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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-07-05 17:14:21 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-25 14:03:18 +0300
commit615c164da0eb42cbfb1688cb429cc4d5039db5d8 (patch)
tree5b2de647c457cf257c8afef1dfa50af0af8ea833 /drivers/hwtracing
parentdb4ad308a50620c8a24419dcc6556fabaf594c0e (diff)
downloadlinux-615c164da0eb42cbfb1688cb429cc4d5039db5d8.tar.xz
intel_th: msu: Introduce buffer interface
Introduces a concept of external buffers, which is a mechanism for creating trace sinks that would receive trace data from MSC buffers and transfer it elsewhere. A external buffer can implement its own window allocation/deallocation if it has to. It must provide a callback that's used to notify it when a window fills up, so that it can then start a DMA transaction from that window 'elsewhere'. This window remains in a 'locked' state and won't be used for storing new trace data until the buffer 'unlocks' it with a provided API call, at which point the window can be used again for storing trace data. This relies on a functional "last block" interrupt, so not all versions of Trace Hub can use this feature, which does not reflect on existing users. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190705141425.19894-2-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/intel_th/msu.c388
-rw-r--r--drivers/hwtracing/intel_th/msu.h20
2 files changed, 379 insertions, 29 deletions
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index 8ab28e5fb366..08413e6a075f 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -17,21 +17,48 @@
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/io.h>
+#include <linux/workqueue.h>
#include <linux/dma-mapping.h>
#ifdef CONFIG_X86
#include <asm/set_memory.h>
#endif
+#include <linux/intel_th.h>
#include "intel_th.h"
#include "msu.h"
#define msc_dev(x) (&(x)->thdev->dev)
+/*
+ * Lockout state transitions:
+ * READY -> INUSE -+-> LOCKED -+-> READY -> etc.
+ * \-----------/
+ * WIN_READY: window can be used by HW
+ * WIN_INUSE: window is in use
+ * WIN_LOCKED: window is filled up and is being processed by the buffer
+ * handling code
+ *
+ * All state transitions happen automatically, except for the LOCKED->READY,
+ * which needs to be signalled by the buffer code by calling
+ * intel_th_msc_window_unlock().
+ *
+ * When the interrupt handler has to switch to the next window, it checks
+ * whether it's READY, and if it is, it performs the switch and tracing
+ * continues. If it's LOCKED, it stops the trace.
+ */
+enum lockout_state {
+ WIN_READY = 0,
+ WIN_INUSE,
+ WIN_LOCKED
+};
+
/**
* struct msc_window - multiblock mode window descriptor
* @entry: window list linkage (msc::win_list)
* @pgoff: page offset into the buffer that this window starts at
+ * @lockout: lockout state, see comment below
+ * @lo_lock: lockout state serialization
* @nr_blocks: number of blocks (pages) in this window
* @nr_segs: number of segments in this window (<= @nr_blocks)
* @_sgt: array of block descriptors
@@ -40,6 +67,8 @@
struct msc_window {
struct list_head entry;
unsigned long pgoff;
+ enum lockout_state lockout;
+ spinlock_t lo_lock;
unsigned int nr_blocks;
unsigned int nr_segs;
struct msc *msc;
@@ -77,6 +106,8 @@ struct msc_iter {
* struct msc - MSC device representation
* @reg_base: register window base address
* @thdev: intel_th_device pointer
+ * @mbuf: MSU buffer, if assigned
+ * @mbuf_priv MSU buffer's private data, if @mbuf
