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Message-ID: <2023061542-reformed-unholy-10a3@gregkh>
Date: Thu, 15 Jun 2023 12:33:33 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
Cc: Andy Gross <agross@...nel.org>,
Konrad Dybcio <konrad.dybcio@...ainline.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Bjorn Andersson <andersson@...nel.org>,
Rob Herring <robh+dt@...nel.org>, Alex Elder <elder@...e.org>,
Arnd Bergmann <arnd@...db.de>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
Sibi Sankar <quic_sibis@...cinc.com>,
Rajendra Nayak <quic_rjendra@...cinc.com>
Subject: Re: [PATCH V23 2/3] misc: dcc: Add driver support for Data Capture
and Compare unit(DCC)
On Thu, May 04, 2023 at 11:36:22PM -0700, Souradeep Chowdhury wrote:
> +/**
> + * struct dcc_config_entry - configuration information related to each dcc instruction
> + * @base: Base address of the register to be configured in dcc
Why is this a u32 and not a bigger size?
> + * @offset: Offset to the base address to be configured in dcc
> + * @len: Length of the address in words to be configured in dcc
What is a "word" here, 16 bits?
> + * @loop_cnt: The number of times to loop on the register address in case
> + of loop instructions
> + * @write_val: The value to be written on the register address in case of
> + write instructions
> + * @mask: Mask corresponding to the value to be written in case of
> + write instructions
> + * @apb_bus: Type of bus to be used for the instruction, can be either
> + 'apb' or 'ahb'
How can a bool be either "apb" or "ahb"?
> + * @desc_type: Stores the type of dcc instruction
> + * @list: This is used to append this instruction to the list of
> + instructions
> + */
> +struct dcc_config_entry {
> + u32 base;
> + u32 offset;
> + u32 len;
> + u32 loop_cnt;
> + u32 write_val;
> + u32 mask;
> + bool apb_bus;
> + enum dcc_descriptor_type desc_type;
> + struct list_head list;
> +};
> +
> +/**
> + * struct dcc_drvdata - configuration information related to a dcc device
> + * @base: Base Address of the dcc device
> + * @dev: The device attached to the driver data
> + * @mutex: Lock to protect access and manipulation of dcc_drvdata
> + * @ram_base: Base address for the SRAM dedicated for the dcc device
> + * @ram_size: Total size of the SRAM dedicated for the dcc device
> + * @ram_offset: Offset to the SRAM dedicated for dcc device
> + * @mem_map_ver: Memory map version of DCC hardware
> + * @ram_cfg: Used for address limit calculation for dcc
> + * @ram_start: Starting address of DCC SRAM
> + * @sram_dev: Miscellaneous device equivalent of dcc SRAM
> + * @cfg_head: Points to the head of the linked list of addresses
> + * @dbg_dir: The dcc debugfs directory under which all the debugfs files are placed
> + * @nr_link_list: Total number of linkedlists supported by the DCC configuration
> + * @loop_shift: Loop offset bits range for the addresses
> + * @enable_bitmap: Bitmap to capture the enabled status of each linked list of addresses
You use a pointer for a bitmap?
> + */
> +struct dcc_drvdata {
> + void __iomem *base;
> + void __iomem *ram_base;
> + struct device *dev;
> + struct mutex mutex;
> + size_t ram_size;
> + size_t ram_offset;
> + int mem_map_ver;
u64?
> + unsigned int ram_cfg;
> + unsigned int ram_start;
> + struct miscdevice sram_dev;
> + struct list_head *cfg_head;
> + struct dentry *dbg_dir;
> + size_t nr_link_list;
"nr"?
> + u8 loop_shift;
> + unsigned long *enable_bitmap;
> +};
> +
> +struct dcc_cfg_attr {
> + u32 addr;
> + u32 prev_addr;
> + u32 prev_off;
> + u32 link;
> + u32 sram_offset;
> +};
> +
> +struct dcc_cfg_loop_attr {
> + u32 loop_cnt;
> + u32 loop_len;
> + u32 loop_off;
> + bool loop_start;
> +};
> +
> +static inline u32 dcc_status(int version)
> +{
> + return version == 1 ? 0x0c : 0x1c;
> +}
> +
> +static inline u32 dcc_list_offset(int version)
> +{
> + if (version == 1)
> + return 0x1c;
> + else if (version == 2)
> + return 0x2c;
> + else
> + return 0x34;
> +}
> +
> +static inline void dcc_list_writel(struct dcc_drvdata *drvdata,
> + u32 ll, u32 val, u32 off)
> +{
> + u32 offset = dcc_list_offset(drvdata->mem_map_ver) + off;
> +
> + writel(val, drvdata->base + ll * DCC_LL_OFFSET + offset);
> +}
> +
> +static inline u32 dcc_list_readl(struct dcc_drvdata *drvdata, u32 ll, u32 off)
> +{
> + u32 offset = dcc_list_offset(drvdata->mem_map_ver) + off;
> +
> + return readl(drvdata->base + ll * DCC_LL_OFFSET + offset);
> +}
> +
> +static void dcc_sram_write_auto(struct dcc_drvdata *drvdata,
> + u32 val, u32 *off)
> +{
> + /* If the overflow condition is met increment the offset
> + * and return to indicate that overflow has occurred
> + */
> + if (unlikely(*off > drvdata->ram_size - 4)) {
If you can not measure the difference in userspace when using
likely/unlikely, then never use it as the compiler and CPU will do it
better for you.
