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Message-ID: <20080316213002.GA2589@lixom.net>
Date: Sun, 16 Mar 2008 16:30:02 -0500
From: Olof Johansson <olof@...om.net>
To: dan.j.williams@...el.com, shannon.nelson@...el.com
Cc: linux-kernel@...r.kernel.org, pasemi-linux@...abs.org,
linuxppc-dev@...abs.org, hskinnemoen@...el.com
Subject: [PATCH v2] pasemi_dma: Driver for PA Semi PWRficient on-chip DMA
engine
pasemi_dma: Driver for PA Semi PWRficient on-chip DMA engine
DMA copy offload driver for PA Semi PWRficient. It uses the
platform-specific functions to allocate channels, etc.
Signed-off-by: Olof Johansson <olof@...om.net>
---
Changes since last post:
* Add DMA_INTERRUPT support and handling of the interrupt flag
* Fix interrupt handler for above and add tasklet
* Switch to spin_lock_bh() where possible
* Remove empty dependency_added() function since it's no longer
used in the framework.
* Fix bug in "ring full" estimation.
Note that this still needs to go on top of the powerpc.git tree due to the
pasemi_dma.h updates that this driver depends on. I suggest merging this
through pasemi.git->powerpc.git->linus with an Acked-by from the DMA guys.
-Olof
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index a703def..e4fd7e5 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -37,6 +37,13 @@ config INTEL_IOP_ADMA
help
Enable support for the Intel(R) IOP Series RAID engines.
+config PASEMI_DMA
+ tristate "PA Semi DMA Engine support"
+ depends on PPC_PASEMI
+ select DMA_ENGINE
+ help
+ Enable support for the DMA Engine on PA Semi PWRficient SoCs
+
config DMA_ENGINE
bool
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index b152cd8..72bf45c 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_NET_DMA) += iovlock.o
obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
ioatdma-objs := ioat.o ioat_dma.o ioat_dca.o
obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
+obj-$(CONFIG_PASEMI_DMA) += pasemi_dma.o
diff --git a/drivers/dma/pasemi_dma.c b/drivers/dma/pasemi_dma.c
new file mode 100644
index 0000000..ad6235b
--- /dev/null
+++ b/drivers/dma/pasemi_dma.c
@@ -0,0 +1,532 @@
+/*
+ * Driver for the PA Semi PWRficient DMA Engine (copy parts)
+ * Copyright (c) 2007,2008 Olof Johansson, PA Semi, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/pasemi_dma.h>
+
+#define MAX_CH 16
+#define MAX_XFER 0x40000
+#define RING_SZ 8192
+
+struct pasemi_dma_desc {
+ u64 src;
+ u64 dest;
+ dma_addr_t src_dma;
+ dma_addr_t dest_dma;
+ size_t len;
+ struct list_head node;
+ enum dma_prep_flags flags;
+ struct dma_async_tx_descriptor async_tx;
+ struct pasemi_dma_chan *chan;
+};
+
+struct pasemi_dma_chan {
+ struct pasemi_dmachan chan;
+ spinlock_t ring_lock; /* Protects the ring only */
+ spinlock_t desc_lock; /* Protects the descriptor list */
+ struct pasemi_dma *dma_dev;
+ struct pasemi_dma_desc *ring_info[RING_SZ]; /* softc */
+ unsigned int next_to_fill;
+ unsigned int next_to_clean;
+ struct dma_chan common;
+ struct list_head free_desc;
+ int desc_count;
+ int in_use;
+ struct tasklet_struct tasklet;
+};
+
+struct pasemi_dma {
+ struct pci_dev *pdev;
+ struct dma_device common;
+ struct pasemi_dma_chan *chans[MAX_CH];
+};
+
+static unsigned int channels = 4;
+module_param(channels, uint, S_IRUGO);
+MODULE_PARM_DESC(channels, "Number of channels for copy (default: 2)");
+
+#define to_pasemi_dma_chan(chan) container_of(chan, struct pasemi_dma_chan, \
+ common)
+#define to_pasemi_dma_desc(lh) container_of(lh, struct pasemi_dma_desc, node)
+#define tx_to_desc_sw(tx) container_of(tx, struct pasemi_dma_desc, async_tx)
+
+static void pasemi_dma_clean(struct pasemi_dma_chan *chan)
+{
+ int old, new, i;
+ struct pasemi_dma_desc *desc;
+ dma_async_tx_callback callback;
+
+restart:
+ spin_lock_bh(&chan->desc_lock);
+
+ old = chan->next_to_clean;
+
+ new = *chan->chan.status & PAS_STATUS_PCNT_M;
+ new <<= 2;
+ new &= (RING_SZ-1);
+
+ if (old > new)
+ new += RING_SZ;
+
+ for (i = old; i < new; i += 4) {
+ if (unlikely(chan->chan.ring_virt[i & (RING_SZ-1)] & XCT_COPY_O))
+ break;
+ desc = chan->ring_info[i & (RING_SZ-1)];
+
+ callback = desc->async_tx.callback;
+ if (callback) {
+ /* Can't re-lock and just loop, since another cpu
+ * might have came in here while we released the lock.