* @win_list: list of windows in multiblock mode
* @single_sgt: single mode buffer
* @cur_win: current window
@@ -100,6 +131,10 @@ struct msc {
void __iomem *msu_base;
struct intel_th_device *thdev;
+ const struct msu_buffer *mbuf;
+ void *mbuf_priv;
+
+ struct work_struct work;
struct list_head win_list;
struct sg_table single_sgt;
struct msc_window *cur_win;
@@ -126,6 +161,101 @@ struct msc {
unsigned int index;
};
+static LIST_HEAD(msu_buffer_list);
+static struct mutex msu_buffer_mutex;
+
+/**
+ * struct msu_buffer_entry - internal MSU buffer bookkeeping
+ * @entry: link to msu_buffer_list
+ * @mbuf: MSU buffer object
+ * @owner: module that provides this MSU buffer
+ */
+struct msu_buffer_entry {
+ struct list_head entry;
+ const struct msu_buffer *mbuf;
+ struct module *owner;
+};
+
+static struct msu_buffer_entry *__msu_buffer_entry_find(const char *name)
+{
+ struct msu_buffer_entry *mbe;
+
+ lockdep_assert_held(&msu_buffer_mutex);
+
+ list_for_each_entry(mbe, &msu_buffer_list, entry) {
+ if (!strcmp(mbe->mbuf->name, name))
+ return mbe;
+ }
+
+ return NULL;
+}
+
+static const struct msu_buffer *
+msu_buffer_get(const char *name)
+{
+ struct msu_buffer_entry *mbe;
+
+ mutex_lock(&msu_buffer_mutex);
+ mbe = __msu_buffer_entry_find(name);
+ if (mbe && !try_module_get(mbe->owner))
+ mbe = NULL;
+ mutex_unlock(&msu_buffer_mutex);
+
+ return mbe ? mbe->mbuf : NULL;
+}
+
+static void msu_buffer_put(const struct msu_buffer *mbuf)
+{
+ struct msu_buffer_entry *mbe;
+
+ mutex_lock(&msu_buffer_mutex);
+ mbe = __msu_buffer_entry_find(mbuf->name);
+ if (mbe)
+ module_put(mbe->owner);
+ mutex_unlock(&msu_buffer_mutex);
+}
+
+int intel_th_msu_buffer_register(const struct msu_buffer *mbuf,
+ struct module *owner)
+{
+ struct msu_buffer_entry *mbe;
+ int ret = 0;
+
+ mbe = kzalloc(sizeof(*mbe), GFP_KERNEL);
+ if (!mbe)
+ return -ENOMEM;
+
+ mutex_lock(&msu_buffer_mutex);
+ if (__msu_buffer_entry_find(mbuf->name)) {
+ ret = -EEXIST;
+ kfree(mbe);
+ goto unlock;
+ }
+
+ mbe->mbuf = mbuf;
+ mbe->owner = owner;
+ list_add_tail(&mbe->entry, &msu_buffer_list);
+unlock:
+ mutex_unlock(&msu_buffer_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(intel_th_msu_buffer_register);
+
+void intel_th_msu_buffer_unregister(const struct msu_buffer *mbuf)
+{
+ struct msu_buffer_entry *mbe;
+
+ mutex_lock(&msu_buffer_mutex);
+ mbe = __msu_buffer_entry_find(mbuf->name);
+ if (mbe) {
+ list_del(&mbe->entry);
+ kfree(mbe);
+ }
+ mutex_unlock(&msu_buffer_mutex);
+}
+EXPORT_SYMBOL_GPL(intel_th_msu_buffer_unregister);
+
static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
{
/* header hasn't been written */
@@ -188,6 +318,25 @@ static struct msc_window *msc_next_window(struct msc_window *win)
return list_next_entry(win, entry);
}
+static size_t msc_win_total_sz(struct msc_window *win)
+{
+ unsigned int blk;
+ size_t size = 0;
+
+ for (blk = 0; blk < win->nr_segs; blk++) {
+ struct msc_block_desc *bdesc = msc_win_block(win, blk);
+
+ if (msc_block_wrapped(bdesc))
+ return win->nr_blocks << PAGE_SHIFT;
+
+ size += msc_total_sz(bdesc);
+ if (msc_block_last_written(bdesc))
+ break;
+ }
+
+ return size;
+}
+
/**
* msc_find_window() - find a window matching a given sg_table
* @msc: MSC device
@@ -527,6 +676,9 @@ static int intel_th_msu_init(struct msc *msc)
if (!msc->do_irq)
return 0;
+ if (!msc->mbuf)
+ return 0;
+
mintctl = ioread32(msc->msu_base + REG_MSU_MINTCTL);
mintctl |= msc->index ? M1BLIE : M0BLIE;
iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
@@ -554,6 +706,44 @@ static void intel_th_msu_deinit(struct msc *msc)
iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
}
+static int msc_win_set_lockout(struct msc_window *win,
+ enum lockout_state expect,
+ enum lockout_state new)
+{
+ enum lockout_state old;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!win->msc->mbuf)
+ return 0;
+
+ spin_lock_irqsave(&win->lo_lock, flags);
+ old = win->lockout;
+
+ if (old != expect) {
+ ret = -EINVAL;
+ dev_warn_ratelimited(msc_dev(win->msc),
+ "expected lockout state %d, got %d\n",
+ expect, old);
+ goto unlock;
+ }
+
+ win->lockout = new;
+
+unlock:
+ spin_unlock_irqrestore(&win->lo_lock, flags);
+
+ if (ret) {
+ if (expect == WIN_READY && old == WIN_LOCKED)
+ return -EBUSY;
+
+ /* from intel_th_msc_window_unlock(), don't warn if not locked */
+ if (expect == WIN_LOCKED && old == new)
+ return 0;
+ }
+
+ return ret;
+}
/**
* msc_configure() - set up MSC hardware
* @msc: the MSC device to configure
@@ -571,8 +761,12 @@ static int msc_configure(struct msc *msc)
if (msc->mode > MSC_MODE_MULTI)
return -ENOTSUPP;
- if (msc->mode == MSC_MODE_MULTI)
+ if (msc->mode == MSC_MODE_MULTI) {
+ if (msc_win_set_lockout(msc->cur_win, WIN_READY, WIN_INUSE))
+ return -EBUSY;
+
msc_buffer_clear_hw_header(msc);
+ }
reg = msc->base_addr >> PAGE_SHIFT;
iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
@@ -594,10 +788,14 @@ static int msc_configure(struct msc *msc)
iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+ intel_th_msu_init(msc);
+
msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
intel_th_trace_enable(msc->thdev);
msc->enabled = 1;
+ if (msc->mbuf && msc->mbuf->activate)
+ msc->mbuf->activate(msc->mbuf_priv);
return 0;
}
@@ -611,10 +809,17 @@ static int msc_configure(struct msc *msc)
*/
static void msc_disable(struct msc *msc)
{
+ struct msc_window *win = msc->cur_win;
u32 reg;
lockdep_assert_held(&msc->buf_mutex);
+ if (msc->mode == MSC_MODE_MULTI)
+ msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
+
+ if (msc->mbuf && msc->mbuf->deactivate)
+ msc->mbuf->deactivate(msc->mbuf_priv);
+ intel_th_msu_deinit(msc);
intel_th_trace_disable(msc->thdev);
if (msc->mode == MSC_MODE_SINGLE) {
@@ -630,6 +835,11 @@ static void msc_disable(struct msc *msc)
reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
reg &= ~MSC_EN;
iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+
+ if (msc->mbuf && msc->mbuf->ready)
+ msc->mbuf->ready(msc->mbuf_priv, win->sgt,
+ msc_win_total_sz(win));
+
msc->enabled = 0;
iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
@@ -640,6 +850,10 @@ static void msc_disable(struct msc *msc)
reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
+
+ reg = ioread32(msc->reg_base + REG_MSU_MSUSTS);
+ reg &= msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
+ iowrite32(reg, msc->reg_base + REG_MSU_MSUSTS);
}
static int intel_th_msc_activate(struct intel_th_device *thdev)
@@ -856,6 +1070,8 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
win->msc = msc;
win->sgt = &win->_sgt;
+ win->lockout = WIN_READY;
+ spin_lock_init(&win->lo_lock);
if (!list_empty(&msc->win_list)) {
struct msc_window *prev = list_last_entry(&msc->win_list,
@@ -865,8 +1081,13 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
win->pgoff = prev->pgoff + prev->nr_blocks;
}
- ret = __msc_buffer_win_alloc(win, nr_blocks);
- if (ret < 0)
+ if (msc->mbuf && msc->mbuf->alloc_window)
+ ret = msc->mbuf->alloc_window(msc->mbuf_priv, &win->sgt,
