From 5fa4eb7d17acff35c1ea9a7def5dec5802566565 Mon Sep 17 00:00:00 2001
From: Florian Meier <florian.meier@koalo.de>
Date: Fri, 22 Nov 2013 14:22:53 +0100
Subject: [PATCH 114/174] dmaengine: Add support for BCM2708
Add support for DMA controller of BCM2708 as used in the Raspberry Pi.
Currently it only supports cyclic DMA.
Signed-off-by: Florian Meier <florian.meier@koalo.de>
---
drivers/dma/Kconfig | 6 +
drivers/dma/Makefile | 1 +
drivers/dma/bcm2708-dmaengine.c | 588 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 595 insertions(+)
create mode 100644 drivers/dma/bcm2708-dmaengine.c
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -305,6 +305,12 @@ config DMA_OMAP
select DMA_ENGINE
select DMA_VIRTUAL_CHANNELS
+config DMA_BCM2708
+ tristate "BCM2708 DMA engine support"
+ depends on MACH_BCM2708
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+
config MMP_PDMA
bool "MMP PDMA support"
depends on (ARCH_MMP || ARCH_PXA)
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -37,4 +37,5 @@ obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
obj-$(CONFIG_DMA_OMAP) += omap-dma.o
+obj-$(CONFIG_DMA_BCM2708) += bcm2708-dmaengine.o
obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
--- /dev/null
+++ b/drivers/dma/bcm2708-dmaengine.c
@@ -0,0 +1,588 @@
+/*
+ * BCM2708 DMA engine support
+ *
+ * This driver only supports cyclic DMA transfers
+ * as needed for the I2S module.
+ *
+ * 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.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.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/irq.h>
+
+#include "virt-dma.h"
+
+#include <mach/dma.h>
+#include <mach/irqs.h>
+
+struct bcm2708_dmadev {
+ struct dma_device ddev;
+ spinlock_t lock;
+ void __iomem *base;
+ struct device_dma_parameters dma_parms;
+};
+
+struct bcm2708_chan {
+ struct virt_dma_chan vc;
+ struct list_head node;
+
+ struct dma_slave_config cfg;
+ bool cyclic;
+
+ int ch;
+ struct bcm2708_desc *desc;
+
+ void __iomem *chan_base;
+ int irq_number;
+};
+
+struct bcm2708_desc {
+ struct virt_dma_desc vd;
+ enum dma_transfer_direction dir;
+
+ unsigned int control_block_size;
+ struct bcm2708_dma_cb *control_block_base;
+ dma_addr_t control_block_base_phys;
+
+ unsigned frames;
+ size_t size;
+};
+
+#define BCM2708_DMA_DATA_TYPE_S8 1
+#define BCM2708_DMA_DATA_TYPE_S16 2
+#define BCM2708_DMA_DATA_TYPE_S32 4
+#define BCM2708_DMA_DATA_TYPE_S128 16
+
+static inline struct bcm2708_dmadev *to_bcm2708_dma_dev(struct dma_device *d)
+{
+ return container_of(d, struct bcm2708_dmadev, ddev);
+}
+
+static inline struct bcm2708_chan *to_bcm2708_dma_chan(struct dma_chan *c)
+{
+ return container_of(c, struct bcm2708_chan, vc.chan);
+}
+
+static inline struct bcm2708_desc *to_bcm2708_dma_desc(
+ struct dma_async_tx_descriptor *t)
+{
+ return container_of(t, struct bcm2708_desc, vd.tx);
+}
+
+static void bcm2708_dma_desc_free(struct virt_dma_desc *vd)
+{
+ struct bcm2708_desc *desc = container_of(vd, struct bcm2708_desc, vd);
+ dma_free_coherent(desc->vd.tx.chan->device->dev,
+ desc->control_block_size,
+ desc->control_block_base,
+ desc->control_block_base_phys);
+ kfree(desc);
+}
+
+static void bcm2708_dma_start_desc(struct bcm2708_chan *c)
+{
+ struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
+ struct bcm2708_desc *d;
+
+ if (!vd) {
+ c->desc = NULL;
+ return;
+ }
+
+ list_del(&vd->node);
+
+ c->desc = d = to_bcm2708_dma_desc(&vd->tx);
+
+ bcm_dma_start(c->chan_base, d->control_block_base_phys);
+}
+
+static irqreturn_t bcm2708_dma_callback(int irq, void *data)
+{
+ struct bcm2708_chan *c = data;
+ struct bcm2708_desc *d;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+
+ /* Acknowledge interrupt */
+ writel(BCM2708_DMA_INT, c->chan_base + BCM2708_DMA_CS);
+
+ d = c->desc;
+
+ if (d) {
