src address to assign (if the S_INC bit is set + * in @info, then it gets incremented) + * @dst: the dst address to assign (if the D_INC bit is set + * in @info, then it gets incremented) + * @buf_len: the full buffer length (may also be 0) + * @period_len: the period length when to apply @finalextrainfo + * in addition to the last transfer + * this will also break some control-blocks early + * @finalextrainfo: additional bits in last controlblock + * (or when period_len is reached in case of cyclic) + * @gfp: the GFP flag to use for allocation + */ +static struct bcm2835_desc *bcm2835_dma_create_cb_chain( + struct dma_chan *chan, enum dma_transfer_direction direction, + bool cyclic, u32 info, u32 finalextrainfo, size_t frames, + dma_addr_t src, dma_addr_t dst, size_t buf_len, + size_t period_len, gfp_t gfp) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + size_t len = buf_len, total_len; + size_t frame; + struct bcm2835_desc *d; + struct bcm2835_cb_entry *cb_entry; + struct bcm2835_dma_cb *control_block; + + if (!frames) + return NULL; + + /* allocate and setup the descriptor. */ + d = kzalloc(struct_size(d, cb_list, frames), gfp); + if (!d) + return NULL; + + d->c = c; + d->dir = direction; + d->cyclic = cyclic; + + /* + * Iterate over all frames, create a control block + * for each frame and link them together. + */ + for (frame = 0, total_len = 0; frame < frames; d->frames++, frame++) { + cb_entry = &d->cb_list[frame]; + cb_entry->cb = dma_pool_alloc(c->cb_pool, gfp, + &cb_entry->paddr); + if (!cb_entry->cb) + goto error_cb; + + /* fill in the control block */ + control_block = cb_entry->cb; + control_block->info = info; + control_block->src = src; + control_block->dst = dst; + control_block->stride = 0; + control_block->next = 0; + /* set up length in control_block if requested */ + if (buf_len) { + /* calculate length honoring period_length */ + bcm2835_dma_create_cb_set_length( + c, control_block, + len, period_len, &total_len, + cyclic ? finalextrainfo : 0); + + /* calculate new remaining length */ + len -= control_block->length; + } + + /* link this the last controlblock */ + if (frame) + d->cb_list[frame - 1].cb->next = cb_entry->paddr; + + /* update src and dst and length */ + if (src && (info & BCM2835_DMA_S_INC)) + src += control_block->length; + if (dst && (info & BCM2835_DMA_D_INC)) + dst += control_block->length; + + /* Length of total transfer */ + d->size += control_block->length; + } + + /* the last frame requires extra flags */ + d->cb_list[d->frames - 1].cb->info |= finalextrainfo; + + /* detect a size missmatch */ + if (buf_len && (d->size != buf_len)) + goto error_cb; + + return d; +error_cb: + bcm2835_dma_free_cb_chain(d); + + return NULL; +} + +static void bcm2835_dma_fill_cb_chain_with_sg( + struct dma_chan *chan, + enum dma_transfer_direction direction, + struct bcm2835_cb_entry *cb, + struct scatterlist *sgl, + unsigned int sg_len) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + size_t len, max_len; + unsigned int i; + dma_addr_t addr; + struct scatterlist *sgent; + + max_len = bcm2835_dma_max_frame_length(c); + for_each_sg(sgl, sgent, sg_len, i) { + for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent); + len > 0; + addr += cb->cb->length, len -= cb->cb->length, cb++) { + if (direction == DMA_DEV_TO_MEM) + cb->cb->dst = addr; + else + cb->cb->src = addr; + cb->cb->length = min(len, max_len); + } + } +} + +static void bcm2835_dma_abort(struct bcm2835_chan *c) +{ + void __iomem *chan_base = c->chan_base; + long int timeout = 10000; + + /* + * A zero control block address means the channel is idle. + * (The ACTIVE flag in the CS register is not a reliable indicator.) + */ + if (!readl(chan_base + BCM2835_DMA_ADDR)) + return; + + /* Write 0 to the active bit - Pause the DMA */ + writel(0, chan_base + BCM2835_DMA_CS); + + /* Wait for any current AXI transfer to complete */ + while ((readl(chan_base + BCM2835_DMA_CS) & + BCM2835_DMA_WAITING_FOR_WRITES) && --timeout) + cpu_relax(); + + /* Peripheral might be stuck and fail to signal AXI write responses */ + if (!timeout) + dev_err(c->vc.chan.device->dev, + "failed