--- /dev/null
+/*
+ * Intel(R) Trace Hub Memory Storage Unit
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/uaccess.h>
+#include <linux/sizes.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/cacheflush.h>
+
+#include "intel_th.h"
+#include "msu.h"
+
+#define msc_dev(x) (&(x)->thdev->dev)
+
+/**
+ * struct msc_block - multiblock mode block descriptor
+ * @bdesc: pointer to hardware descriptor (beginning of the block)
+ * @addr: physical address of the block
+ */
+struct msc_block {
+ struct msc_block_desc *bdesc;
+ dma_addr_t addr;
+};
+
+/**
+ * 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
+ * @nr_blocks: number of blocks (pages) in this window
+ * @block: array of block descriptors
+ */
+struct msc_window {
+ struct list_head entry;
+ unsigned long pgoff;
+ unsigned int nr_blocks;
+ struct msc *msc;
+ struct msc_block block[0];
+};
+
+/**
+ * struct msc_iter - iterator for msc buffer
+ * @entry: msc::iter_list linkage
+ * @msc: pointer to the MSC device
+ * @start_win: oldest window
+ * @win: current window
+ * @offset: current logical offset into the buffer
+ * @start_block: oldest block in the window
+ * @block: block number in the window
+ * @block_off: offset into current block
+ * @wrap_count: block wrapping handling
+ * @eof: end of buffer reached
+ */
+struct msc_iter {
+ struct list_head entry;
+ struct msc *msc;
+ struct msc_window *start_win;
+ struct msc_window *win;
+ unsigned long offset;
+ int start_block;
+ int block;
+ unsigned int block_off;
+ unsigned int wrap_count;
+ unsigned int eof;
+};
+
+/**
+ * struct msc - MSC device representation
+ * @reg_base: register window base address
+ * @thdev: intel_th_device pointer
+ * @win_list: list of windows in multiblock mode
+ * @nr_pages: total number of pages allocated for this buffer
+ * @single_sz: amount of data in single mode
+ * @single_wrap: single mode wrap occurred
+ * @base: buffer's base pointer
+ * @base_addr: buffer's base address
+ * @user_count: number of users of the buffer
+ * @mmap_count: number of mappings
+ * @buf_mutex: mutex to serialize access to buffer-related bits
+
+ * @enabled: MSC is enabled
+ * @wrap: wrapping is enabled
+ * @mode: MSC operating mode
+ * @burst_len: write burst length
+ * @index: number of this MSC in the MSU
+ */
+struct msc {
+ void __iomem *reg_base;
+ struct intel_th_device *thdev;
+
+ struct list_head win_list;
+ unsigned long nr_pages;
+ unsigned long single_sz;
+ unsigned int single_wrap : 1;
+ void *base;
+ dma_addr_t base_addr;
+
+ /* <0: no buffer, 0: no users, >0: active users */
+ atomic_t user_count;
+
+ atomic_t mmap_count;
+ struct mutex buf_mutex;
+
+ struct mutex iter_mutex;
+ struct list_head iter_list;
+
+ /* config */
+ unsigned int enabled : 1,
+ wrap : 1;
+ unsigned int mode;
+ unsigned int burst_len;
+ unsigned int index;
+};
+
+static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
+{
+ /* header hasn't been written */
+ if (!bdesc->valid_dw)
+ return true;
+
+ /* valid_dw includes the header */
+ if (!msc_data_sz(bdesc))
+ return true;
+
+ return false;
+}
+
+/**
+ * msc_oldest_window() - locate the window with oldest data
+ * @msc: MSC device
+ *
+ * This should only be used in multiblock mode. Caller should hold the
+ * msc::user_count reference.
+ *
+ * Return: the oldest window with valid data
+ */
+static struct msc_window *msc_oldest_window(struct msc *msc)
+{
+ struct msc_window *win;
+ u32 reg = ioread32(msc->reg_base + REG_MSU_MSC0NWSA);
+ unsigned long win_addr = (unsigned long)reg << PAGE_SHIFT;
+ unsigned int found = 0;
+
+ if (list_empty(&msc->win_list))
+ return NULL;
+
+ /*
+ * we might need a radix tree for this, depending on how
+ * many windows a typical user would allocate; ideally it's
+ * something like 2, in which case we're good
+ */
+ list_for_each_entry(win, &msc->win_list, entry) {
+ if (win->block[0].addr == win_addr)
+ found++;
+
+ /* skip the empty ones */
+ if (msc_block_is_empty(win->block[0].bdesc))
+ continue;
+
+ if (found)
+ return win;
+ }
+
+ return list_entry(msc->win_list.next, struct msc_window, entry);
+}
+
+/**
+ * msc_win_oldest_block() - locate the oldest block in a given window
+ * @win: window to look at
+ *
+ * Return: index of the block with the oldest data
+ */
+static unsigned int msc_win_oldest_block(struct msc_window *win)
+{
+ unsigned int blk;
+ struct msc_block_desc *bdesc = win->block[0].bdesc;
+
+ /* without wrapping, first block is the oldest */
+ if (!msc_block_wrapped(bdesc))
+ return 0;
+
+ /*
+ * with wrapping, last written block contains both the newest and the
+ * oldest data for this window.