+ /* TODO Only works for cyclic DMA */
+ vchan_cyclic_callback(&d->vd);
+ }
+
+ /* Keep the DMA engine running */
+ dsb(); /* ARM synchronization barrier */
+ writel(BCM2708_DMA_ACTIVE, c->chan_base + BCM2708_DMA_CS);
+
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static int bcm2708_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct bcm2708_chan *c = to_bcm2708_dma_chan(chan);
+
+ return request_irq(c->irq_number,
+ bcm2708_dma_callback, 0, "DMA IRQ", c);
+}
+
+static void bcm2708_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct bcm2708_chan *c = to_bcm2708_dma_chan(chan);
+
+ vchan_free_chan_resources(&c->vc);
+ free_irq(c->irq_number, c);
+
+ dev_dbg(c->vc.chan.device->dev, "Freeing DMA channel %u\n", c->ch);
+}
+
+static size_t bcm2708_dma_desc_size(struct bcm2708_desc *d)
+{
+ return d->size;
+}
+
+static size_t bcm2708_dma_desc_size_pos(struct bcm2708_desc *d, dma_addr_t addr)
+{
+ unsigned i;
+ size_t size;
+
+ for (size = i = 0; i < d->frames; i++) {
+ struct bcm2708_dma_cb *control_block =
+ &d->control_block_base[i];
+ 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 bcm2708_dma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+ struct bcm2708_chan *c = to_bcm2708_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_SUCCESS || !txstate)
+ return ret;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ vd = vchan_find_desc(&c->vc, cookie);
+ if (vd) {
+ txstate->residue =
+ bcm2708_dma_desc_size(to_bcm2708_dma_desc(&vd->tx));
+ } else if (c->desc && c->desc->vd.tx.cookie == cookie) {
+ struct bcm2708_desc *d = c->desc;
+ dma_addr_t pos;
+
+ if (d->dir == DMA_MEM_TO_DEV)
+ pos = readl(c->chan_base + BCM2708_DMA_SOURCE_AD);
+ else if (d->dir == DMA_DEV_TO_MEM)
+ pos = readl(c->chan_base + BCM2708_DMA_DEST_AD);
+ else
+ pos = 0;
+
+ txstate->residue = bcm2708_dma_desc_size_pos(d, pos);
+ } else {
+ txstate->residue = 0;
+ }
+
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return ret;
+}
+
+static void bcm2708_dma_issue_pending(struct dma_chan *chan)
+{
+ struct bcm2708_chan *c = to_bcm2708_dma_chan(chan);
+ unsigned long flags;
+
+ c->cyclic = true; /* Nothing else is implemented */
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (vchan_issue_pending(&c->vc) && !c->desc)
+ bcm2708_dma_start_desc(c);
+
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *bcm2708_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, void *context)
+{
+ struct bcm2708_chan *c = to_bcm2708_dma_chan(chan);
+ enum dma_slave_buswidth dev_width;
+ struct bcm2708_desc *d;
+ dma_addr_t dev_addr;
+ unsigned es, sync_type;
+ unsigned frame;
+
+ /* Grab configuration */
+ if (direction == DMA_DEV_TO_MEM) {
+ dev_addr = c->cfg.src_addr;
+ dev_width = c->cfg.src_addr_width;
+ sync_type = BCM2708_DMA_S_DREQ;
+ } else if (direction == DMA_MEM_TO_DEV) {
+ dev_addr = c->cfg.dst_addr;
+ dev_width = c->cfg.dst_addr_width;
+ sync_type = BCM2708_DMA_D_DREQ;
+ } else {
+ dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
+ return NULL;
+ }
+
+ /* Bus width translates to the element size (ES) */
+ switch (dev_width) {
+ case DMA_SLAVE_BUSWIDTH_4_BYTES:
+ es = BCM2708_DMA_DATA_TYPE_S32;
+ break;
+ default:
+ return NULL;
+ }
+
+ /* Now allocate and setup the descriptor. */
+ d = kzalloc(sizeof(*d), GFP_NOWAIT);
+ if (!d)
+ return NULL;
+
+ d->dir = direction;
+ d->frames = buf_len / period_len;
+
+ /* Allocate memory for control blocks */
+ d->control_block_size = d->frames * sizeof(struct bcm2708_dma_cb);
+ d->control_block_base = dma_zalloc_coherent(chan->device->dev,
+ d->control_block_size, &d->control_block_base_phys,
+ GFP_NOWAIT);
+
+ if (!d->control_block_base) {
+ kfree(d);
+ return NULL;
+ }
+
+ /*
+ * Iterate over all frames, create a control block
+ * for each frame and link them together.