> + *off += 4;
> + return;
> + }
> +
> + writel(val, drvdata->ram_base + *off);
> +
> + *off += 4;
> +}
> +
> +static int dcc_sw_trigger(struct dcc_drvdata *drvdata)
> +{
> + void __iomem *addr;
> + int i;
> + u32 status;
> + u32 ll_cfg;
> + u32 tmp_ll_cfg;
> + u32 val;
> + int ret = 0;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + for (i = 0; i < drvdata->nr_link_list; i++) {
> + if (!test_bit(i, drvdata->enable_bitmap))
> + continue;
> + ll_cfg = dcc_list_readl(drvdata, i, DCC_LL_CFG);
> + tmp_ll_cfg = ll_cfg & ~DCC_TRIGGER_MASK;
> + dcc_list_writel(drvdata, tmp_ll_cfg, i, DCC_LL_CFG);
> + dcc_list_writel(drvdata, 1, i, DCC_LL_SW_TRIGGER);
> + dcc_list_writel(drvdata, ll_cfg, i, DCC_LL_CFG);
> + }
> +
> + addr = drvdata->base + dcc_status(drvdata->mem_map_ver);
> + if (readl_poll_timeout(addr, val, !FIELD_GET(DCC_STATUS_MASK, val),
> + 1, STATUS_READY_TIMEOUT)) {
> + dev_err(drvdata->dev, "DCC is busy after receiving sw trigger\n");
> + ret = -EBUSY;
> + goto out_unlock;
> + }
> +
> + for (i = 0; i < drvdata->nr_link_list; i++) {
> + if (!test_bit(i, drvdata->enable_bitmap))
> + continue;
> +
> + status = dcc_list_readl(drvdata, i, DCC_LL_BUS_ACCESS_STATUS);
> + if (!status)
> + continue;
> +
> + dev_err(drvdata->dev, "Read access error for list %d err: 0x%x\n",
> + i, status);
> + ll_cfg = dcc_list_readl(drvdata, i, DCC_LL_CFG);
> + tmp_ll_cfg = ll_cfg & ~DCC_TRIGGER_MASK;
> + dcc_list_writel(drvdata, tmp_ll_cfg, i, DCC_LL_CFG);
> + dcc_list_writel(drvdata, DCC_STATUS_MASK, i, DCC_LL_BUS_ACCESS_STATUS);
> + dcc_list_writel(drvdata, ll_cfg, i, DCC_LL_CFG);
> + ret = -ENODATA;
> + break;
> + }
> +
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> + return ret;
> +}
> +
> +static void dcc_ll_cfg_reset_link(struct dcc_cfg_attr *cfg)
> +{
> + cfg->addr = 0x00;
> + cfg->link = 0;
> + cfg->prev_off = 0;
> + cfg->prev_addr = cfg->addr;
> +}
> +
> +static void dcc_emit_read_write(struct dcc_drvdata *drvdata,
> + struct dcc_config_entry *entry,
> + struct dcc_cfg_attr *cfg)
> +{
> + if (cfg->link) {
> + /*
> + * write new offset = 1 to continue
> + * processing the list
> + */
> +
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> +
> + /* Reset link and prev_off */
> + dcc_ll_cfg_reset_link(cfg);
> + }
> +
> + cfg->addr = DCC_RD_MOD_WR_DESCRIPTOR;
> + dcc_sram_write_auto(drvdata, cfg->addr, &cfg->sram_offset);
> +
> + dcc_sram_write_auto(drvdata, entry->mask, &cfg->sram_offset);
> +
> + dcc_sram_write_auto(drvdata, entry->write_val, &cfg->sram_offset);
> +
> + cfg->addr = 0;
> +}
> +
> +static void dcc_emit_loop(struct dcc_drvdata *drvdata, struct dcc_config_entry *entry,
> + struct dcc_cfg_attr *cfg,
> + struct dcc_cfg_loop_attr *cfg_loop,
> + u32 *total_len)
> +{
> + int loop;
> +
> + /* Check if we need to write link of prev entry */
> + if (cfg->link)
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> +
> + if (cfg_loop->loop_start) {
> + loop = (cfg->sram_offset - cfg_loop->loop_off) / 4;
> + loop |= (cfg_loop->loop_cnt << drvdata->loop_shift) &
> + GENMASK(DCC_ADDR_LIMIT, drvdata->loop_shift);
> + loop |= DCC_LOOP_DESCRIPTOR;
> + *total_len += (*total_len - cfg_loop->loop_len) * cfg_loop->loop_cnt;
> +
> + dcc_sram_write_auto(drvdata, loop, &cfg->sram_offset);
> +
> + cfg_loop->loop_start = false;
> + cfg_loop->loop_len = 0;