+ */
+ for (blk = 0; blk < win->nr_blocks; blk++) {
+ bdesc = win->block[blk].bdesc;
+
+ if (msc_block_last_written(bdesc))
+ return blk;
+ }
+
+ return 0;
+}
+
+/**
+ * msc_is_last_win() - check if a window is the last one for a given MSC
+ * @win: window
+ * Return: true if @win is the last window in MSC's multiblock buffer
+ */
+static inline bool msc_is_last_win(struct msc_window *win)
+{
+ return win->entry.next == &win->msc->win_list;
+}
+
+/**
+ * msc_next_window() - return next window in the multiblock buffer
+ * @win: current window
+ *
+ * Return: window following the current one
+ */
+static struct msc_window *msc_next_window(struct msc_window *win)
+{
+ if (msc_is_last_win(win))
+ return list_entry(win->msc->win_list.next, struct msc_window,
+ entry);
+
+ return list_entry(win->entry.next, struct msc_window, entry);
+}
+
+static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
+{
+ return iter->win->block[iter->block].bdesc;
+}
+
+static void msc_iter_init(struct msc_iter *iter)
+{
+ memset(iter, 0, sizeof(*iter));
+ iter->start_block = -1;
+ iter->block = -1;
+}
+
+static struct msc_iter *msc_iter_install(struct msc *msc)
+{
+ struct msc_iter *iter;
+
+ iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return NULL;
+
+ msc_iter_init(iter);
+ iter->msc = msc;
+
+ mutex_lock(&msc->iter_mutex);
+ list_add_tail(&iter->entry, &msc->iter_list);
+ mutex_unlock(&msc->iter_mutex);
+
+ return iter;
+}
+
+static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
+{
+ mutex_lock(&msc->iter_mutex);
+ list_del(&iter->entry);
+ mutex_unlock(&msc->iter_mutex);
+
+ kfree(iter);
+}
+
+static void msc_iter_block_start(struct msc_iter *iter)
+{
+ if (iter->start_block != -1)
+ return;
+
+ iter->start_block = msc_win_oldest_block(iter->win);
+ iter->block = iter->start_block;
+ iter->wrap_count = 0;
+
+ /*
+ * start with the block with oldest data; if data has wrapped
+ * in this window, it should be in this block
+ */
+ if (msc_block_wrapped(msc_iter_bdesc(iter)))
+ iter->wrap_count = 2;
+
+}
+
+static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
+{
+ /* already started, nothing to do */
+ if (iter->start_win)
+ return 0;
+
+ iter->start_win = msc_oldest_window(msc);
+ if (!iter->start_win)
+ return -EINVAL;
+
+ iter->win = iter->start_win;
+ iter->start_block = -1;
+
+ msc_iter_block_start(iter);
+
+ return 0;
+}
+
+static int msc_iter_win_advance(struct msc_iter *iter)
+{
+ iter->win = msc_next_window(iter->win);
+ iter->start_block = -1;
+
+ if (iter->win == iter->start_win) {
+ iter->eof++;
+ return 1;
+ }
+
+ msc_iter_block_start(iter);
+
+ return 0;
+}
+
+static int msc_iter_block_advance(struct msc_iter *iter)
+{
+ iter->block_off = 0;
+
+ /* wrapping */
+ if (iter->wrap_count && iter->block == iter->start_block) {
+ iter->wrap_count--;
+ if (!iter->wrap_count)
+ /* copied newest data from the wrapped block */
+ return msc_iter_win_advance(iter);
+ }
+
+ /* no wrapping, check for last written block */
+ if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
+ /* copied newest data for the window */
+ return msc_iter_win_advance(iter);
+
+ /* block advance */
+ if (++iter->block == iter->win->nr_blocks)
+ iter->block = 0;
+
+ /* no wrapping, sanity check in case there is no last written block */
+ if (!iter->wrap_count && iter->block == iter->start_block)
+ return msc_iter_win_advance(iter);
+
+ return 0;
+}
+
+/**
+ * msc_buffer_iterate() - go through multiblock buffer's data
+ * @iter: iterator structure
+ * @size: amount of data to scan
+ * @data: callback's private data
+ * @fn: iterator callback
+ *
+ * This will start at the window which will be written to next (containing
+ * the oldest data) and work its way to the current window, calling @fn
+ * for each chunk of data as it goes.
+ *
+ * Caller should have msc::user_count reference to make sure the buffer
+ * doesn't disappear from under us.
+ *
+ * Return: amount of data actually scanned.