+ nr_blocks << PAGE_SHIFT);
+ else
+ ret = __msc_buffer_win_alloc(win, nr_blocks);
+
+ if (ret <= 0)
goto err_nomem;
msc_buffer_set_uc(win, ret);
@@ -925,7 +1146,10 @@ static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
msc_buffer_set_wb(win);
- __msc_buffer_win_free(msc, win);
+ if (msc->mbuf && msc->mbuf->free_window)
+ msc->mbuf->free_window(msc->mbuf_priv, win->sgt);
+ else
+ __msc_buffer_win_free(msc, win);
kfree(win);
}
@@ -1462,18 +1686,77 @@ static void msc_win_switch(struct msc *msc)
intel_th_trace_switch(msc->thdev);
}
+/**
+ * intel_th_msc_window_unlock - put the window back in rotation
+ * @dev: MSC device to which this relates
+ * @sgt: buffer's sg_table for the window, does nothing if NULL
+ */
+void intel_th_msc_window_unlock(struct device *dev, struct sg_table *sgt)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+ struct msc_window *win;
+
+ if (!sgt)
+ return;
+
+ win = msc_find_window(msc, sgt, false);
+ if (!win)
+ return;
+
+ msc_win_set_lockout(win, WIN_LOCKED, WIN_READY);
+}
+EXPORT_SYMBOL_GPL(intel_th_msc_window_unlock);
+
+static void msc_work(struct work_struct *work)
+{
+ struct msc *msc = container_of(work, struct msc, work);
+
+ intel_th_msc_deactivate(msc->thdev);
+}
+
static irqreturn_t intel_th_msc_interrupt(struct intel_th_device *thdev)
{
struct msc *msc = dev_get_drvdata(&thdev->dev);
u32 msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
u32 mask = msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
+ struct msc_window *win, *next_win;
- if (!(msusts & mask)) {
- if (msc->enabled)
- return IRQ_HANDLED;
+ if (!msc->do_irq || !msc->mbuf)
return IRQ_NONE;
+
+ msusts &= mask;
+
+ if (!msusts)
+ return msc->enabled ? IRQ_HANDLED : IRQ_NONE;
+
+ iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
+
+ if (!msc->enabled)
+ return IRQ_NONE;
+
+ /* grab the window before we do the switch */
+ win = msc->cur_win;
+ if (!win)
+ return IRQ_HANDLED;
+ next_win = msc_next_window(win);
+ if (!next_win)
+ return IRQ_HANDLED;
+
+ /* next window: if READY, proceed, if LOCKED, stop the trace */
+ if (msc_win_set_lockout(next_win, WIN_READY, WIN_INUSE)) {
+ schedule_work(&msc->work);
+ return IRQ_HANDLED;
}
+ /* current window: INUSE -> LOCKED */
+ msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
+
+ msc_win_switch(msc);
+
+ if (msc->mbuf && msc->mbuf->ready)
+ msc->mbuf->ready(msc->mbuf_priv, win->sgt,
+ msc_win_total_sz(win));
+
return IRQ_HANDLED;
}
@@ -1511,21 +1794,43 @@ wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
static DEVICE_ATTR_RW(wrap);
+static void msc_buffer_unassign(struct msc *msc)
+{
+ lockdep_assert_held(&msc->buf_mutex);
+
+ if (!msc->mbuf)
+ return;
+
+ msc->mbuf->unassign(msc->mbuf_priv);
+ msu_buffer_put(msc->mbuf);
+ msc->mbuf_priv = NULL;
+ msc->mbuf = NULL;
+}
+
static ssize_t
mode_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct msc *msc = dev_get_drvdata(dev);
+ const char *mode = msc_mode[msc->mode];
+ ssize_t ret;
+
+ mutex_lock(&msc->buf_mutex);
+ if (msc->mbuf)
+ mode = msc->mbuf->name;
+ ret = scnprintf(buf, PAGE_SIZE, "%s\n", mode);
+ mutex_unlock(&msc->buf_mutex);
- return scnprintf(buf, PAGE_SIZE, "%s\n", msc_mode[msc->mode]);
+ return ret;
}
static ssize_t
mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
size_t size)
{
+ const struct msu_buffer *mbuf = NULL;
struct msc *msc = dev_get_drvdata(dev);
size_t len = size;
- char *cp;
+ char *cp, *mode;
int i, ret;
if (!capable(CAP_SYS_RAWIO))
