diff options
Diffstat (limited to 'drivers/hwtracing/intel_th/msu.c')
| -rw-r--r-- | drivers/hwtracing/intel_th/msu.c | 1509 |
1 files changed, 1509 insertions, 0 deletions
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c new file mode 100644 index 000000000000..99f7662e27f1 --- /dev/null +++ b/drivers/hwtracing/intel_th/msu.c @@ -0,0 +1,1509 @@ +/* + * 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) +{ + size_t 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 (IS_ERR(base)) + return PTR_ERR(base); + + 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>"); |