+ * Instead, start all over again to re-read status words.
+ */
+ chan->next_to_clean = i & (RING_SZ-1);
+ spin_unlock_bh(&chan->desc_lock);
+ callback(desc->async_tx.callback_param);
+ goto restart;
+ }
+
+ list_add_tail(&desc->node, &chan->free_desc);
+ }
+
+ chan->next_to_clean = i & (RING_SZ-1);
+
+ spin_unlock_bh(&chan->desc_lock);
+}
+
+static void pasemi_dma_tasklet(unsigned long data)
+{
+ struct pasemi_dma_chan *chan = (struct pasemi_dma_chan *)data;
+
+ pasemi_dma_clean(chan);
+}
+
+static int pasemi_dma_intr(int irq, void *data)
+{
+ struct pasemi_dma_chan *dma_chan = data;
+ const struct pasemi_dmachan *chan = &dma_chan->chan;
+ u64 status;
+ unsigned int reg;
+
+ status = *chan->status;
+
+ if (!(status & PAS_STATUS_CAUSE_M))
+ return IRQ_NONE;
+
+ reg = PAS_IOB_DMA_TXCH_RESET_PINTC |
+ S_IOB_DMA_RXCH_RESET_PCNT(status & PAS_STATUS_PCNT_M);
+
+ if (status & PAS_STATUS_SOFT)
+ reg |= PAS_IOB_DMA_TXCH_RESET_SINTC;
+ if (status & PAS_STATUS_ERROR)
+ reg |= PAS_IOB_DMA_TXCH_RESET_DINTC;
+
+ tasklet_schedule(&dma_chan->tasklet);
+
+ if (reg)
+ pasemi_write_iob_reg(PAS_IOB_DMA_TXCH_RESET(chan->chno), reg);
+
+ return IRQ_HANDLED;
+}
+
+static int pasemi_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct pasemi_dma_chan *ch = to_pasemi_dma_chan(chan);
+ u32 val;
+ unsigned int cfg;
+ int ret, chno;
+
+ if (ch->in_use)
+ return RING_SZ;
+
+ spin_lock_init(&ch->ring_lock);
+ spin_lock_init(&ch->desc_lock);
+
+ chno = ch->chan.chno;
+
+ ret = pasemi_dma_alloc_ring(&ch->chan, RING_SZ);
+ if (ret) {
+ printk(KERN_INFO "pasemi_dma: Failed to allocate descriptor ring: %d\n", ret);
+ return ret;
+ }
+
+ ch->in_use = 1;
+
+ /* Set CNTTH to something large since we don't want to use count-based
+ * interrupts, but we still need to take them.
