[PATCH char-misc-next 5/8] misc: mic: add dma support in host driver

From: Sudeep Dutt
Date: Tue May 27 2014 - 22:38:37 EST

From: Siva Yerramreddy <yshivakrishna@xxxxxxxxx>

This patch adds a dma device on the mic virtual bus and uses this dmaengine
to transfer data for virtio devices

Reviewed-by: Nikhil Rao <nikhil.rao@xxxxxxxxx>
Signed-off-by: Sudeep Dutt <sudeep.dutt@xxxxxxxxx>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
Signed-off-by: Siva Yerramreddy <yshivakrishna@xxxxxxxxx>
---
drivers/misc/mic/Kconfig | 2 +-
drivers/misc/mic/host/mic_boot.c | 78 +++++++++++++++-
drivers/misc/mic/host/mic_device.h | 24 +++++
drivers/misc/mic/host/mic_intr.h | 3 +-
drivers/misc/mic/host/mic_virtio.c | 179 +++++++++++++++++++++++++++++--------
drivers/misc/mic/host/mic_virtio.h | 21 ++++-
drivers/misc/mic/host/mic_x100.c | 8 ++
7 files changed, 274 insertions(+), 41 deletions(-)

diff --git a/drivers/misc/mic/Kconfig b/drivers/misc/mic/Kconfig
index ee1d2ac..bf76313 100644
--- a/drivers/misc/mic/Kconfig
+++ b/drivers/misc/mic/Kconfig
@@ -19,7 +19,7 @@ comment "Intel MIC Host Driver"

config INTEL_MIC_HOST
tristate "Intel MIC Host Driver"
- depends on 64BIT && PCI && X86
+ depends on 64BIT && PCI && X86 && INTEL_MIC_BUS
select VHOST_RING
help
This enables Host Driver support for the Intel Many Integrated
diff --git a/drivers/misc/mic/host/mic_boot.c b/drivers/misc/mic/host/mic_boot.c
index b75c6b5..b462177 100644
--- a/drivers/misc/mic/host/mic_boot.c
+++ b/drivers/misc/mic/host/mic_boot.c
@@ -23,11 +23,66 @@
#include <linux/pci.h>

#include <linux/mic_common.h>
+#include <linux/mic_bus.h>
#include "../common/mic_dev.h"
#include "mic_device.h"
#include "mic_smpt.h"
#include "mic_virtio.h"