+ */
+static ssize_t
+msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
+ unsigned long (*fn)(void *, void *, size_t))
+{
+ struct msc *msc = iter->msc;
+ size_t len = size;
+ unsigned int advance;
+
+ if (iter->eof)
+ return 0;
+
+ /* start with the oldest window */
+ if (msc_iter_win_start(iter, msc))
+ return 0;
+
+ do {
+ unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
+ void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
+ size_t tocopy = data_bytes, copied = 0;
+ size_t remaining = 0;
+
+ advance = 1;
+
+ /*
+ * If block wrapping happened, we need to visit the last block
+ * twice, because it contains both the oldest and the newest
+ * data in this window.
+ *
+ * First time (wrap_count==2), in the very beginning, to collect
+ * the oldest data, which is in the range
+ * (data_bytes..DATA_IN_PAGE).
+ *
+ * Second time (wrap_count==1), it's just like any other block,
+ * containing data in the range of [MSC_BDESC..data_bytes].
+ */
+ if (iter->block == iter->start_block && iter->wrap_count) {
+ tocopy = DATA_IN_PAGE - data_bytes;
+ src += data_bytes;
+ }
+
+ if (!tocopy)
+ goto next_block;
+
+ tocopy -= iter->block_off;
+ src += iter->block_off;
+
+ if (len < tocopy) {
+ tocopy = len;
+ advance = 0;
+ }
+
+ remaining = fn(data, src, tocopy);
+
+ if (remaining)
+ advance = 0;
+
+ copied = tocopy - remaining;
+ len -= copied;
+ iter->block_off += copied;
+ iter->offset += copied;
+
+ if (!advance)
+ break;
+
+next_block:
+ if (msc_iter_block_advance(iter))
+ break;
+
+ } while (len);
+
+ return size - len;
+}
+
+/**
+ * msc_buffer_clear_hw_header() - clear hw header for multiblock
+ * @msc: MSC device
+ */
+static void msc_buffer_clear_hw_header(struct msc *msc)
+{
+ struct msc_window *win;
+
+ mutex_lock(&msc->buf_mutex);
+ list_for_each_entry(win, &msc->win_list, entry) {
+ unsigned int blk;
+ size_t hw_sz = sizeof(struct msc_block_desc) -
+ offsetof(struct msc_block_desc, hw_tag);
+
+ for (blk = 0; blk < win->nr_blocks; blk++) {
+ struct msc_block_desc *bdesc = win->block[blk].bdesc;
+
+ memset(&bdesc->hw_tag, 0, hw_sz);
+ }
+ }
+ mutex_unlock(&msc->buf_mutex);
+}
+
+/**
+ * msc_configure() - set up MSC hardware
+ * @msc: the MSC device to configure
+ *
+ * Program storage mode, wrapping, burst length and trace buffer address
+ * into a given MSC. If msc::enabled is set, enable the trace, too.
+ */
+static int msc_configure(struct msc *msc)
+{
+ u32 reg;
+
+ if (msc->mode > MSC_MODE_MULTI)
+ return -ENOTSUPP;
+
+ if (msc->mode == MSC_MODE_MULTI)
+ msc_buffer_clear_hw_header(msc);
+
+ reg = msc->base_addr >> PAGE_SHIFT;
+ iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
+
+ if (msc->mode == MSC_MODE_SINGLE) {
+ reg = msc->nr_pages;
+ iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
+ }
+
+ reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
+ reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
+
+ reg |= msc->mode << __ffs(MSC_MODE);
+ reg |= msc->burst_len << __ffs(MSC_LEN);
+ /*if (msc->mode == MSC_MODE_MULTI)
+ reg |= MSC_RD_HDR_OVRD; */
+ if (msc->wrap)
+ reg |= MSC_WRAPEN;
+ if (msc->enabled)
+ reg |= MSC_EN;
+
+ iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+
+ if (msc->enabled) {
+ msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
+ intel_th_trace_enable(msc->thdev);
+ }
+
+ return 0;
+}
+
+/**
+ * msc_disable() - disable MSC hardware
+ * @msc: MSC device to disable
+ *
+ * If @msc is enabled, disable tracing on the switch and then disable MSC
+ * storage.