> + cfg_loop->loop_off = 0;
> + } else {
> + cfg_loop->loop_start = true;
> + cfg_loop->loop_cnt = entry->loop_cnt - 1;
> + cfg_loop->loop_len = *total_len;
> + cfg_loop->loop_off = cfg->sram_offset;
> + }
> +
> + /* Reset link and prev_off */
> + dcc_ll_cfg_reset_link(cfg);
> +}
> +
> +static void dcc_emit_write(struct dcc_drvdata *drvdata,
> + struct dcc_config_entry *entry,
> + struct dcc_cfg_attr *cfg)
> +{
> + u32 off;
> +
> + if (cfg->link) {
> + /*
> + * write new offset = 1 to continue
> + * processing the list
> + */
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> +
> + /* Reset link and prev_off */
> + cfg->addr = 0x00;
> + cfg->prev_off = 0;
> + cfg->prev_addr = cfg->addr;
> + }
> +
> + off = entry->offset / 4;
> + /* write new offset-length pair to correct position */
> + cfg->link |= ((off & DCC_WRITE_OFF_MASK) | DCC_WRITE_MASK |
> + FIELD_PREP(DCC_WRITE_LEN_MASK, entry->len));
> + cfg->link |= DCC_LINK_DESCRIPTOR;
> +
> + /* Address type */
> + cfg->addr = (entry->base >> 4) & GENMASK(DCC_ADDR_LIMIT, 0);
> + if (entry->apb_bus)
> + cfg->addr |= DCC_ADDR_DESCRIPTOR | DCC_WRITE_IND | DCC_APB_IND;
> + else
> + cfg->addr |= DCC_ADDR_DESCRIPTOR | DCC_WRITE_IND | DCC_AHB_IND;
> + dcc_sram_write_auto(drvdata, cfg->addr, &cfg->sram_offset);
> +
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> +
> + dcc_sram_write_auto(drvdata, entry->write_val, &cfg->sram_offset);
> +
> + cfg->addr = 0x00;
> + cfg->link = 0;
> +}
> +
> +static int dcc_emit_read(struct dcc_drvdata *drvdata,
> + struct dcc_config_entry *entry,
> + struct dcc_cfg_attr *cfg,
> + u32 *pos, u32 *total_len)
> +{
> + u32 off;
> + u32 temp_off;
> +
> + cfg->addr = (entry->base >> 4) & GENMASK(27, 0);
> +
> + if (entry->apb_bus)
> + cfg->addr |= DCC_ADDR_DESCRIPTOR | DCC_READ_IND | DCC_APB_IND;
> + else
> + cfg->addr |= DCC_ADDR_DESCRIPTOR | DCC_READ_IND | DCC_AHB_IND;
> +
> + off = entry->offset / 4;
> +
> + *total_len += entry->len * 4;
> +
> + if (!cfg->prev_addr || cfg->prev_addr != cfg->addr || cfg->prev_off > off) {
> + /* Check if we need to write prev link entry */
> + if (cfg->link)
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> + dev_dbg(drvdata->dev, "DCC: sram address 0x%x\n", cfg->sram_offset);
> +
> + /* Write address */
> + dcc_sram_write_auto(drvdata, cfg->addr, &cfg->sram_offset);
> +
> + /* Reset link and prev_off */
> + cfg->link = 0;
> + cfg->prev_off = 0;
> + }
> +
> + if ((off - cfg->prev_off) > 0xff || entry->len > MAX_DCC_LEN) {
> + dev_err(drvdata->dev, "DCC: Programming error Base: 0x%x, offset 0x%x\n",
> + entry->base, entry->offset);
> + return -EINVAL;
> + }
> +
> + if (cfg->link) {
> + /*
> + * link already has one offset-length so new
> + * offset-length needs to be placed at
> + * bits [29:15]
> + */
> + *pos = 15;
> +
> + /* Clear bits [31:16] */
> + cfg->link &= GENMASK(14, 0);
> + } else {
> + /*
> + * link is empty, so new offset-length needs
> + * to be placed at bits [15:0]
> + */
> + *pos = 0;
> + cfg->link = 1 << 15;
> + }
> +
> + /* write new offset-length pair to correct position */
> + temp_off = (off - cfg->prev_off) & GENMASK(7, 0);
> + cfg->link |= temp_off | ((entry->len << 8) & GENMASK(14, 8)) << *pos;
> +
> + cfg->link |= DCC_LINK_DESCRIPTOR;
> +
> + if (*pos) {
> + dcc_sram_write_auto(drvdata, cfg->link, &cfg->sram_offset);