+static inline struct mic_device *mbdev_to_mdev(struct mbus_device *mbdev)
+{
+ return dev_get_drvdata(mbdev->dev.parent);
+}
+
+static dma_addr_t mic_dma_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ void *va = phys_to_virt(page_to_phys(page)) + offset;
+ struct mic_device *mdev = mbdev_to_mdev(dev_get_drvdata(dev));
+
+ return mic_map_single(mdev, va, size);
+}
+
+static void mic_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
+ size_t size, enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ struct mic_device *mdev = mbdev_to_mdev(dev_get_drvdata(dev));
+ mic_unmap_single(mdev, dma_addr, size);
+}
+
+static struct dma_map_ops mic_dma_ops = {
+ .map_page = mic_dma_map_page,
+ .unmap_page = mic_dma_unmap_page,
+};
+
+static struct mic_irq *_mic_request_threaded_irq(struct mbus_device *mbdev,
+ irq_handler_t handler, irq_handler_t thread_fn,
+ const char *name, void *data, int intr_src)
+{
+ return mic_request_threaded_irq(mbdev_to_mdev(mbdev), handler,
+ thread_fn, name, data,
+ intr_src, MIC_INTR_DMA);
+}
+
+static void _mic_free_irq(struct mbus_device *mbdev,
+ struct mic_irq *cookie, void *data)
+{
+ return mic_free_irq(mbdev_to_mdev(mbdev), cookie, data);
+}
+
+static void _mic_ack_interrupt(struct mbus_device *mbdev, int num)
+{
+ struct mic_device *mdev = mbdev_to_mdev(mbdev);
+ mdev->ops->intr_workarounds(mdev);
+}
+
+static struct mbus_hw_ops mbus_hw_ops = {
+ .request_threaded_irq = _mic_request_threaded_irq,
+ .free_irq = _mic_free_irq,
+ .ack_interrupt = _mic_ack_interrupt,
+};
+
/**
* mic_reset - Reset the MIC device.
* @mdev: pointer to mic_device instance
@@ -95,9 +150,20 @@ retry:
*/
goto retry;
}
- rc = mdev->ops->load_mic_fw(mdev, buf);
+ rc = mbus_add_device(&mdev->dma_mbdev, mdev->sdev->parent,
+ MBUS_DEV_DMA_HOST, &mic_dma_ops, &mbus_hw_ops,
+ mdev->mmio.va);
if (rc)
goto unlock_ret;
+
+ mdev->dma_ch = mic_request_dma_chan(mdev);
+ if (!mdev->dma_ch) {
+ rc = -ENXIO;
+ goto dma_remove;
+ }
+ rc = mdev->ops->load_mic_fw(mdev, buf);
+ if (rc)
+ goto dma_release;
mic_smpt_restore(mdev);
mic_intr_restore(mdev);
mdev->intr_ops->enable_interrupts(mdev);
@@ -105,6 +171,11 @@ retry:
mdev->ops->write_spad(mdev, MIC_DPHI_SPAD, mdev->dp_dma_addr >> 32);
mdev->ops->send_firmware_intr(mdev);
mic_set_state(mdev, MIC_ONLINE);
+ goto unlock_ret;
+dma_release:
+ dma_release_channel(mdev->dma_ch);
+dma_remove:
+ mbus_remove_device(&mdev->dma_mbdev);
unlock_ret:
mutex_unlock(&mdev->mic_mutex);
return rc;
@@ -122,6 +193,11 @@ void mic_stop(struct mic_device *mdev, bool force)
mutex_lock(&mdev->mic_mutex);
if (MIC_OFFLINE != mdev->state || force) {
mic_virtio_reset_devices(mdev);
+ if (mdev->dma_ch) {
+ dma_release_channel(mdev->dma_ch);
+ mdev->dma_ch = NULL;
+ }
+ mbus_remove_device(&mdev->dma_mbdev);
mic_bootparam_init(mdev);
mic_reset(mdev);
if (MIC_RESET_FAILED == mdev->state)
diff --git a/drivers/misc/mic/host/mic_device.h b/drivers/misc/mic/host/mic_device.h
index 0398c69..7583a80 100644
--- a/drivers/misc/mic/host/mic_device.h
+++ b/drivers/misc/mic/host/mic_device.h
@@ -25,6 +25,8 @@
#include <linux/idr.h>
#include <linux/notifier.h>
#include <linux/irqreturn.h>
+#include <linux/dmaengine.h>
+#include <linux/mic_bus.h>

#include "mic_intr.h"

@@ -87,6 +89,8 @@ enum mic_stepping {
* @cdev: Character device for MIC.
* @vdev_list: list of virtio devices.
* @pm_notifier: Handles PM notifications from the OS.
+ * @dma_mbdev: MIC BUS DMA device.
+ * @dma_ch: DMA channel reserved by this driver for use by virtio devices.
*/
struct mic_device {
struct mic_mw mmio;
@@ -124,6 +128,8 @@ struct mic_device {
struct cdev cdev;
struct list_head vdev_list;
struct notifier_block pm_notifier;
+ struct mbus_device dma_mbdev;
+ struct dma_chan *dma_ch;
};

/**
@@ -144,6 +150,7 @@ struct mic_device {
* @load_mic_fw: Load firmware segments required to boot the card
* into card memory. This includes the kernel, command line, ramdisk etc.
* @get_postcode: Get post code status from firmware.
+ * @dma_filter: DMA filter function to be used.
*/
struct mic_hw_ops {
u8 aper_bar;
@@ -159,6 +166,7 @@ struct mic_hw_ops {
void (*send_firmware_intr)(struct mic_device *mdev);
int (*load_mic_fw)(struct mic_device *mdev, const char *buf);
u32 (*get_postcode)(struct mic_device *mdev);
+ bool (*dma_filter)(struct dma_chan *chan, void *param);
};