+ */
+static void msc_disable(struct msc *msc)
+{
+ unsigned long count;
+ u32 reg;
+
+ if (!msc->enabled)
+ return;
+
+ intel_th_trace_disable(msc->thdev);
+
+ for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
+ count && !(reg & MSCSTS_PLE); count--) {
+ reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
+ cpu_relax();
+ }
+
+ if (!count)
+ dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
+
+ if (msc->mode == MSC_MODE_SINGLE) {
+ msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
+
+ reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
+ msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
+ dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
+ reg, msc->single_sz, msc->single_wrap);
+ }
+
+ reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
+ reg &= ~MSC_EN;
+ iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+ msc->enabled = 0;
+
+ iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
+ iowrite32(0, msc->reg_base + REG_MSU_MSC0SIZE);
+
+ dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
+ ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
+
+ reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
+ dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
+}
+
+static int intel_th_msc_activate(struct intel_th_device *thdev)
+{
+ struct msc *msc = dev_get_drvdata(&thdev->dev);
+ int ret = 0;
+
+ if (!atomic_inc_unless_negative(&msc->user_count))
+ return -ENODEV;
+
+ mutex_lock(&msc->iter_mutex);
+ if (!list_empty(&msc->iter_list))
+ ret = -EBUSY;
+ mutex_unlock(&msc->iter_mutex);
+
+ if (ret) {
+ atomic_dec(&msc->user_count);
+ return ret;
+ }
+
+ msc->enabled = 1;
+
+ return msc_configure(msc);
+}
+
+static void intel_th_msc_deactivate(struct intel_th_device *thdev)
+{
+ struct msc *msc = dev_get_drvdata(&thdev->dev);
+
+ msc_disable(msc);
+
+ atomic_dec(&msc->user_count);
+}
+
+/**
+ * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
+ * @msc: MSC device
+ * @size: allocation size in bytes
+ *
+ * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
+ * caller is expected to hold it.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
+{
+ unsigned int order = get_order(size);
+ struct page *page;
+
+ if (!size)
+ return 0;
+
+ page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+ if (!page)
+ return -ENOMEM;
+
+ split_page(page, order);
+ msc->nr_pages = size >> PAGE_SHIFT;
+ msc->base = page_address(page);
+ msc->base_addr = page_to_phys(page);
+
+ return 0;
+}
+
+/**
+ * msc_buffer_contig_free() - free a contiguous buffer
+ * @msc: MSC configured in SINGLE mode
+ */
+static void msc_buffer_contig_free(struct msc *msc)
+{
+ unsigned long off;
+
+ for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
+ struct page *page = virt_to_page(msc->base + off);
+
+ page->mapping = NULL;
+ __free_page(page);
+ }
+
+ msc->nr_pages = 0;
+}
+
+/**
+ * msc_buffer_contig_get_page() - find a page at a given offset
+ * @msc: MSC configured in SINGLE mode
+ * @pgoff: page offset
+ *
+ * Return: page, if @pgoff is within the range, NULL otherwise.
+ */
+static struct page *msc_buffer_contig_get_page(struct msc *msc,
+ unsigned long pgoff)
+{
+ if (pgoff >= msc->nr_pages)
+ return NULL;
+
+ return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
+}
+
+/**
+ * msc_buffer_win_alloc() - alloc a window for a multiblock mode
+ * @msc: MSC device
+ * @nr_blocks: number of pages in this window
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
+{
+ struct msc_window *win;
+ unsigned long size = PAGE_SIZE;
+ int i, ret = -ENOMEM;
+
+ if (!nr_blocks)
+ return 0;
+
+ win = kzalloc(offsetof(struct msc_window, block[nr_blocks]),
+ GFP_KERNEL);
+ if (!win)
+ return -ENOMEM;
+
+ if (!list_empty(&msc->win_list)) {
+ struct msc_window *prev = list_entry(msc->win_list.prev,
+ struct msc_window, entry);
+
+ win->pgoff = prev->pgoff + prev->nr_blocks;
+ }
+
+ for (i = 0; i < nr_blocks; i++) {
+ win->block[i].bdesc = dma_alloc_coherent(msc_dev(msc), size,
+ &win->block[i].addr,
+ GFP_KERNEL);
+
+#ifdef CONFIG_X86
+ /* Set the page as uncached */
+ set_memory_uc((unsigned long)win->block[i].bdesc, 1);
+#endif
+
+ if (!win->block[i].bdesc)
+ goto err_nomem;
+ }
+
+ win->msc = msc;
+ win->nr_blocks = nr_blocks;
+
+ if (list_empty(&msc->win_list)) {
+ msc->base = win->block[0].bdesc;
+ msc->base_addr = win->block[0].addr;
+ }
+
+ list_add_tail(&win->entry, &msc->win_list);
+ msc->nr_pages += nr_blocks;
+
+ return 0;
+
+err_nomem:
+ for (i--; i >= 0; i--) {
+#ifdef CONFIG_X86
+ /* Reset the page to write-back before releasing */
+ set_memory_wb((unsigned long)win->block[i].bdesc, 1);
+#endif
+ dma_free_coherent(msc_dev(msc), size, win->block[i].bdesc,
+ win->block[i].addr);
+ }
+ kfree(win);
+
+ return ret;
+}
+
+/**
+ * msc_buffer_win_free() - free a window from MSC's window list
+ * @msc: MSC device
+ * @win: window to free
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ */
+static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
+{
+ int i;
+
+ msc->nr_pages -= win->nr_blocks;
+
+ list_del(&win->entry);
+ if (list_empty(&msc->win_list)) {
+ msc->base = NULL;
+ msc->base_addr = 0;
+ }
+
+ for (i = 0; i < win->nr_blocks; i++) {
+ struct page *page = virt_to_page(win->block[i].bdesc);
+
+ page->mapping = NULL;
+#ifdef CONFIG_X86
+ /* Reset the page to write-back before releasing */
+ set_memory_wb((unsigned long)win->block[i].bdesc, 1);
+#endif
+ dma_free_coherent(msc_dev(win->msc), PAGE_SIZE,
+ win->block[i].bdesc, win->block[i].addr);
+ }
+
+ kfree(win);
+}
+
+/**
+ * msc_buffer_relink() - set up block descriptors for multiblock mode
+ * @msc: MSC device
+ *
+ * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
+ * so the caller is expected to hold it.