+ */
+ pasemi_write_iob_reg(PAS_IOB_DMA_TXCH_CFG(chno),
+ PAS_IOB_DMA_TXCH_CFG_CNTTH(0xfff));
+
+ pasemi_write_iob_reg(PAS_IOB_DMA_TXCH_RESET(chno), 0x30);
+
+ pasemi_write_dma_reg(PAS_DMA_TXCHAN_BASEL(chno),
+ PAS_DMA_TXCHAN_BASEL_BRBL(ch->chan.ring_dma));
+
+ val = PAS_DMA_TXCHAN_BASEU_BRBH(ch->chan.ring_dma >> 32);
+ val |= PAS_DMA_TXCHAN_BASEU_SIZ(ch->chan.ring_size >> 3);
+
+ pasemi_write_dma_reg(PAS_DMA_TXCHAN_BASEU(chno), val);
+
+ cfg = PAS_DMA_TXCHAN_CFG_TY_COPY |
+ PAS_DMA_TXCHAN_CFG_UP |
+ PAS_DMA_TXCHAN_CFG_LPDQ |
+ PAS_DMA_TXCHAN_CFG_LPSQ |
+ PAS_DMA_TXCHAN_CFG_WT(4);
+
+ pasemi_write_dma_reg(PAS_DMA_TXCHAN_CFG(chno), cfg);
+
+ pasemi_dma_start_chan(&ch->chan, PAS_DMA_TXCHAN_TCMDSTA_SZ |
+ PAS_DMA_TXCHAN_TCMDSTA_DB |
+ PAS_DMA_TXCHAN_TCMDSTA_DE |
+ PAS_DMA_TXCHAN_TCMDSTA_DA);
+
+ ch->next_to_fill = 0;
+ ch->next_to_clean = 0;
+ ch->desc_count = 0;
+
+ return ch->chan.ring_size/4;
+}
+
+static void pasemi_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct pasemi_dma_chan *ch = to_pasemi_dma_chan(chan);
+
+ if (ch->in_use)
+ pasemi_dma_free_ring(&ch->chan);
+
+ ch->in_use = 0;
+
+ return;
+}
+
+static enum dma_status pasemi_dma_is_complete(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ dma_cookie_t *done,
+ dma_cookie_t *used)
+{
+ struct pasemi_dma_chan *ch = to_pasemi_dma_chan(chan);
+ dma_cookie_t clean, fill;
+ int tries = 1;
+ enum dma_status ret;
+
+ pasemi_dma_clean(ch);
+
+ do {
+ clean = (ch->next_to_clean - 4) & (RING_SZ-1);
+ fill = (ch->next_to_fill - 1) & (RING_SZ-1) ;
+
+ if (done)
+ *done = clean;
+ if (used)
+ *used = fill;
+
+ ret = dma_async_is_complete(cookie, clean, fill);
+ } while (ret != DMA_SUCCESS && --tries);
+
+ return ret;
+}
+
+
+static void pasemi_dma_issue_pending(struct dma_chan *chan)
+{
+ return;
+}
+
+
+static dma_cookie_t
+pasemi_tx_submit_memcpy(struct dma_async_tx_descriptor *tx)
+{
+ struct pasemi_dma_desc *desc = tx_to_desc_sw(tx);
+ struct pasemi_dma_chan *chan = desc->chan;
+ u64 xct[4], *ring;
+ int idx, len;
+
+ len = desc->len;
+ if (unlikely(!len)) {
+ xct[0] = XCT_COPY_DTY_PREF;
+ len = 1;
+ } else
+ xct[0] = 0;
+
+ /* Check if interrupt was requested */
+ if (desc->flags & DMA_PREP_INTERRUPT)
+ xct[0] |= XCT_COPY_I;
+
+ xct[0] |= XCT_COPY_O | XCT_COPY_LLEN(len);
+ xct[1] = XCT_PTR_LEN(len) | XCT_PTR_ADDR(desc->dest) | XCT_PTR_T;
+ xct[2] = XCT_PTR_LEN(len) | XCT_PTR_ADDR(desc->src);
+ xct[3] = 0;
+
+ spin_lock_bh(&chan->ring_lock);
+
+ idx = chan->next_to_fill;
+
+ ring = chan->chan.ring_virt;
+
+ /* This is where we copy stuff to the ring */
+
+ ring[idx & (RING_SZ-1)] = xct[0];
+ ring[(idx+1) & (RING_SZ-1)] = xct[1];
+ ring[(idx+2) & (RING_SZ-1)] = xct[2];
+ ring[(idx+3) & (RING_SZ-1)] = xct[3];
+
+ chan->next_to_fill = (chan->next_to_fill + 4) & (RING_SZ-1);
+
+ chan->ring_info[idx] = desc;
+
+ pasemi_write_dma_reg(PAS_DMA_TXCHAN_INCR(chan->chan.chno), 2);
+
+ spin_unlock_bh(&chan->ring_lock);
+ return idx;
+}
+