+ */
+ for (frame = 0; frame < d->frames; frame++) {
+ struct bcm2708_dma_cb *control_block =
+ &d->control_block_base[frame];
+
+ /* Setup adresses */
+ if (d->dir == DMA_DEV_TO_MEM) {
+ control_block->info = BCM2708_DMA_D_INC;
+ control_block->src = dev_addr;
+ control_block->dst = buf_addr + frame * period_len;
+ } else {
+ control_block->info = BCM2708_DMA_S_INC;
+ control_block->src = buf_addr + frame * period_len;
+ control_block->dst = dev_addr;
+ }
+
+ /* Enable interrupt */
+ control_block->info |= BCM2708_DMA_INT_EN;
+
+ /* Setup synchronization */
+ if (sync_type != 0)
+ control_block->info |= sync_type;
+
+ /* Setup DREQ channel */
+ if (c->cfg.slave_id != 0)
+ control_block->info |=
+ BCM2708_DMA_PER_MAP(c->cfg.slave_id);
+
+ /* Length of a frame */
+ control_block->length = period_len;
+ d->size += control_block->length;
+
+ /*
+ * Next block is the next frame.
+ * This DMA engine driver currently only supports cyclic DMA.
+ * Therefore, wrap around at number of frames.
+ */
+ control_block->next = d->control_block_base_phys +
+ sizeof(struct bcm2708_dma_cb)
+ * ((frame + 1) % d->frames);
+ }
+
+ return vchan_tx_prep(&c->vc, &d->vd, flags);
+}
+
+static int bcm2708_dma_slave_config(struct bcm2708_chan *c,
+ struct dma_slave_config *cfg)
+{
+ if ((cfg->direction == DMA_DEV_TO_MEM &&
+ cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) ||
+ (cfg->direction == DMA_MEM_TO_DEV &&
+ cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) ||
+ !is_slave_direction(cfg->direction)) {
+ return -EINVAL;
+ }
+
+ c->cfg = *cfg;
+
+ return 0;
+}
+
+static int bcm2708_dma_terminate_all(struct bcm2708_chan *c)
+{
+ struct bcm2708_dmadev *d = to_bcm2708_dma_dev(c->vc.chan.device);
+ unsigned long flags;
+ int timeout = 10000;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+
+ /* Prevent this channel being scheduled */
+ spin_lock(&d->lock);
+ list_del_init(&c->node);
+ spin_unlock(&d->lock);
+
+ /*
+ * Stop DMA activity: we assume the callback will not be called
+ * after bcm_dma_abort() returns (even if it does, it will see
+ * c->desc is NULL and exit.)
+ */
+ if (c->desc) {
+ c->desc = NULL;
+ bcm_dma_abort(c->chan_base);
+
+ /* Wait for stopping */
+ while (timeout > 0) {
+ timeout--;
+ if (!(readl(c->chan_base + BCM2708_DMA_CS) &
+ BCM2708_DMA_ACTIVE))
+ break;
+
+ cpu_relax();
+ }
+
+ if (timeout <= 0)
+ dev_err(d->ddev.dev, "DMA transfer could not be terminated\n");
+ }
+
+ 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 int bcm2708_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+ unsigned long arg)
+{
+ struct bcm2708_chan *c = to_bcm2708_dma_chan(chan);
+
+ switch (cmd) {
+ case DMA_SLAVE_CONFIG:
+ return bcm2708_dma_slave_config(c,
+ (struct dma_slave_config *)arg);
+
+ case DMA_TERMINATE_ALL:
+ return bcm2708_dma_terminate_all(c);
+
+ default:
+ return -ENXIO;
+ }
+}
+
+static int bcm2708_dma_chan_init(struct bcm2708_dmadev *d, void __iomem* chan_base,
+ int chan_id, int irq)
+{
+ struct bcm2708_chan *c;
+
+ c = devm_kzalloc(d->ddev.dev, sizeof(*c), GFP_KERNEL);
+ if (!c)
+ return -ENOMEM;
+
+ c->vc.desc_free = bcm2708_dma_desc_free;
+ vchan_init(&c->vc, &d->ddev);
+ INIT_LIST_HEAD(&c->node);
+
+ d->ddev.chancnt++;
+
+ c->chan_base = chan_base;
+ c->ch = chan_id;