> + cfg->link = 0;
> + }
> +
> + cfg->prev_off = off + entry->len - 1;
> + cfg->prev_addr = cfg->addr;
> + return 0;
> +}
> +
> +static int dcc_emit_config(struct dcc_drvdata *drvdata, unsigned int curr_list)
> +{
> + int ret;
> + u32 total_len, pos;
> + struct dcc_config_entry *entry;
> + struct dcc_cfg_attr cfg = {0};
> + struct dcc_cfg_loop_attr cfg_loop = {0};
> +
> + cfg.sram_offset = drvdata->ram_cfg * 4;
> + total_len = 0;
> +
> + list_for_each_entry(entry, &drvdata->cfg_head[curr_list], list) {
> + switch (entry->desc_type) {
> + case DCC_READ_WRITE_TYPE:
> + dcc_emit_read_write(drvdata, entry, &cfg);
> + break;
> +
> + case DCC_LOOP_TYPE:
> + dcc_emit_loop(drvdata, entry, &cfg, &cfg_loop, &total_len);
> + break;
> +
> + case DCC_WRITE_TYPE:
> + dcc_emit_write(drvdata, entry, &cfg);
> + break;
> +
> + case DCC_READ_TYPE:
> + ret = dcc_emit_read(drvdata, entry, &cfg, &pos, &total_len);
> + if (ret)
> + goto err;
> + break;
> + }
> + }
> +
> + if (cfg.link)
> + dcc_sram_write_auto(drvdata, cfg.link, &cfg.sram_offset);
> +
> + if (cfg_loop.loop_start) {
> + dev_err(drvdata->dev, "DCC: Programming error: Loop unterminated\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + /* Handling special case of list ending with a rd_mod_wr */
> + if (cfg.addr == DCC_RD_MOD_WR_DESCRIPTOR) {
> + cfg.addr = (DCC_RD_MOD_WR_ADDR) & GENMASK(27, 0);
> + cfg.addr |= DCC_ADDR_DESCRIPTOR;
> + dcc_sram_write_auto(drvdata, cfg.addr, &cfg.sram_offset);
> + }
> +
> + /* Setting zero to indicate end of the list */
> + cfg.link = DCC_LINK_DESCRIPTOR;
> + dcc_sram_write_auto(drvdata, cfg.link, &cfg.sram_offset);
> +
> + /* Check if sram offset exceeds the ram size */
> + if (cfg.sram_offset > drvdata->ram_size)
> + goto overstep;
> +
> + /* Update ram_cfg and check if the data will overstep */
> + drvdata->ram_cfg = (cfg.sram_offset + total_len) / 4;
> +
> + if (cfg.sram_offset + total_len > drvdata->ram_size) {
> + cfg.sram_offset += total_len;
> + goto overstep;
> + }
> +
> + drvdata->ram_start = cfg.sram_offset / 4;
> + return 0;
> +overstep:
> + ret = -EINVAL;
> + memset_io(drvdata->ram_base, 0, drvdata->ram_size);
> +
> +err:
> + return ret;
> +}
> +
> +static bool dcc_valid_list(struct dcc_drvdata *drvdata, unsigned int curr_list)
> +{
> + u32 lock_reg;
> +
> + if (list_empty(&drvdata->cfg_head[curr_list]))
> + return false;
> +
> + if (test_bit(curr_list, drvdata->enable_bitmap)) {
> + dev_err(drvdata->dev, "List %d is already enabled\n", curr_list);
> + return false;
> + }
> +
> + lock_reg = dcc_list_readl(drvdata, curr_list, DCC_LL_LOCK);
> + if (lock_reg & DCC_LOCK_MASK) {
> + dev_err(drvdata->dev, "List %d is already locked\n", curr_list);
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static bool is_dcc_enabled(struct dcc_drvdata *drvdata)
> +{
> + int list;
> +
> + for (list = 0; list < drvdata->nr_link_list; list++)
> + if (test_bit(list, drvdata->enable_bitmap))
> + return true;
> +
> + return false;
> +}
> +
> +static int dcc_enable(struct dcc_drvdata *drvdata, unsigned int curr_list)
> +{
> + int ret;
> + u32 ram_cfg_base;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + if (!dcc_valid_list(drvdata, curr_list)) {
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> +
> + /* Fill dcc sram with the poison value.