/**
@@ -187,6 +195,22 @@ mic_mmio_write(struct mic_mw *mw, u32 val, u32 offset)
iowrite32(val, mw->va + offset);
}

+static inline struct dma_chan *mic_request_dma_chan(struct mic_device *mdev)
+{
+ dma_cap_mask_t mask;
+ struct dma_chan *chan;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_MEMCPY, mask);
+ chan = dma_request_channel(mask, mdev->ops->dma_filter,
+ mdev->sdev->parent);
+ if (chan)
+ return chan;
+ dev_err(mdev->sdev->parent, "%s %d unable to acquire channel\n",
+ __func__, __LINE__);
+ return NULL;
+}
+
void mic_sysfs_init(struct mic_device *mdev);
int mic_start(struct mic_device *mdev, const char *buf);
void mic_stop(struct mic_device *mdev, bool force);
diff --git a/drivers/misc/mic/host/mic_intr.h b/drivers/misc/mic/host/mic_intr.h
index 6b03f84..dd354ff 100644
--- a/drivers/misc/mic/host/mic_intr.h
+++ b/drivers/misc/mic/host/mic_intr.h
@@ -27,8 +27,9 @@
* The minimum number of msix vectors required for normal operation.
* 3 for virtio network, console and block devices.
* 1 for card shutdown notifications.
+ * 4 for host owned DMA channels.
*/
-#define MIC_MIN_MSIX 4
+#define MIC_MIN_MSIX 8
#define MIC_NUM_OFFSETS 32

/**
diff --git a/drivers/misc/mic/host/mic_virtio.c b/drivers/misc/mic/host/mic_virtio.c
index aba3e83..aa8e4d6 100644
--- a/drivers/misc/mic/host/mic_virtio.c
+++ b/drivers/misc/mic/host/mic_virtio.c
@@ -21,60 +21,155 @@
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
-
+#include <linux/dmaengine.h>
#include <linux/mic_common.h>
+
#include "../common/mic_dev.h"
#include "mic_device.h"
#include "mic_smpt.h"
#include "mic_virtio.h"

/*
- * Initiates the copies across the PCIe bus from card memory to
- * a user space buffer.
+ * Size of the internal buffer used during DMA's as an intermediate buffer
+ * for copy to/from user.
*/
-static int mic_virtio_copy_to_user(struct mic_vdev *mvdev,
- void __user *ubuf, size_t len, u64 addr)
+#define MIC_INT_DMA_BUF_SIZE PAGE_ALIGN(64 * 1024ULL)
+
+static int mic_sync_dma(struct mic_device *mdev, dma_addr_t dst,
+ dma_addr_t src, size_t len)
{
- int err;
- void __iomem *dbuf = mvdev->mdev->aper.va + addr;
- /*
- * We are copying from IO below an should ideally use something
- * like copy_to_user_fromio(..) if it existed.
- */
- if (copy_to_user(ubuf, (void __force *)dbuf, len)) {
- err = -EFAULT;
- dev_err(mic_dev(mvdev), "%s %d err %d\n",
+ int err = 0;
+ struct dma_async_tx_descriptor *tx;
+ struct dma_chan *mic_ch = mdev->dma_ch;
+
+ if (!mic_ch) {
+ err = -EBUSY;
+ goto error;
+ }
+
+ tx = mic_ch->device->device_prep_dma_memcpy(mic_ch, dst, src, len,
+ DMA_PREP_FENCE);
+ if (!tx) {
+ err = -ENOMEM;
+ goto error;
+ } else {
+ dma_cookie_t cookie = tx->tx_submit(tx);
+
+ err = dma_submit_error(cookie);
+ if (err)
+ goto error;
+ err = dma_sync_wait(mic_ch, cookie);
+ }
+error:
+ if (err)
+ dev_err(mdev->sdev->parent, "%s %d err %d\n",
__func__, __LINE__, err);
- goto err;
+ return err;
+}
+
+/*
+ * Initiates the copies across the PCIe bus from card memory to a user
+ * space buffer. When transfers are done using DMA, source/destination
+ * addresses and transfer length must follow the alignment requirements of
+ * the MIC DMA engine.
+ */
+static int mic_virtio_copy_to_user(struct mic_vdev *mvdev, void __user *ubuf,
+ size_t len, u64 daddr, size_t dlen, int vr_idx)
+{
+ struct mic_device *mdev = mvdev->mdev;
+ void __iomem *dbuf = mdev->aper.va + daddr;
+ struct mic_vringh *mvr = &mvdev->mvr[vr_idx];
+ size_t dma_alignment = 1 << mdev->dma_ch->device->copy_align;
+ size_t dma_offset;
+ size_t partlen;
+ int err;
+
+ dma_offset = daddr - round_down(daddr, dma_alignment);
+ daddr -= dma_offset;
+ len += dma_offset;
+
+ while (len) {
+ partlen = min_t(size_t, len, MIC_INT_DMA_BUF_SIZE);
+
+ err = mic_sync_dma(mdev, mvr->buf_da, daddr,
+ ALIGN(partlen, dma_alignment));
+ if (err)
+ goto err;
+
+ if (copy_to_user(ubuf, mvr->buf + dma_offset,
+ partlen - dma_offset)) {
+ err = -EFAULT;
+ goto err;
+ }
+ daddr += partlen;
+ ubuf += partlen;
+ dbuf += partlen;
+ mvdev->in_bytes_dma += partlen;
+ mvdev->in_bytes += partlen;
+ len -= partlen;
+ dma_offset = 0;
}
- mvdev->in_bytes += len;
- err = 0;
+ return 0;
err:
+ dev_err(mic_dev(mvdev), "%s %d err %d\n", __func__, __LINE__, err);
return err;
}