+static struct pasemi_dma_desc *
+pasemi_dma_alloc_descriptor(struct pasemi_dma_chan *ch, gfp_t flags)
+{
+ struct pasemi_dma_desc *desc;
+ int retries;
+
+retry:
+ spin_lock_bh(&ch->desc_lock);
+
+ if (!list_empty(&ch->free_desc)) {
+ desc = list_entry(ch->free_desc.next, struct pasemi_dma_desc,
+ node);
+ list_del(&desc->node);
+ spin_unlock_bh(&ch->desc_lock);
+ return desc;
+ }
+
+ if (ch->desc_count >= (RING_SZ/4)) {
+ spin_unlock_bh(&ch->desc_lock);
+ if (!retries++) {
+ pasemi_dma_clean(ch);
+ goto retry;
+ }
+ return NULL;
+ }
+ ch->desc_count++;
+ spin_unlock_bh(&ch->desc_lock);
+
+ /* try to get another desc */
+ desc = kzalloc(sizeof(*desc), flags);
+ if (unlikely(!desc))
+ return NULL;
+
+ dma_async_tx_descriptor_init(&desc->async_tx, &ch->common);
+ desc->chan = ch;
+ INIT_LIST_HEAD(&desc->async_tx.tx_list);
+
+ /* will this ever happen? */
+ BUG_ON(!desc);
+
+ return desc;
+}
+
+static struct dma_async_tx_descriptor *
+pasemi_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dma_dest,
+ dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+ struct pasemi_dma_chan *ch = to_pasemi_dma_chan(chan);
+ struct pasemi_dma_desc *desc;
+
+ if (len >= MAX_XFER) {
+ if (printk_ratelimit())
+ printk(KERN_WARNING "pasemi_dma: Copy request too long (%ld > %d)\n",
+ len, MAX_XFER);
+ return NULL;
+ }
+
+ desc = pasemi_dma_alloc_descriptor(ch, GFP_KERNEL);
+ if (!desc)
+ return NULL;
+
+ desc->async_tx.tx_submit = pasemi_tx_submit_memcpy;
+ desc->len = len;
+ desc->dest = dma_dest;
+ desc->src = dma_src;
+ desc->flags = flags;
+
+ return &desc->async_tx;
+}
+
+/* The DMA API assumes there's a way to create an "interrupt only" descriptor.
+ * Our DMA engine doesn't have that concept, so let's create a dummy 1-byte
+ * prefetch descriptor just like 0-size memcpy, but with the _SE and _I bit set.
+ */
+static struct dma_async_tx_descriptor *
+pasemi_dma_prep_interrupt(struct dma_chan *chan)
+{
+ dma_addr_t dummy = to_pasemi_dma_chan(chan)->chan.ring_dma;
+
+ return pasemi_dma_prep_memcpy(chan, dummy, dummy, 0, DMA_PREP_INTERRUPT);
+}
+
+static int enumerate_dma_channels(struct pasemi_dma *device)
+{
+ int i, ret;
+ struct pasemi_dma_chan *ch;
+
+ device->common.chancnt = channels;
+
+ for (i = 0; i < device->common.chancnt; i++) {
+ ch = pasemi_dma_alloc_chan(TXCHAN, sizeof(*ch),
+ offsetof(struct pasemi_dma_chan,
+ chan));
+ ch->dma_dev = device;
+ ch->common.device = &device->common;
+ tasklet_init(&ch->tasklet, pasemi_dma_tasklet, (unsigned long)ch);
+ ret = request_irq(ch->chan.irq, &pasemi_dma_intr, IRQF_DISABLED,
+ "pasemi_dma", ch);
+ if (ret) {
+ printk(KERN_INFO "pasemi_dma: request of irq %d failed: %d\n",
+ ch->chan.irq, ret);
+ return ret;
+ }
+ INIT_LIST_HEAD(&ch->free_desc);
+ list_add_tail(&ch->common.device_node,
+ &device->common.channels);
+ }
+ return device->common.chancnt;
+}
+
+static int __devinit pasemi_dma_probe(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ int err;