> + * This helps in understanding bus
> + * hang from registers returning a zero
> + */
> + if (!is_dcc_enabled(drvdata))
> + memset_io(drvdata->ram_base, 0xde, drvdata->ram_size);
> +
> + /* 1. Take ownership of the list */
> + dcc_list_writel(drvdata, DCC_LOCK_MASK, curr_list, DCC_LL_LOCK);
> +
> + /* 2. Program linked-list in the SRAM */
> + ram_cfg_base = drvdata->ram_cfg;
> + ret = dcc_emit_config(drvdata, curr_list);
> + if (ret) {
> + dcc_list_writel(drvdata, 0, curr_list, DCC_LL_LOCK);
> + goto out_unlock;
> + }
> +
> + /* 3. Program DCC_RAM_CFG reg */
> + dcc_list_writel(drvdata, ram_cfg_base +
> + drvdata->ram_offset / 4, curr_list, DCC_LL_BASE);
> + dcc_list_writel(drvdata, drvdata->ram_start +
> + drvdata->ram_offset / 4, curr_list, DCC_FD_BASE);
> + dcc_list_writel(drvdata, 0xFFF, curr_list, DCC_LL_TIMEOUT);
> +
> + /* 4. Clears interrupt status register */
> + dcc_list_writel(drvdata, 0, curr_list, DCC_LL_INT_ENABLE);
> + dcc_list_writel(drvdata, (BIT(0) | BIT(1) | BIT(2)),
> + curr_list, DCC_LL_INT_STATUS);
> +
> + set_bit(curr_list, drvdata->enable_bitmap);
> +
> + /* 5. Configure trigger */
> + dcc_list_writel(drvdata, DCC_TRIGGER_MASK,
> + curr_list, DCC_LL_CFG);
> +
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> + return ret;
> +}
> +
> +static void dcc_disable(struct dcc_drvdata *drvdata, int curr_list)
> +{
> + mutex_lock(&drvdata->mutex);
> +
> + if (!test_bit(curr_list, drvdata->enable_bitmap))
> + goto out_unlock;
> + dcc_list_writel(drvdata, 0, curr_list, DCC_LL_CFG);
> + dcc_list_writel(drvdata, 0, curr_list, DCC_LL_BASE);
> + dcc_list_writel(drvdata, 0, curr_list, DCC_FD_BASE);
> + dcc_list_writel(drvdata, 0, curr_list, DCC_LL_LOCK);
> + clear_bit(curr_list, drvdata->enable_bitmap);
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> +}
> +
> +static u32 dcc_filp_curr_list(const struct file *filp)
> +{
> + struct dentry *dentry = file_dentry(filp);
> + int curr_list, ret;
> +
> + ret = kstrtoint(dentry->d_parent->d_name.name, 0, &curr_list);
> + if (ret)
> + return ret;
> +
> + return curr_list;
> +}
> +
> +static ssize_t enable_read(struct file *filp, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + char *buf;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + if (is_dcc_enabled(drvdata))
> + buf = "Y\n";
> + else
> + buf = "N\n";
> +
> + mutex_unlock(&drvdata->mutex);
> +
> + return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
> +}
> +
> +static ssize_t enable_write(struct file *filp, const char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + int ret = 0, curr_list;
> + bool val;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + curr_list = dcc_filp_curr_list(filp);
> + if (curr_list < 0)
> + return curr_list;
> +
> + ret = kstrtobool_from_user(userbuf, count, &val);
> + if (ret < 0)
> + return ret;
> +
> + if (val) {
> + ret = dcc_enable(drvdata, curr_list);
> + if (ret)
> + return ret;
> + } else {
> + dcc_disable(drvdata, curr_list);
> + }
> +
> + return count;
> +}
> +
> +static const struct file_operations enable_fops = {
> + .read = enable_read,
> + .write = enable_write,
> + .open = simple_open,
> + .llseek = generic_file_llseek,
> +};
> +
> +static ssize_t trigger_write(struct file *filp,
> + const char __user *user_buf, size_t count,
> + loff_t *ppos)
> +{
> + int ret;
> + unsigned int val;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + ret = kstrtouint_from_user(user_buf, count, 0, &val);
> + if (ret < 0)
> + return ret;
> +
> + if (val != 1)
> + return -EINVAL;
> +
> + ret = dcc_sw_trigger(drvdata);
> + if (ret < 0)
> + return ret;
> +
> + return count;
> +}
> +
> +static const struct file_operations trigger_fops = {
> + .write = trigger_write,
> + .open = simple_open,
> + .llseek = generic_file_llseek,
> +};
> +
> +static int dcc_config_add(struct dcc_drvdata *drvdata, unsigned int addr,
> + unsigned int len, bool apb_bus, int curr_list)
> +{
> + int ret = 0;
> + struct dcc_config_entry *entry, *pentry;
> + unsigned int base, offset;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + if (!len || len > drvdata->ram_size / DCC_WORD_SIZE) {
> + dev_err(drvdata->dev, "DCC: Invalid length\n");
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> +
> + base = addr & DCC_ADDR_RANGE_MASK;
> +
> + if (!list_empty(&drvdata->cfg_head[curr_list])) {
> + pentry = list_last_entry(&drvdata->cfg_head[curr_list],