/*
- * Initiates copies across the PCIe bus from a user space
- * buffer to card memory.
+ * Initiates copies across the PCIe bus from a user space buffer to card
+ * memory. When transfers are done using DMA, source/destination addresses
+ * and transfer length must follow the alignment requirements of the MIC
+ * DMA engine.
*/
-static int mic_virtio_copy_from_user(struct mic_vdev *mvdev,
- void __user *ubuf, size_t len, u64 addr)
+static int mic_virtio_copy_from_user(struct mic_vdev *mvdev, void __user *ubuf,
+ size_t len, u64 daddr, size_t dlen, int vr_idx)
{
+ struct mic_device *mdev = mvdev->mdev;
+ void __iomem *dbuf = mdev->aper.va + daddr;
+ struct mic_vringh *mvr = &mvdev->mvr[vr_idx];
+ size_t dma_alignment = 1 << mdev->dma_ch->device->copy_align;
+ size_t partlen;
int err;
- void __iomem *dbuf = mvdev->mdev->aper.va + addr;
+
+ if (daddr & (dma_alignment - 1)) {
+ mvdev->tx_dst_unaligned += len;
+ goto memcpy;
+ } else if (ALIGN(len, dma_alignment) > dlen) {
+ mvdev->tx_len_unaligned += len;
+ goto memcpy;
+ }
+
+ while (len) {
+ partlen = min_t(size_t, len, MIC_INT_DMA_BUF_SIZE);
+
+ if (copy_from_user(mvr->buf, ubuf, partlen)) {
+ err = -EFAULT;
+ goto err;
+ }
+ err = mic_sync_dma(mdev, daddr, mvr->buf_da,
+ ALIGN(partlen, dma_alignment));
+ if (err)
+ goto err;
+ daddr += partlen;
+ ubuf += partlen;
+ dbuf += partlen;
+ mvdev->out_bytes_dma += partlen;
+ mvdev->out_bytes += partlen;
+ len -= partlen;
+ }
+memcpy:
/*
* We are copying to IO below and should ideally use something
* like copy_from_user_toio(..) if it existed.
*/
if (copy_from_user((void __force *)dbuf, ubuf, len)) {
err = -EFAULT;
- dev_err(mic_dev(mvdev), "%s %d err %d\n",
- __func__, __LINE__, err);
goto err;
}
mvdev->out_bytes += len;
- err = 0;
+ return 0;
err:
+ dev_err(mic_dev(mvdev), "%s %d err %d\n", __func__, __LINE__, err);
return err;
}