to complete outstanding writes\n"); + + writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS); +} + +static void bcm2835_dma_start_desc(struct bcm2835_chan *c) +{ + struct virt_dma_desc *vd = vchan_next_desc(&c->vc); + struct bcm2835_desc *d; + + if (!vd) { + c->desc = NULL; + return; + } + + list_del(&vd->node); + + c->desc = d = to_bcm2835_dma_desc(&vd->tx); + + writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR); + writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS); +} + +static irqreturn_t bcm2835_dma_callback(int irq, void *data) +{ + struct bcm2835_chan *c = data; + struct bcm2835_desc *d; + unsigned long flags; + + /* check the shared interrupt */ + if (c->irq_flags & IRQF_SHARED) { + /* check if the interrupt is enabled */ + flags = readl(c->chan_base + BCM2835_DMA_CS); + /* if not set then we are not the reason for the irq */ + if (!(flags & BCM2835_DMA_INT)) + return IRQ_NONE; + } + + spin_lock_irqsave(&c->vc.lock, flags); + + /* + * Clear the INT flag to receive further interrupts. Keep the channel + * active in case the descriptor is cyclic or in case the client has + * already terminated the descriptor and issued a new one. (May happen + * if this IRQ handler is threaded.) If the channel is finished, it + * will remain idle despite the ACTIVE flag being set. + */ + writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE, + c->chan_base + BCM2835_DMA_CS); + + d = c->desc; + + if (d) { + if (d->cyclic) { + /* call the cyclic callback */ + vchan_cyclic_callback(&d->vd); + } else if (!readl(c->chan_base + BCM2835_DMA_ADDR)) { + vchan_cookie_complete(&c->desc->vd); + bcm2835_dma_start_desc(c); + } + } + + spin_unlock_irqrestore(&c->vc.lock, flags); + + return IRQ_HANDLED; +} + +static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct device *dev = c->vc.chan.device->dev; + + dev_dbg(dev, "Allocating DMA channel %d\n", c->ch); + + /* + * Control blocks are 256 bit in length and must start at a 256 bit + * (32 byte) aligned address (BCM2835 ARM Peripherals, sec. 4.2.1.1). + */ + c->cb_pool = dma_pool_create(dev_name(dev), dev, + sizeof(struct bcm2835_dma_cb), 32, 0); + if (!c->cb_pool) { + dev_err(dev, "unable to allocate descriptor pool\n"); + return -ENOMEM; + } + + return request_irq(c->irq_number, bcm2835_dma_callback, + c->irq_flags, "DMA IRQ", c); +} + +static void bcm2835_dma_free_chan_resources(struct dma_chan *chan) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + + vchan_free_chan_resources(&c->vc); + free_irq(c->irq_number, c); + dma_pool_destroy(c->cb_pool); + + dev_dbg(c->vc.chan.device->dev, "Freeing DMA channel %u\n", c->ch); +} + +static size_t bcm2835_dma_desc_size(struct bcm2835_desc *d) +{ + return d->size; +} + +static size_t bcm2835_dma_desc_size_pos(struct bcm2835_desc *d, dma_addr_t addr) +{ + unsigned int i; + size_t size; + + for (size = i = 0; i < d->frames; i++) { + struct bcm2835_dma_cb *control_block = d->cb_list[i].cb; + size_t this_size = control_block->length; + dma_addr_t dma; + + if (d->dir == DMA_DEV_TO_MEM) + dma = control_block->dst; + else + dma = control_block->src; + + if (size) + size += this_size; + else if (addr >= dma && addr < dma + this_size) + size += dma + this_size - addr; + } + + return size; +} + +static enum dma_status bcm2835_dma_tx_status(struct dma_chan *chan, + dma_cookie_t cookie, struct dma_tx_state *txstate) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct virt_dma_desc *vd; + enum dma_status ret; + unsigned long flags; + + ret = dma_cookie_status(chan, cookie, txstate); + if (ret == DMA_COMPLETE || !txstate) + return ret; + + spin_lock_irqsave(&c->vc.lock, flags); + vd = vchan_find_desc(&c->vc, cookie); + if (vd) { + txstate->residue = + bcm2835_dma_desc_size(to_bcm2835_dma_desc(&vd->tx)); + } else if (c->desc && c->desc->vd.tx.cookie == cookie) { + struct bcm2835_desc *d = c->desc; + dma_addr_t pos; + + if (d->dir == DMA_MEM_TO_DEV) + pos = readl(c->chan_base + BCM2835_DMA_SOURCE_AD); + else if (d->dir == DMA_DEV_TO_MEM) + pos = readl(c->chan_base + BCM2835_DMA_DEST_AD); + else + pos = 0; + + txstate->residue = bcm2835_dma_desc_size_pos(d, pos); + } else { + txstate->residue = 0; + } + + spin_unlock_irqrestore(&c->vc.lock, flags); + + return ret; +} + +static void bcm2835_dma_issue_pending(struct dma_chan *chan) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + unsigned long flags; + + spin_lock_irqsave(&c->vc.lock, flags); + if (vchan_issue_pending(&c->vc) && !c->desc) + bcm2835_dma_start_desc(c); + + spin_unlock_irqrestore(&c->vc.lock, flags); +} + +static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy( + struct dma_chan *chan, dma_addr_t dst, dma_addr_t src, + size_t len, unsigned long flags) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct bcm2835_desc *d; + u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC; + u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP; + size_t max_len = bcm2835_dma_max_frame_length(c); + size_t frames; + + /* if src, dst or len is not given return with an error */ + if (!src || !dst || !len) + return NULL; + + /* calculate number of frames */ + frames = bcm2835_dma_frames_for_length(len, max_len); + + /* allocate the CB chain - this also fills in the pointers */ + d = bcm2835_dma_create_cb_chain(chan, DMA_MEM_TO_MEM, false, + info, extra, frames, + src, dst, len, 0, GFP_KERNEL); + if (!d) + return NULL; + + return vchan_tx_prep(&c->vc, &d->vd, flags); +} + +static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg( + struct dma_chan *chan, + struct scatterlist *sgl, unsigned int sg_len, + enum dma_transfer_direction direction, + unsigned long flags, void *context) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct bcm2835_desc *d; + dma_addr_t src = 0, dst = 0; + u32 info = BCM2835_DMA_WAIT_RESP; + u32 extra = BCM2835_DMA_INT_EN; + size_t frames; + + if (!is_slave_direction(direction)) { + dev_err(chan->device->dev, + "%s: bad direction?\n", __func__); + return NULL; + } + + if (c->dreq != 0) + info |= BCM2835_DMA_PER_MAP(c->dreq); + + if (direction == DMA_DEV_TO_MEM) { + if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + src = c->cfg.src_addr; + info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC; + } else { + if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + dst = c->cfg.dst_addr; + info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC; + } + + /* count frames in sg list */ + frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len); + + /* allocate the CB chain */ + d = bcm2835_dma_create_cb_chain(chan, direction, false, + info, extra, + frames, src, dst, 0, 0, + GFP_NOWAIT); + if (!d) + return NULL; + + /* fill in frames with scatterlist pointers */ + bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list, + sgl, sg_len); + + return vchan_tx_prep(&c->vc, &d->vd, flags); +} + +static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( + struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, + size_t period_len, enum dma_transfer_direction direction, + unsigned long flags) +{ + struct bcm2835_dmadev *od = to_bcm2835_dma_dev(chan->device); + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct bcm2835_desc *d; + dma_addr_t src, dst; + u32 info = BCM2835_DMA_WAIT_RESP; + u32 extra = 0; + size_t max_len = bcm2835_dma_max_frame_length(c); + size_t frames; + + /* Grab configuration */ + if (!is_slave_direction(direction)) { + dev_err(chan->device->dev, "%s: bad direction?\n", __func__); + return NULL; + } + + if (!buf_len) { + dev_err(chan->device->dev, + "%s: bad buffer length (= 0)\n", __func__); + return NULL; + } + + if (flags & DMA_PREP_INTERRUPT) + extra |= BCM2835_DMA_INT_EN; + else + period_len = buf_len; + + /* + * warn if buf_len is not a multiple of period_len - this may leed + * to unexpected latencies for interrupts and thus audiable clicks + */ + if (buf_len % period_len) + dev_warn_once(chan->device->dev, + "%s: buffer_length (%zd) is not a multiple of period_len (%zd)\n", + __func__, buf_len, period_len); + + /* Setup DREQ channel */ + if (c->dreq != 0) + info |= BCM2835_DMA_PER_MAP(c->dreq); + + if (direction == DMA_DEV_TO_MEM) { + if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + src = c->cfg.src_addr; + dst = buf_addr; + info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC; + } else { + if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + dst = c->cfg.dst_addr; + src = buf_addr; + info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC; + + /* non-lite channels can write zeroes w/o accessing memory */ + if (buf_addr == od->zero_page && !c->is_lite_channel) + info |= BCM2835_DMA_S_IGNORE; + } + + /* calculate number of frames */ + frames = /* number of periods */ + DIV_ROUND_UP(buf_len, period_len) * + /* number of frames per period */ + bcm2835_dma_frames_for_length(period_len, max_len); + + /* + * allocate the CB chain + * note that we need to use GFP_NOWAIT, as the ALSA i2s dmaengine + * implementation calls prep_dma_cyclic with interrupts disabled. + */ + d = bcm2835_dma_create_cb_chain(chan, direction, true, + info, extra, + frames, src, dst, buf_len, + period_len, GFP_NOWAIT); + if (!d) + return NULL; + + /* wrap around into a loop */ + d->cb_list[d->frames - 1].cb->next = d->cb_list[0].paddr; + + return vchan_tx_prep(&c->vc, &d->vd, flags); +} + +static int bcm2835_dma_slave_config(struct dma_chan *chan, + struct dma_slave_config *cfg) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + + c->cfg = *cfg; + + return 0; +} + +static int bcm2835_dma_terminate_all(struct dma_chan *chan) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + unsigned long flags; + LIST_HEAD(head); + + spin_lock_irqsave(&c->vc.lock, flags); + + /* stop DMA activity */ + if (c->desc) { + vchan_terminate_vdesc(&c->desc->vd); + c->desc = NULL; + bcm2835_dma_abort(c); + } + + vchan_get_all_descriptors(&c->vc, &head); + spin_unlock_irqrestore(&c->vc.lock, flags); + vchan_dma_desc_free_list(&c->vc, &head); + + return 0; +} + +static void bcm2835_dma_synchronize(struct dma_chan *chan) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + + vchan_synchronize(&c->vc); +} + +static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, + int irq, unsigned int irq_flags) +{ + struct bcm2835_chan *c; + + c = devm_kzalloc(d->ddev.dev, sizeof(*c), GFP_KERNEL); + if (!c) + return -ENOMEM; + + c->vc.desc_free = bcm2835_dma_desc_free; + vchan_init(&c->vc, &d->ddev); + + c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id); + c->ch = chan_id; + c->irq_number = irq; + c->irq_flags = irq_flags; + + /* check in DEBUG register if this is a LITE channel */ + if (readl(c->chan_base + BCM2835_DMA_DEBUG) & + BCM2835_DMA_DEBUG_LITE) + c->is_lite_channel = true; + + return 0; +} + +static void bcm2835_dma_free(struct bcm2835_dmadev *od) +{ + struct bcm2835_chan *c, *next; + + list_for_each_entry_safe(c, next, &od->ddev.channels, + vc.chan.device_node) { + list_del(&c->vc.chan.device_node); + tasklet_kill(&c->vc.task); + } + + dma_unmap_page_attrs(od->ddev.dev, od->zero_page, PAGE_SIZE, + DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); +} + +static const struct of_device_id bcm2835_dma_of_match[] = { + { .compatible = "brcm,bcm2835-dma", }, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm2835_dma_of_match); + +static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec, + struct of_dma *ofdma) +{ + struct bcm2835_dmadev *d = ofdma->of_dma_data; + struct dma_chan *chan; + + chan = dma_get_any_slave_channel(&d->ddev); + if (!chan) + return NULL; + + /* Set DREQ from param */ + to_bcm2835_dma_chan(chan)->dreq = spec->args[0]; + + return chan; +} + +static int bcm2835_dma_probe(struct platform_device *pdev) +{ + struct bcm2835_dmadev *od; + void __iomem *base; + int rc; + int i, j; + int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1]; + int irq_flags; + uint32_t chans_available; + char chan_name[BCM2835_DMA_CHAN_NAME_SIZE]; + + if (!pdev->dev.dma_mask) + pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; + + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); + if (rc) { + dev_err(&pdev->dev, "Unable to set DMA mask\n"); + return rc; + } + + od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL); + if (!od) + return -ENOMEM; + + dma_set_max_seg_size(&pdev->dev, 0x3FFFFFFF); + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(base); + + od->base = base; + + dma_cap_set(DMA_SLAVE, od->ddev.cap_mask); + dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask); + dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask); + dma_cap_set(DMA_MEMCPY, od->ddev.cap_mask); + od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources; + od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources; + od->ddev.device_tx_status = bcm2835_dma_tx_status; + od->ddev.device_issue_pending = bcm2835_dma_issue_pending; + od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic; + od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg; + od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy; + od->ddev.device_config = bcm2835_dma_slave_config; + od->ddev.device_terminate_all = bcm2835_dma_terminate_all; + od->ddev.device_synchronize = bcm2835_dma_synchronize; + od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); + od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); + od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) | + BIT(DMA_MEM_TO_MEM); + od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + od->ddev.descriptor_reuse = true; + od->ddev.dev = &pdev->dev; + INIT_LIST_HEAD(&od->ddev.channels); + + platform_set_drvdata(pdev, od); + + od->zero_page = dma_map_page_attrs(od->ddev.dev, ZERO_PAGE(0), 0, + PAGE_SIZE, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); + if (dma_mapping_error(od->ddev.dev, od->zero_page)) { + dev_err(&pdev->dev, "Failed to map zero page\n"); + return -ENOMEM; + } + + /* Request DMA channel mask from device tree */ + if (of_property_read_u32(pdev->dev.of_node, + "brcm,dma-channel-mask", + &chans_available)) { + dev_err(&pdev->dev, "Failed to get channel mask\n"); + rc = -EINVAL; + goto err_no_dma; + } + + /* get irqs for each channel that we support */ + for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) { + /* skip masked out channels */ + if (!(chans_available & (1 << i))) { + irq[i] = -1; + continue; + } + + /* get the named irq */ + snprintf(chan_name, sizeof(chan_name), "dma%i", i); + irq[i] = platform_get_irq_byname(pdev, chan_name); + if (irq[i] >= 0) + continue; + + /* legacy device tree case handling */ + dev_warn_once(&pdev->dev, + "missing interrupt-names property in device tree - legacy interpretation is used\n"); + /* + * in case of channel >= 11 + * use the 11th interrupt and that is shared + */ + irq[i] = platform_get_irq(pdev, i < 11 ? i : 11); + } + + /* get irqs for each channel */ + for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) { + /* skip channels without irq */ + if (irq[i] < 0) + continue; + + /* check if there are other channels that also use this irq */ + irq_flags = 0; + for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++) + if ((i != j) && (irq[j] == irq[i])) { + irq_flags = IRQF_SHARED; + break; + } + + /* initialize the channel */ + rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags); + if (rc) + goto err_no_dma; + } + + dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i); + + /* Device-tree DMA controller registration */ + rc = of_dma_controller_register(pdev->dev.of_node, + bcm2835_dma_xlate, od); + if (rc) { + dev_err(&pdev->dev, "Failed to register DMA controller\n"); + goto err_no_dma; + } + + rc = dma_async_device_register(&od->ddev); + if (rc) { + dev_err(&pdev->dev, + "Failed to register slave DMA engine device: %d\n", rc); + goto err_no_dma; + } + + dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n"); + + return 0; + +err_no_dma: + bcm2835_dma_free(od); + return rc; +} + +static int bcm2835_dma_remove(struct platform_device *pdev) +{ + struct bcm2835_dmadev *od = platform_get_drvdata(pdev); + + dma_async_device_unregister(&od->ddev); + bcm2835_dma_free(od); + + return 0; +} + +static struct platform_driver bcm2835_dma_driver = { + .probe = bcm2835_dma_probe, + .remove = bcm2835_dma_remove, + .driver = { + .name = "bcm2835-dma", + .of_match_table = of_match_ptr(bcm2835_dma_of_match), + }, +}; + +module_platform_driver(bcm2835_dma_driver); + +MODULE_ALIAS("platform:bcm2835-dma"); +MODULE_DESCRIPTION("BCM2835 DMA engine driver"); +MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>"); +MODULE_LICENSE("GPL"); |