> + struct dcc_config_entry, list);
> +
> + if (pentry->desc_type == DCC_READ_TYPE &&
> + addr >= (pentry->base + pentry->offset) &&
> + addr <= (pentry->base + pentry->offset + MAX_DCC_OFFSET)) {
> + /* Re-use base address from last entry */
> + base = pentry->base;
> +
> + if ((pentry->len * 4 + pentry->base + pentry->offset)
> + == addr) {
> + len += pentry->len;
> +
> + if (len > MAX_DCC_LEN)
> + pentry->len = MAX_DCC_LEN;
> + else
> + pentry->len = len;
> +
> + addr = pentry->base + pentry->offset +
> + pentry->len * 4;
> + len -= pentry->len;
> + }
> + }
> + }
> +
> + offset = addr - base;
> +
> + while (len) {
> + entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + ret = -ENOMEM;
> + goto out_unlock;
> + }
> +
> + entry->base = base;
> + entry->offset = offset;
> + entry->len = min_t(u32, len, MAX_DCC_LEN);
> + entry->desc_type = DCC_READ_TYPE;
> + entry->apb_bus = apb_bus;
> + INIT_LIST_HEAD(&entry->list);
> + list_add_tail(&entry->list,
> + &drvdata->cfg_head[curr_list]);
> +
> + len -= entry->len;
> + offset += MAX_DCC_LEN * 4;
> + }
> +
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> + return ret;
> +}
> +
> +static ssize_t dcc_config_add_read(struct dcc_drvdata *drvdata, char *buf, int curr_list)
> +{
> + bool bus;
> + int len, nval;
> + unsigned int base;
> + char apb_bus[4];
> +
> + nval = sscanf(buf, "%x %i %3s", &base, &len, apb_bus);
> + if (nval <= 0 || nval > 3)
> + return -EINVAL;
> +
> + if (nval == 1) {
> + len = 1;
> + bus = false;
> + } else if (nval == 2) {
> + bus = false;
> + } else if (!strcmp("apb", apb_bus)) {
> + bus = true;
> + } else if (!strcmp("ahb", apb_bus)) {
> + bus = false;
> + } else {
> + return -EINVAL;
> + }
> +
> + return dcc_config_add(drvdata, base, len, bus, curr_list);
> +}
> +
> +static void dcc_config_reset(struct dcc_drvdata *drvdata)
> +{
> + struct dcc_config_entry *entry, *temp;
> + int curr_list;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + for (curr_list = 0; curr_list < drvdata->nr_link_list; curr_list++) {
> + list_for_each_entry_safe(entry, temp,
> + &drvdata->cfg_head[curr_list], list) {
> + list_del(&entry->list);
> + kfree(entry);
> + }
> + }
> + drvdata->ram_start = 0;
> + drvdata->ram_cfg = 0;
> + mutex_unlock(&drvdata->mutex);
> +}
> +
> +static ssize_t config_reset_write(struct file *filp,
> + const char __user *user_buf, size_t count,
> + loff_t *ppos)
> +{
> + unsigned int val, ret;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + ret = kstrtouint_from_user(user_buf, count, 0, &val);
> + if (ret < 0)
> + return ret;
> +
> + if (val)
> + dcc_config_reset(drvdata);
> +
> + return count;
> +}
> +
> +static const struct file_operations config_reset_fops = {
> + .write = config_reset_write,
> + .open = simple_open,
> + .llseek = generic_file_llseek,
> +};
> +
> +static ssize_t ready_read(struct file *filp, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + int ret = 0;
> + char *buf;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + if (!is_dcc_enabled(drvdata)) {
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> +
> + if (!FIELD_GET(BIT(1), readl(drvdata->base + dcc_status(drvdata->mem_map_ver))))
> + buf = "Y\n";
> + else
> + buf = "N\n";
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> +
> + if (ret < 0)
> + return -EINVAL;
> + else
You do the "lock, get a value, unlock, do something with the value"
thing a bunch, but what prevents the value from changing after the lock
happens? So why is the lock needed at all?
thanks,
greg k-h
> + return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf) + 1);
> +}
> +
> +static const struct file_operations ready_fops = {
> + .read = ready_read,
> + .open = simple_open,
> + .llseek = generic_file_llseek,
> +};
> +
> +static int dcc_add_loop(struct dcc_drvdata *drvdata, unsigned long loop_cnt, int curr_list)
> +{
> + struct dcc_config_entry *entry;
> +
> + entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry)
> + return -ENOMEM;
> +
> + entry->loop_cnt = min_t(u32, loop_cnt, MAX_LOOP_CNT);
> + entry->desc_type = DCC_LOOP_TYPE;
> + INIT_LIST_HEAD(&entry->list);
> + list_add_tail(&entry->list, &drvdata->cfg_head[curr_list]);
> +
> + return 0;
> +}
> +
> +static ssize_t dcc_config_add_loop(struct dcc_drvdata *drvdata, char *buf, int curr_list)
> +{
> + int ret, i = 0;
> + char *token, *input;
> + char delim[2] = " ";
> + unsigned int val[MAX_LOOP_ADDR];
> +
