From 615c164da0eb42cbfb1688cb429cc4d5039db5d8 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 5 Jul 2019 17:14:21 +0300 Subject: 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 Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20190705141425.19894-2-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/intel_th/msu.c | 388 +++++++++++++++++++++++++++++++++++++-- drivers/hwtracing/intel_th/msu.h | 20 +- 2 files changed, 379 insertions(+), 29 deletions(-) (limited to 'drivers/hwtracing') 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 #include #include +#include #include #ifdef CONFIG_X86 #include #endif +#include #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; -- cgit