+ */
+static void msc_buffer_relink(struct msc *msc)
+{
+ struct msc_window *win, *next_win;
+
+ /* call with msc::mutex locked */
+ list_for_each_entry(win, &msc->win_list, entry) {
+ unsigned int blk;
+ u32 sw_tag = 0;
+
+ /*
+ * Last window's next_win should point to the first window
+ * and MSC_SW_TAG_LASTWIN should be set.
+ */
+ if (msc_is_last_win(win)) {
+ sw_tag |= MSC_SW_TAG_LASTWIN;
+ next_win = list_entry(msc->win_list.next,
+ struct msc_window, entry);
+ } else {
+ next_win = list_entry(win->entry.next,
+ struct msc_window, entry);
+ }
+
+ for (blk = 0; blk < win->nr_blocks; blk++) {
+ struct msc_block_desc *bdesc = win->block[blk].bdesc;
+
+ memset(bdesc, 0, sizeof(*bdesc));
+
+ bdesc->next_win = next_win->block[0].addr >> PAGE_SHIFT;
+
+ /*
+ * Similarly to last window, last block should point
+ * to the first one.
+ */
+ if (blk == win->nr_blocks - 1) {
+ sw_tag |= MSC_SW_TAG_LASTBLK;
+ bdesc->next_blk =
+ win->block[0].addr >> PAGE_SHIFT;
+ } else {
+ bdesc->next_blk =
+ win->block[blk + 1].addr >> PAGE_SHIFT;
+ }
+
+ bdesc->sw_tag = sw_tag;
+ bdesc->block_sz = PAGE_SIZE / 64;
+ }
+ }
+
+ /*
+ * Make the above writes globally visible before tracing is
+ * enabled to make sure hardware sees them coherently.
+ */
+ wmb();
+}
+
+static void msc_buffer_multi_free(struct msc *msc)
+{
+ struct msc_window *win, *iter;
+
+ list_for_each_entry_safe(win, iter, &msc->win_list, entry)
+ msc_buffer_win_free(msc, win);
+}
+
+static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
+ unsigned int nr_wins)
+{
+ int ret, i;
+
+ for (i = 0; i < nr_wins; i++) {
+ ret = msc_buffer_win_alloc(msc, nr_pages[i]);
+ if (ret) {
+ msc_buffer_multi_free(msc);
+ return ret;
+ }
+ }
+
+ msc_buffer_relink(msc);
+
+ return 0;
+}
+
+/**
+ * msc_buffer_free() - free buffers for MSC
+ * @msc: MSC device
+ *
+ * Free MSC's storage buffers.
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
+ * serialize, so the caller is expected to hold it.
+ */
+static void msc_buffer_free(struct msc *msc)
+{
+ if (msc->mode == MSC_MODE_SINGLE)
+ msc_buffer_contig_free(msc);
+ else if (msc->mode == MSC_MODE_MULTI)
+ msc_buffer_multi_free(msc);
+}
+
+/**
+ * msc_buffer_alloc() - allocate a buffer for MSC
+ * @msc: MSC device
+ * @size: allocation size in bytes
+ *
+ * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
+ * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
+ * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
+ * window per invocation, so in multiblock mode this can be called multiple
+ * times for the same MSC to allocate multiple windows.
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
+ unsigned int nr_wins)
+{
+ int ret;
+
+ /* -1: buffer not allocated */
+ if (atomic_read(&msc->user_count) != -1)
+ return -EBUSY;
+
+ if (msc->mode == MSC_MODE_SINGLE) {
+ if (nr_wins != 1)
+ return -EINVAL;
+
+ ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
+ } else if (msc->mode == MSC_MODE_MULTI) {
+ ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
+ } else {
+ ret = -ENOTSUPP;
+ }
+
+ if (!ret) {
+ /* allocation should be visible before the counter goes to 0 */
+ smp_mb__before_atomic();
+
+ if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
+ return -EINVAL;
+ }
+
+ return ret;
+}
+
+/**
+ * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
+ * @msc: MSC device
+ *
+ * This will free MSC buffer unless it is in use or there is no allocated
+ * buffer.