+ struct pasemi_dma *device;
+ struct dma_device *dma_dev;
+
+ err = pci_enable_device(pdev);
+ if (err)
+ goto err_enable_device;
+
+ device = kzalloc(sizeof(*device), GFP_KERNEL);
+ if (!device) {
+ err = -ENOMEM;
+ goto err_kzalloc;
+ }
+
+ device->pdev = pdev;
+ pci_set_drvdata(pdev, device);
+
+ dma_dev = &device->common;
+
+ INIT_LIST_HEAD(&dma_dev->channels);
+ enumerate_dma_channels(device);
+
+ dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
+ dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);
+ dma_dev->device_alloc_chan_resources = pasemi_dma_alloc_chan_resources;
+ dma_dev->device_free_chan_resources = pasemi_dma_free_chan_resources;
+ dma_dev->device_prep_dma_memcpy = pasemi_dma_prep_memcpy;
+ dma_dev->device_prep_dma_interrupt = pasemi_dma_prep_interrupt;
+ dma_dev->device_is_tx_complete = pasemi_dma_is_complete;
+ dma_dev->device_issue_pending = pasemi_dma_issue_pending;
+ dma_dev->dev = &pdev->dev;
+
+ printk(KERN_INFO "PA Semi DMA Engine found, using %d channels for copy\n",
+ dma_dev->chancnt);
+
+ err = dma_async_device_register(dma_dev);
+
+ return err;
+
+err_kzalloc:
+ pci_disable_device(pdev);
+err_enable_device:
+
+ printk(KERN_ERR "PA Semi DMA Engine initialization failed\n");
+
+ return err;
+}
+
+static void pasemi_dma_shutdown(struct pci_dev *pdev)
+{
+ struct pasemi_dma *device;
+ device = pci_get_drvdata(pdev);
+
+ dma_async_device_unregister(&device->common);
+}
+
+static void __devexit pasemi_dma_remove(struct pci_dev *pdev)
+{
+ struct pasemi_dma *device;
+ struct dma_chan *chan, *_chan;
+ struct pasemi_dma_chan *pasemi_ch;
+
+ device = pci_get_drvdata(pdev);
+ dma_async_device_unregister(&device->common);
+
+ list_for_each_entry_safe(chan, _chan, &device->common.channels,
+ device_node) {
+ pasemi_ch = to_pasemi_dma_chan(chan);
+ free_irq(pasemi_ch->chan.irq, pasemi_ch);
+ list_del(&chan->device_node);
+ pasemi_dma_free_chan(&pasemi_ch->chan);
+ }
+
+ pci_disable_device(pdev);
+ kfree(device);
+}
+
+static struct pci_device_id pasemi_dma_pci_tbl[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_PASEMI, 0xa007) },
+ { }
+};
+MODULE_DEVICE_TABLE(pci, pasemi_dma_pci_tbl);
+
+static struct pci_driver pasemi_dma_pci_driver = {
+ .name = "pasemi_dma",
+ .id_table = pasemi_dma_pci_tbl,
+ .probe = pasemi_dma_probe,
+ .shutdown = pasemi_dma_shutdown,
+ .remove = __devexit_p(pasemi_dma_remove),
+};
+
+
+static int __init pasemi_dma_init_module(void)
+{
+ int err;
+
+ err = pasemi_dma_init();
+ if (err)
+ return err;
+
+ return pci_register_driver(&pasemi_dma_pci_driver);
+}
+
+module_init(pasemi_dma_init_module);
+
+static void __exit pasemi_dma_exit_module(void)
+{
+ pci_unregister_driver(&pasemi_dma_pci_driver);
+}
+
+module_exit(pasemi_dma_exit_module);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Olof Johansson <olof@...om.net>");
+MODULE_DESCRIPTION("PA Semi PWRficient DMA Engine driver");
--
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