+ c->irq_number = irq;
+
+ return 0;
+}
+
+static void bcm2708_dma_free(struct bcm2708_dmadev *od)
+{
+ while (!list_empty(&od->ddev.channels)) {
+ struct bcm2708_chan *c = list_first_entry(&od->ddev.channels,
+ struct bcm2708_chan, vc.chan.device_node);
+
+ list_del(&c->vc.chan.device_node);
+ tasklet_kill(&c->vc.task);
+ }
+}
+
+static int bcm2708_dma_probe(struct platform_device *pdev)
+{
+ struct bcm2708_dmadev *od;
+ int rc, i;
+
+ if (!pdev->dev.dma_mask)
+ pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
+
+ rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
+ if (rc)
+ return rc;
+ dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
+
+ od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
+ if (!od)
+ return -ENOMEM;
+
+ pdev->dev.dma_parms = &od->dma_parms;
+ dma_set_max_seg_size(&pdev->dev, 0x3FFFFFFF);
+
+ dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+ dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
+ od->ddev.device_alloc_chan_resources = bcm2708_dma_alloc_chan_resources;
+ od->ddev.device_free_chan_resources = bcm2708_dma_free_chan_resources;
+ od->ddev.device_tx_status = bcm2708_dma_tx_status;
+ od->ddev.device_issue_pending = bcm2708_dma_issue_pending;
+ od->ddev.device_prep_dma_cyclic = bcm2708_dma_prep_dma_cyclic;
+ od->ddev.device_control = bcm2708_dma_control;
+ od->ddev.dev = &pdev->dev;
+ INIT_LIST_HEAD(&od->ddev.channels);
+ spin_lock_init(&od->lock);
+
+ platform_set_drvdata(pdev, od);
+
+ for (i = 0; i < 16; i++) {
+ void __iomem* chan_base;
+ int chan_id, irq;
+
+ chan_id = bcm_dma_chan_alloc(BCM_DMA_FEATURE_FAST,
+ &chan_base,
+ &irq);
+
+ if (chan_id < 0)
+ break;
+
+ rc = bcm2708_dma_chan_init(od, chan_base, chan_id, irq);
+ if (rc) {
+ bcm2708_dma_free(od);
+ return rc;
+ }
+ }
+
+ rc = dma_async_device_register(&od->ddev);
+ if (rc) {
+ dev_err(&pdev->dev,
+ "Failed to register slave DMA engine device: %d\n", rc);
+ bcm2708_dma_free(od);
+ return rc;
+ }
+
+ dev_dbg(&pdev->dev, "Load BCM2708 DMA engine driver\n");
+
+ return rc;
+}
+
+static int bcm2708_dma_remove(struct platform_device *pdev)
+{
+ struct bcm2708_dmadev *od = platform_get_drvdata(pdev);
+
+ dma_async_device_unregister(&od->ddev);
+ bcm2708_dma_free(od);
+
+ return 0;
+}
+
+static struct platform_driver bcm2708_dma_driver = {
+ .probe = bcm2708_dma_probe,
+ .remove = bcm2708_dma_remove,
+ .driver = {
+ .name = "bcm2708-dmaengine",
+ .owner = THIS_MODULE,
+ },
+};
+
+static struct platform_device *pdev;
+
+static const struct platform_device_info bcm2708_dma_dev_info = {
+ .name = "bcm2708-dmaengine",
+ .id = -1,
+};
+
+static int bcm2708_dma_init(void)
+{
+ int rc = platform_driver_register(&bcm2708_dma_driver);
+
+ if (rc == 0) {
+ pdev = platform_device_register_full(&bcm2708_dma_dev_info);
+ if (IS_ERR(pdev)) {
+ platform_driver_unregister(&bcm2708_dma_driver);
+ rc = PTR_ERR(pdev);
+ }
+ }
+
+ return rc;
+}
+subsys_initcall(bcm2708_dma_init);
+
+static void __exit bcm2708_dma_exit(void)
+{
+ platform_device_unregister(pdev);
+ platform_driver_unregister(&bcm2708_dma_driver);
+}
+module_exit(bcm2708_dma_exit);
+
+MODULE_ALIAS("platform:bcm2708-dma");
+MODULE_DESCRIPTION("BCM2708 DMA engine driver");
+MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>");
+MODULE_LICENSE("GPL v2");