+ * Caller needs to hold msc::buf_mutex.
+ *
+ * Return: 0 on successful deallocation or if there was no buffer to
+ * deallocate, -EBUSY if there are active users.
+ */
+static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
+{
+ int count, ret = 0;
+
+ count = atomic_cmpxchg(&msc->user_count, 0, -1);
+
+ /* > 0: buffer is allocated and has users */
+ if (count > 0)
+ ret = -EBUSY;
+ /* 0: buffer is allocated, no users */
+ else if (!count)
+ msc_buffer_free(msc);
+ /* < 0: no buffer, nothing to do */
+
+ return ret;
+}
+
+/**
+ * msc_buffer_free_unless_used() - free a buffer unless it's in use
+ * @msc: MSC device
+ *
+ * This is a locked version of msc_buffer_unlocked_free_unless_used().
+ */
+static int msc_buffer_free_unless_used(struct msc *msc)
+{
+ int ret;
+
+ mutex_lock(&msc->buf_mutex);
+ ret = msc_buffer_unlocked_free_unless_used(msc);
+ mutex_unlock(&msc->buf_mutex);
+
+ return ret;
+}
+
+/**
+ * msc_buffer_get_page() - get MSC buffer page at a given offset
+ * @msc: MSC device
+ * @pgoff: page offset into the storage buffer
+ *
+ * This traverses msc::win_list, so holding msc::buf_mutex is expected from
+ * the caller.
+ *
+ * Return: page if @pgoff corresponds to a valid buffer page or NULL.
+ */
+static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
+{
+ struct msc_window *win;
+
+ if (msc->mode == MSC_MODE_SINGLE)
+ return msc_buffer_contig_get_page(msc, pgoff);
+
+ list_for_each_entry(win, &msc->win_list, entry)
+ if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
+ goto found;
+
+ return NULL;
+
+found:
+ pgoff -= win->pgoff;
+ return virt_to_page(win->block[pgoff].bdesc);
+}
+
+/**
+ * struct msc_win_to_user_struct - data for copy_to_user() callback
+ * @buf: userspace buffer to copy data to
+ * @offset: running offset
+ */
+struct msc_win_to_user_struct {
+ char __user *buf;
+ unsigned long offset;
+};
+
+/**
+ * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
+ * @data: callback's private data
+ * @src: source buffer
+ * @len: amount of data to copy from the source buffer
+ */
+static unsigned long msc_win_to_user(void *data, void *src, size_t len)
+{
+ struct msc_win_to_user_struct *u = data;
+ unsigned long ret;
+
+ ret = copy_to_user(u->buf + u->offset, src, len);
+ u->offset += len - ret;
+
+ return ret;
+}
+
+
+/*
+ * file operations' callbacks
+ */
+
+static int intel_th_msc_open(struct inode *inode, struct file *file)
+{
+ struct intel_th_device *thdev = file->private_data;
+ struct msc *msc = dev_get_drvdata(&thdev->dev);
+ struct msc_iter *iter;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ iter = msc_iter_install(msc);
+ if (!iter)
+ return -ENOMEM;
+
+ file->private_data = iter;
+
+ return nonseekable_open(inode, file);
+}
+
+static int intel_th_msc_release(struct inode *inode, struct file *file)
+{
+ struct msc_iter *iter = file->private_data;
+ struct msc *msc = iter->msc;
+
+ msc_iter_remove(iter, msc);
+
+ return 0;
+}
+
+static ssize_t
+msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
+{
+ unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
+ unsigned long start = off, tocopy = 0;
+
+ if (msc->single_wrap) {
+ start += msc->single_sz;
+ if (start < size) {
+ tocopy = min(rem, size - start);
+ if (copy_to_user(buf, msc->base + start, tocopy))
+ return -EFAULT;
+
+ buf += tocopy;
+ rem -= tocopy;
+ start += tocopy;
+ }
+
+ start &= size - 1;
+ if (rem) {
+ tocopy = min(rem, msc->single_sz - start);
+ if (copy_to_user(buf, msc->base + start, tocopy))
+ return -EFAULT;
+
+ rem -= tocopy;
+ }
+
+ return len - rem;
+ }
+
+ if (copy_to_user(buf, msc->base + start, rem))
+ return -EFAULT;
+
+ return len;
+}
+
+static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ struct msc_iter *iter = file->private_data;
+ struct msc *msc = iter->msc;
+ size_t size;
+ loff_t off = *ppos;
+ ssize_t ret = 0;
+
+ if (!atomic_inc_unless_negative(&msc->user_count))
+ return 0;
+
+ if (msc->enabled) {
+ ret = -EBUSY;
+ goto put_count;
+ }
+