> + input = buf;
> +
> + while ((token = strsep(&input, delim)) && i < MAX_LOOP_ADDR) {
> + ret = kstrtoint(token, 0, &val[i++]);
> + if (ret)
> + return ret;
> + }
> +
> + if (token) {
> + dev_err(drvdata->dev, "Max limit %u of loop address exceeded",
> + MAX_LOOP_ADDR);
> + return -EINVAL;
> + }
> +
> + if (val[1] < 1 || val[1] > 8)
> + return -EINVAL;
> +
> + ret = dcc_add_loop(drvdata, val[0], curr_list);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < val[1]; i++)
> + dcc_config_add(drvdata, val[i + 2], 1, false, curr_list);
> +
> + return dcc_add_loop(drvdata, 1, curr_list);
> +}
> +
> +static int dcc_rd_mod_wr_add(struct dcc_drvdata *drvdata, unsigned int mask,
> + unsigned int val, int curr_list)
> +{
> + int ret = 0;
> + struct dcc_config_entry *entry;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + if (list_empty(&drvdata->cfg_head[curr_list])) {
> + dev_err(drvdata->dev, "DCC: No read address programmed\n");
> + ret = -EPERM;
> + goto out_unlock;
> + }
> +
> + entry = devm_kzalloc(drvdata->dev, sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + ret = -ENOMEM;
> + goto out_unlock;
> + }
> +
> + entry->desc_type = DCC_READ_WRITE_TYPE;
> + entry->mask = mask;
> + entry->write_val = val;
> + list_add_tail(&entry->list, &drvdata->cfg_head[curr_list]);
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> + return ret;
> +}
> +
> +static ssize_t dcc_config_add_read_write(struct dcc_drvdata *drvdata, char *buf, int curr_list)
> +{
> + int ret;
> + int nval;
> + unsigned int addr, mask, val;
> +
> + nval = sscanf(buf, "%x %x %x", &addr, &mask, &val);
> +
> + if (nval <= 1 || nval > 3)
> + return -EINVAL;
> +
> + ret = dcc_config_add(drvdata, addr, 1, false, curr_list);
> + if (ret)
> + return ret;
> +
> + return dcc_rd_mod_wr_add(drvdata, mask, val, curr_list);
> +}
> +
> +static int dcc_add_write(struct dcc_drvdata *drvdata, unsigned int addr,
> + unsigned int write_val, int apb_bus, int curr_list)
> +{
> + struct dcc_config_entry *entry;
> +
> + entry = devm_kzalloc(drvdata->dev, sizeof(*entry), GFP_KERNEL);
> + if (!entry)
> + return -ENOMEM;
> +
> + entry->desc_type = DCC_WRITE_TYPE;
> + entry->base = addr & GENMASK(31, 4);
> + entry->offset = addr - entry->base;
> + entry->write_val = write_val;
> + entry->len = 1;
> + entry->apb_bus = apb_bus;
> + list_add_tail(&entry->list, &drvdata->cfg_head[curr_list]);
> +
> + return 0;
> +}
> +
> +static ssize_t dcc_config_add_write(struct dcc_drvdata *drvdata, char *buf, int curr_list)
> +{
> + bool bus;
> + int nval;
> + unsigned int addr, write_val;
> + char apb_bus[4];
> +
> + nval = sscanf(buf, "%x %x %3s", &addr, &write_val, apb_bus);
> +
> + if (nval <= 1 || nval > 3)
> + return -EINVAL;
> +
> + if (nval == 2)
> + bus = true;
> +
> + if (nval == 3) {
> + if (!strcmp("apb", apb_bus))
> + bus = true;
> + else if (!strcmp("ahb", apb_bus))
> + bus = false;
> + else
> + return -EINVAL;
> + }
> +
> + return dcc_add_write(drvdata, addr, write_val, bus, curr_list);
> +}
> +
> +static int config_show(struct seq_file *m, void *data)
> +{
> + struct dcc_drvdata *drvdata = m->private;
> + struct dcc_config_entry *entry;
> + int index = 0, curr_list;
> +
> + curr_list = dcc_filp_curr_list(m->file);
> + if (curr_list < 0)
> + return curr_list;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + list_for_each_entry(entry, &drvdata->cfg_head[curr_list], list) {
> + index++;
> + switch (entry->desc_type) {
> + case DCC_READ_WRITE_TYPE:
> + seq_printf(m, "RW mask: 0x%x, val: 0x%x\n index: 0x%x\n",
> + entry->mask, entry->write_val, index);
> + break;
> + case DCC_LOOP_TYPE:
> + seq_printf(m, "L index: 0x%x Loop: %d\n", index, entry->loop_cnt);
> + break;
> + case DCC_WRITE_TYPE:
> + seq_printf(m, "W Base:0x%x, Offset: 0x%x, val: 0x%x, APB: %d\n, Index: 0x%x\n",
> + entry->base, entry->offset, entry->write_val, entry->apb_bus,
> + index);
> + break;
> + case DCC_READ_TYPE:
> + seq_printf(m, "R Base:0x%x, Offset: 0x%x, len: 0x%x, APB: %d\n, Index: 0x%x\n",
> + entry->base, entry->offset, entry->len, entry->apb_bus, index);
> + }
> + }
> + mutex_unlock(&drvdata->mutex);
> + return 0;
> +}
> +
> +static int config_open(struct inode *inode, struct file *file)
> +{
> + struct dcc_drvdata *drvdata = inode->i_private;
> +
> + return single_open(file, config_show, drvdata);
> +}
> +
> +static ssize_t config_write(struct file *filp,
> + const char __user *user_buf, size_t count,