@@ -1535,17 +1840,59 @@ mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
if (cp)
len = cp - buf;
- for (i = 0; i < ARRAY_SIZE(msc_mode); i++)
- if (!strncmp(msc_mode[i], buf, len))
- goto found;
+ mode = kstrndup(buf, len, GFP_KERNEL);
+ i = match_string(msc_mode, ARRAY_SIZE(msc_mode), mode);
+ if (i >= 0)
+ goto found;
+
+ /* Buffer sinks only work with a usable IRQ */
+ if (!msc->do_irq) {
+ kfree(mode);
+ return -EINVAL;
+ }
+
+ mbuf = msu_buffer_get(mode);
+ kfree(mode);
+ if (mbuf)
+ goto found;
return -EINVAL;
found:
mutex_lock(&msc->buf_mutex);
+ ret = 0;
+
+ /* Same buffer: do nothing */
+ if (mbuf && mbuf == msc->mbuf) {
+ /* put the extra reference we just got */
+ msu_buffer_put(mbuf);
+ goto unlock;
+ }
+
ret = msc_buffer_unlocked_free_unless_used(msc);
- if (!ret)
- msc->mode = i;
+ if (ret)
+ goto unlock;
+
+ if (mbuf) {
+ void *mbuf_priv = mbuf->assign(dev, &i);
+
+ if (!mbuf_priv) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ msc_buffer_unassign(msc);
+ msc->mbuf_priv = mbuf_priv;
+ msc->mbuf = mbuf;
+ } else {
+ msc_buffer_unassign(msc);
+ }
+
+ msc->mode = i;
+
+unlock:
+ if (ret && mbuf)
+ msu_buffer_put(mbuf);
mutex_unlock(&msc->buf_mutex);
return ret ? ret : size;
@@ -1667,7 +2014,12 @@ win_switch_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
mutex_lock(&msc->buf_mutex);
- if (msc->mode != MSC_MODE_MULTI)
+ /*
+ * Window switch can only happen in the "multi" mode.
+ * If a external buffer is engaged, they have the full
+ * control over window switching.
+ */
+ if (msc->mode != MSC_MODE_MULTI || msc->mbuf)
ret = -ENOTSUPP;
else
msc_win_switch(msc);
@@ -1720,10 +2072,7 @@ static int intel_th_msc_probe(struct intel_th_device *thdev)
msc->reg_base = base + msc->index * 0x100;
msc->msu_base = base;
- err = intel_th_msu_init(msc);
- if (err)
- return err;
-
+ INIT_WORK(&msc->work, msc_work);
err = intel_th_msc_init(msc);
if (err)
return err;
@@ -1739,7 +2088,6 @@ static void intel_th_msc_remove(struct intel_th_device *thdev)
int ret;
intel_th_msc_deactivate(thdev);
- intel_th_msu_deinit(msc);
/*
* Buffers should not be used at this point except if the
diff --git a/drivers/hwtracing/intel_th/msu.h b/drivers/hwtracing/intel_th/msu.h
index 574c16004cb2..3f527dd4d727 100644
--- a/drivers/hwtracing/intel_th/msu.h
+++ b/drivers/hwtracing/intel_th/msu.h
@@ -44,14 +44,6 @@ enum {
#define M0BLIE BIT(16)
#define M1BLIE BIT(24)
-/* MSC operating modes (MSC_MODE) */
-enum {
- MSC_MODE_SINGLE = 0,
- MSC_MODE_MULTI,
- MSC_MODE_EXI,
- MSC_MODE_DEBUG,
-};
-
/* MSCnSTS bits */
#define MSCSTS_WRAPSTAT BIT(1) /* Wrap occurred */
#define MSCSTS_PLE BIT(2) /* Pipeline Empty */
@@ -93,6 +85,16 @@ static inline unsigned long msc_data_sz(struct msc_block_desc *bdesc)
return bdesc->valid_dw * 4 - MSC_BDESC;
}
+static inline unsigned long msc_total_sz(struct msc_block_desc *bdesc)
+{
+ return bdesc->valid_dw * 4;
+}
+
+static inline unsigned long msc_block_sz(struct msc_block_desc *bdesc)
+{
+ return bdesc->block_sz * 64 - MSC_BDESC;
+}
+
static inline bool msc_block_wrapped(struct msc_block_desc *bdesc)
{
if (bdesc->hw_tag & (MSC_HW_TAG_BLOCKWRAP | MSC_HW_TAG_WINWRAP))
@@ -104,7 +106,7 @@ static inline bool msc_block_wrapped(struct msc_block_desc *bdesc)
static inline bool msc_block_last_written(struct msc_block_desc *bdesc)
{
if ((bdesc->hw_tag & MSC_HW_TAG_ENDBIT) ||
- (msc_data_sz(bdesc) != DATA_IN_PAGE))
+ (msc_data_sz(bdesc) != msc_block_sz(bdesc)))
return true;
return false;