@@ -110,7 +205,8 @@ static inline u32 mic_vringh_iov_consumed(struct vringh_kiov *iov)
* way to override the VRINGH xfer(..) routines as of v3.10.
*/
static int mic_vringh_copy(struct mic_vdev *mvdev, struct vringh_kiov *iov,
- void __user *ubuf, size_t len, bool read, size_t *out_len)
+ void __user *ubuf, size_t len, bool read, int vr_idx,
+ size_t *out_len)
{
int ret = 0;
size_t partlen, tot_len = 0;
@@ -118,13 +214,15 @@ static int mic_vringh_copy(struct mic_vdev *mvdev, struct vringh_kiov *iov,
while (len && iov->i < iov->used) {
partlen = min(iov->iov[iov->i].iov_len, len);
if (read)
- ret = mic_virtio_copy_to_user(mvdev,
- ubuf, partlen,
- (u64)iov->iov[iov->i].iov_base);
+ ret = mic_virtio_copy_to_user(mvdev, ubuf, partlen,
+ (u64)iov->iov[iov->i].iov_base,
+ iov->iov[iov->i].iov_len,
+ vr_idx);
else
- ret = mic_virtio_copy_from_user(mvdev,
- ubuf, partlen,
- (u64)iov->iov[iov->i].iov_base);
+ ret = mic_virtio_copy_from_user(mvdev, ubuf, partlen,
+ (u64)iov->iov[iov->i].iov_base,
+ iov->iov[iov->i].iov_len,
+ vr_idx);
if (ret) {
dev_err(mic_dev(mvdev), "%s %d err %d\n",
__func__, __LINE__, ret);
@@ -192,8 +290,8 @@ static int _mic_virtio_copy(struct mic_vdev *mvdev,
ubuf = iov.iov_base;
}
/* Issue all the read descriptors first */
- ret = mic_vringh_copy(mvdev, riov, ubuf, len,
- MIC_VRINGH_READ, &out_len);
+ ret = mic_vringh_copy(mvdev, riov, ubuf, len, MIC_VRINGH_READ,
+ copy->vr_idx, &out_len);
if (ret) {
dev_err(mic_dev(mvdev), "%s %d err %d\n",
__func__, __LINE__, ret);
@@ -203,8 +301,8 @@ static int _mic_virtio_copy(struct mic_vdev *mvdev,
ubuf += out_len;
copy->out_len += out_len;
/* Issue the write descriptors next */
- ret = mic_vringh_copy(mvdev, wiov, ubuf, len,
- !MIC_VRINGH_READ, &out_len);
+ ret = mic_vringh_copy(mvdev, wiov, ubuf, len, !MIC_VRINGH_READ,
+ copy->vr_idx, &out_len);
if (ret) {
dev_err(mic_dev(mvdev), "%s %d err %d\n",
__func__, __LINE__, ret);
@@ -589,6 +687,10 @@ int mic_virtio_add_device(struct mic_vdev *mvdev,
dev_dbg(mdev->sdev->parent,
"%s %d index %d va %p info %p vr_size 0x%x\n",
__func__, __LINE__, i, vr->va, vr->info, vr_size);
+ mvr->buf = (void *)__get_free_pages(GFP_KERNEL,
+ get_order(MIC_INT_DMA_BUF_SIZE));
+ mvr->buf_da = mic_map_single(mvdev->mdev, mvr->buf,
+ MIC_INT_DMA_BUF_SIZE);
}