+ if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
+ size = msc->single_sz;
+ else
+ size = msc->nr_pages << PAGE_SHIFT;
+
+ if (!size)
+ return 0;
+
+ if (off >= size) {
+ len = 0;
+ goto put_count;
+ }
+ if (off + len >= size)
+ len = size - off;
+
+ if (msc->mode == MSC_MODE_SINGLE) {
+ ret = msc_single_to_user(msc, buf, off, len);
+ if (ret >= 0)
+ *ppos += ret;
+ } else if (msc->mode == MSC_MODE_MULTI) {
+ struct msc_win_to_user_struct u = {
+ .buf = buf,
+ .offset = 0,
+ };
+
+ ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
+ if (ret >= 0)
+ *ppos = iter->offset;
+ } else {
+ ret = -ENOTSUPP;
+ }
+
+put_count:
+ atomic_dec(&msc->user_count);
+
+ return ret;
+}
+
+/*
+ * vm operations callbacks (vm_ops)
+ */
+
+static void msc_mmap_open(struct vm_area_struct *vma)
+{
+ struct msc_iter *iter = vma->vm_file->private_data;
+ struct msc *msc = iter->msc;
+
+ atomic_inc(&msc->mmap_count);
+}
+
+static void msc_mmap_close(struct vm_area_struct *vma)
+{
+ struct msc_iter *iter = vma->vm_file->private_data;
+ struct msc *msc = iter->msc;
+ unsigned long pg;
+
+ if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
+ return;
+
+ /* drop page _counts */
+ for (pg = 0; pg < msc->nr_pages; pg++) {
+ struct page *page = msc_buffer_get_page(msc, pg);
+
+ if (WARN_ON_ONCE(!page))
+ continue;
+
+ if (page->mapping)
+ page->mapping = NULL;
+ }
+
+ /* last mapping -- drop user_count */
+ atomic_dec(&msc->user_count);
+ mutex_unlock(&msc->buf_mutex);
+}
+
+static int msc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct msc_iter *iter = vma->vm_file->private_data;
+ struct msc *msc = iter->msc;
+
+ vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
+ if (!vmf->page)
+ return VM_FAULT_SIGBUS;
+
+ get_page(vmf->page);
+ vmf->page->mapping = vma->vm_file->f_mapping;
+ vmf->page->index = vmf->pgoff;
+
+ return 0;
+}
+
+static const struct vm_operations_struct msc_mmap_ops = {
+ .open = msc_mmap_open,
+ .close = msc_mmap_close,
+ .fault = msc_mmap_fault,
+};
+
+static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ unsigned long size = vma->vm_end - vma->vm_start;
+ struct msc_iter *iter = vma->vm_file->private_data;
+ struct msc *msc = iter->msc;
+ int ret = -EINVAL;
+
+ if (!size || offset_in_page(size))
+ return -EINVAL;
+
+ if (vma->vm_pgoff)
+ return -EINVAL;
+
+ /* grab user_count once per mmap; drop in msc_mmap_close() */
+ if (!atomic_inc_unless_negative(&msc->user_count))
+ return -EINVAL;
+
+ if (msc->mode != MSC_MODE_SINGLE &&
+ msc->mode != MSC_MODE_MULTI)
+ goto out;
+
+ if (size >> PAGE_SHIFT != msc->nr_pages)
+ goto out;
+
+ atomic_set(&msc->mmap_count, 1);
+ ret = 0;
+
+out:
+ if (ret)
+ atomic_dec(&msc->user_count);
+
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY;
+ vma->vm_ops = &msc_mmap_ops;
+ return ret;
+}
+
+static const struct file_operations intel_th_msc_fops = {
+ .open = intel_th_msc_open,
+ .release = intel_th_msc_release,
+ .read = intel_th_msc_read,
+ .mmap = intel_th_msc_mmap,
+ .llseek = no_llseek,
+};
+
+static int intel_th_msc_init(struct msc *msc)
+{
+ atomic_set(&msc->user_count, -1);
+
+ msc->mode = MSC_MODE_MULTI;
+ mutex_init(&msc->buf_mutex);
+ INIT_LIST_HEAD(&msc->win_list);
+
+ mutex_init(&msc->iter_mutex);
+ INIT_LIST_HEAD(&msc->iter_list);
+
+ msc->burst_len =
+ (ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
+ __ffs(MSC_LEN);
+
+ return 0;
+}
+
+static const char * const msc_mode[] = {
+ [MSC_MODE_SINGLE] = "single",
+ [MSC_MODE_MULTI] = "multi",
+ [MSC_MODE_EXI] = "ExI",
+ [MSC_MODE_DEBUG] = "debug",
+};
+
+static ssize_t
+wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
+}
+
+static ssize_t
+wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
+ size_t size)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+ unsigned long val;
+ int ret;
+
+ ret = kstrtoul(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ msc->wrap = !!val;
+
+ return size;
+}
+
+static DEVICE_ATTR_RW(wrap);
+
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%s\n", msc_mode[msc->mode]);