snprintf(irqname, sizeof(irqname), "mic%dvirtio%d", mdev->id,
@@ -673,6 +775,11 @@ skip_hot_remove:
vqconfig = mic_vq_config(mvdev->dd);
for (i = 0; i < mvdev->dd->num_vq; i++) {
struct mic_vringh *mvr = &mvdev->mvr[i];
+
+ mic_unmap_single(mvdev->mdev, mvr->buf_da,
+ MIC_INT_DMA_BUF_SIZE);
+ free_pages((unsigned long)mvr->buf,
+ get_order(MIC_INT_DMA_BUF_SIZE));
vringh_kiov_cleanup(&mvr->riov);
vringh_kiov_cleanup(&mvr->wiov);
mic_unmap_single(mdev, le64_to_cpu(vqconfig[i].address),
diff --git a/drivers/misc/mic/host/mic_virtio.h b/drivers/misc/mic/host/mic_virtio.h
index 184f3c8..d574efb 100644
--- a/drivers/misc/mic/host/mic_virtio.h
+++ b/drivers/misc/mic/host/mic_virtio.h
@@ -46,18 +46,23 @@
* @vrh: The host VRINGH used for accessing the card vrings.
* @riov: The VRINGH read kernel IOV.
* @wiov: The VRINGH write kernel IOV.
- * @head: The VRINGH head index address passed to vringh_getdesc_kern(..).
* @vr_mutex: Mutex for synchronizing access to the VRING.
+ * @buf: Temporary kernel buffer used to copy in/out data
+ * from/to the card via DMA.
+ * @buf_da: dma address of buf.
* @mvdev: Back pointer to MIC virtio device for vringh_notify(..).
+ * @head: The VRINGH head index address passed to vringh_getdesc_kern(..).
*/
struct mic_vringh {
struct mic_vring vring;
struct vringh vrh;
struct vringh_kiov riov;
struct vringh_kiov wiov;
- u16 head;
struct mutex vr_mutex;
+ void *buf;
+ dma_addr_t buf_da;
struct mic_vdev *mvdev;
+ u16 head;
};

/**
@@ -69,6 +74,14 @@ struct mic_vringh {
* @poll_wake - Used for waking up threads blocked in poll.
* @out_bytes - Debug stats for number of bytes copied from host to card.
* @in_bytes - Debug stats for number of bytes copied from card to host.
+ * @out_bytes_dma - Debug stats for number of bytes copied from host to card
+ * using DMA.
+ * @in_bytes_dma - Debug stats for number of bytes copied from card to host
+ * using DMA.
+ * @tx_len_unaligned - Debug stats for number of bytes copied to the card where
+ * the transfer length did not have the required DMA alignment.
+ * @tx_dst_unaligned - Debug stats for number of bytes copied where the
+ * destination address on the card did not have the required DMA alignment.
* @mvr - Store per VRING data structures.
* @virtio_bh_work - Work struct used to schedule virtio bottom half handling.
* @dd - Virtio device descriptor.
@@ -84,6 +97,10 @@ struct mic_vdev {
int poll_wake;
unsigned long out_bytes;
unsigned long in_bytes;
+ unsigned long out_bytes_dma;
+ unsigned long in_bytes_dma;
+ unsigned long tx_len_unaligned;
+ unsigned long tx_dst_unaligned;
struct mic_vringh mvr[MIC_MAX_VRINGS];
struct work_struct virtio_bh_work;
struct mic_device_desc *dd;
diff --git a/drivers/misc/mic/host/mic_x100.c b/drivers/misc/mic/host/mic_x100.c
index 5562fdd..b7a21e1 100644
--- a/drivers/misc/mic/host/mic_x100.c
+++ b/drivers/misc/mic/host/mic_x100.c
@@ -549,6 +549,13 @@ struct mic_smpt_ops mic_x100_smpt_ops = {
.set = mic_x100_smpt_set,
};

+static bool mic_x100_dma_filter(struct dma_chan *chan, void *param)
+{
+ if (chan->device->dev->parent == (struct device *)param)
+ return true;
+ return false;
+}
+
struct mic_hw_ops mic_x100_ops = {
.aper_bar = MIC_X100_APER_BAR,
.mmio_bar = MIC_X100_MMIO_BAR,
@@ -563,6 +570,7 @@ struct mic_hw_ops mic_x100_ops = {
.send_firmware_intr = mic_x100_send_firmware_intr,
.load_mic_fw = mic_x100_load_firmware,
.get_postcode = mic_x100_get_postcode,
+ .dma_filter = mic_x100_dma_filter,
};

struct mic_hw_intr_ops mic_x100_intr_ops = {
--
1.8.2.1

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