+}
+
+static ssize_t
+mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
+ size_t size)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+ size_t len = size;
+ char *cp;
+ int i, ret;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ cp = memchr(buf, '\n', len);
+ if (cp)
+ len = cp - buf;
+
+ for (i = 0; i < ARRAY_SIZE(msc_mode); i++)
+ if (!strncmp(msc_mode[i], buf, len))
+ goto found;
+
+ return -EINVAL;
+
+found:
+ mutex_lock(&msc->buf_mutex);
+ ret = msc_buffer_unlocked_free_unless_used(msc);
+ if (!ret)
+ msc->mode = i;
+ mutex_unlock(&msc->buf_mutex);
+
+ return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(mode);
+
+static ssize_t
+nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+ struct msc_window *win;
+ size_t count = 0;
+
+ mutex_lock(&msc->buf_mutex);
+
+ if (msc->mode == MSC_MODE_SINGLE)
+ count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
+ else if (msc->mode == MSC_MODE_MULTI) {
+ list_for_each_entry(win, &msc->win_list, entry) {
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "%d%c", win->nr_blocks,
+ msc_is_last_win(win) ? '\n' : ',');
+ }
+ } else {
+ count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
+ }
+
+ mutex_unlock(&msc->buf_mutex);
+
+ return count;
+}
+
+static ssize_t
+nr_pages_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct msc *msc = dev_get_drvdata(dev);
+ unsigned long val, *win = NULL, *rewin;
+ size_t len = size;
+ const char *p = buf;
+ char *end, *s;
+ int ret, nr_wins = 0;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ ret = msc_buffer_free_unless_used(msc);
+ if (ret)
+ return ret;
+
+ /* scan the comma-separated list of allocation sizes */
+ end = memchr(buf, '\n', len);
+ if (end)
+ len = end - buf;
+
+ do {
+ end = memchr(p, ',', len);
+ s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
+ ret = kstrtoul(s, 10, &val);
+ kfree(s);
+
+ if (ret || !val)
+ goto free_win;
+
+ if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
+ ret = -EINVAL;
+ goto free_win;
+ }
+
+ nr_wins++;
+ rewin = krealloc(win, sizeof(*win) * nr_wins, GFP_KERNEL);
+ if (!rewin) {
+ kfree(win);
+ return -ENOMEM;
+ }
+
+ win = rewin;
+ win[nr_wins - 1] = val;
+
+ if (!end)
+ break;
+
+ len -= end - p;
+ p = end + 1;
+ } while (len);
+
+ mutex_lock(&msc->buf_mutex);
+ ret = msc_buffer_alloc(msc, win, nr_wins);
+ mutex_unlock(&msc->buf_mutex);
+
+free_win:
+ kfree(win);
+
+ return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(nr_pages);
+
+static struct attribute *msc_output_attrs[] = {
+ &dev_attr_wrap.attr,
+ &dev_attr_mode.attr,
+ &dev_attr_nr_pages.attr,
+ NULL,
+};
+
+static struct attribute_group msc_output_group = {
+ .attrs = msc_output_attrs,
+};
+
+static int intel_th_msc_probe(struct intel_th_device *thdev)
+{
+ struct device *dev = &thdev->dev;
+ struct resource *res;
+ struct msc *msc;
+ void __iomem *base;
+ int err;
+
+ res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ base = devm_ioremap(dev, res->start, resource_size(res));
+ if (!base)
+ return -ENOMEM;
+
+ msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
+ if (!msc)
+ return -ENOMEM;
+
+ msc->index = thdev->id;
+
+ msc->thdev = thdev;
+ msc->reg_base = base + msc->index * 0x100;
+
+ err = intel_th_msc_init(msc);
+ if (err)
+ return err;
+
+ err = sysfs_create_group(&dev->kobj, &msc_output_group);
+ if (err)
+ return err;
+
+ dev_set_drvdata(dev, msc);
+
+ return 0;
+}
+
+static void intel_th_msc_remove(struct intel_th_device *thdev)
+{
+ sysfs_remove_group(&thdev->dev.kobj, &msc_output_group);
+}
+
+static struct intel_th_driver intel_th_msc_driver = {
+ .probe = intel_th_msc_probe,
+ .remove = intel_th_msc_remove,
+ .activate = intel_th_msc_activate,
+ .deactivate = intel_th_msc_deactivate,
+ .fops = &intel_th_msc_fops,
+ .driver = {
+ .name = "msc",
+ .owner = THIS_MODULE,
+ },
+};
+
+module_driver(intel_th_msc_driver,
+ intel_th_driver_register,
+ intel_th_driver_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
Code Review / kvmfornfv.git / blobdiff