> + loff_t *ppos)
> +{
> + int ret, curr_list;
> + char *token, buf[50];
> + char *bufp = buf;
> + char *delim = " ";
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + if (count > sizeof(buf) || count == 0)
> + return -EINVAL;
> +
> + ret = copy_from_user(buf, user_buf, count);
> + if (ret)
> + return -EFAULT;
> +
> + curr_list = dcc_filp_curr_list(filp);
> + if (curr_list < 0)
> + return curr_list;
> +
> + if (buf[count - 1] == '\n')
> + buf[count - 1] = '\0';
> + else
> + return -EINVAL;
> +
> + token = strsep(&bufp, delim);
> +
> + if (!strcmp("R", token)) {
> + ret = dcc_config_add_read(drvdata, bufp, curr_list);
> + } else if (!strcmp("W", token)) {
> + ret = dcc_config_add_write(drvdata, bufp, curr_list);
> + } else if (!strcmp("RW", token)) {
> + ret = dcc_config_add_read_write(drvdata, bufp, curr_list);
> + } else if (!strcmp("L", token)) {
> + ret = dcc_config_add_loop(drvdata, bufp, curr_list);
> + } else {
> + dev_err(drvdata->dev, "%s is not a correct input\n", token);
> + return -EINVAL;
> + }
> +
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static const struct file_operations config_fops = {
> + .open = config_open,
> + .read = seq_read,
> + .write = config_write,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
> +
> +static void dcc_delete_debug_dir(struct dcc_drvdata *drvdata)
> +{
> + debugfs_remove_recursive(drvdata->dbg_dir);
> +};
> +
> +static void dcc_create_debug_dir(struct dcc_drvdata *drvdata)
> +{
> + int i;
> + char list_num[10];
> + struct dentry *dcc_dev, *list;
> + struct device *dev = drvdata->dev;
> +
> + drvdata->dbg_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
> + dcc_dev = debugfs_create_dir(dev_name(dev), drvdata->dbg_dir);
> +
> + for (i = 0; i <= drvdata->nr_link_list; i++) {
> + sprintf(list_num, "%d", i);
> + list = debugfs_create_dir(list_num, dcc_dev);
> + debugfs_create_file("enable", 0600, list, drvdata, &enable_fops);
> + debugfs_create_file("config", 0600, list, drvdata, &config_fops);
> + }
> +
> + debugfs_create_file("trigger", 0200, drvdata->dbg_dir, drvdata, &trigger_fops);
> + debugfs_create_file("ready", 0400, drvdata->dbg_dir, drvdata, &ready_fops);
> + debugfs_create_file("config_reset", 0200, drvdata->dbg_dir,
> + drvdata, &config_reset_fops);
> +}
> +
> +static ssize_t dcc_sram_read(struct file *file, char __user *data,
> + size_t len, loff_t *ppos)
> +{
> + unsigned char *buf;
> + struct dcc_drvdata *drvdata;
> +
> + drvdata = container_of(file->private_data, struct dcc_drvdata,
> + sram_dev);
> +
> + /* EOF check */
> + if (*ppos >= drvdata->ram_size)
> + return 0;
> +
> + if ((*ppos + len) > drvdata->ram_size)
> + len = (drvdata->ram_size - *ppos);
> +
> + buf = kzalloc(len, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + memcpy_fromio(buf, drvdata->ram_base + *ppos, len);
> +
> + if (copy_to_user(data, buf, len)) {
> + kfree(buf);
> + return -EFAULT;
> + }
> +
> + *ppos += len;
> +
> + kfree(buf);
> +
> + return len;
> +}
> +
> +static const struct file_operations dcc_sram_fops = {
> + .owner = THIS_MODULE,
> + .read = dcc_sram_read,
> + .llseek = no_llseek,
> +};
> +
> +static int dcc_sram_dev_init(struct dcc_drvdata *drvdata)
> +{
> + drvdata->sram_dev.minor = MISC_DYNAMIC_MINOR;
> + drvdata->sram_dev.name = "dcc_sram";
> + drvdata->sram_dev.fops = &dcc_sram_fops;
> +
> + return misc_register(&drvdata->sram_dev);
> +}
> +
> +static void dcc_sram_dev_exit(struct dcc_drvdata *drvdata)
> +{
> + misc_deregister(&drvdata->sram_dev);
> +}
> +
> +static int dcc_probe(struct platform_device *pdev)
> +{
> + u32 val;
> + int ret = 0, i;
> + struct device *dev = &pdev->dev;
> + struct dcc_drvdata *drvdata;
> + struct resource *res;
> +
> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
> +
> + drvdata->dev = &pdev->dev;
> + platform_set_drvdata(pdev, drvdata);
> +
> + drvdata->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(drvdata->base))
> + return PTR_ERR(drvdata->base);
> +
> + drvdata->ram_base = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> + if (IS_ERR(drvdata->ram_base))
> + return PTR_ERR(drvdata->ram_base);
> +
> + drvdata->ram_size = resource_size(res);
> +
> + drvdata->ram_offset = (size_t)of_device_get_match_data(&pdev->dev);
> +
> + val = readl(drvdata->base + DCC_HW_INFO);
> +
> + if (FIELD_GET(DCC_VER_INFO_MASK, val)) {
> + drvdata->mem_map_ver = 3;
> + drvdata->nr_link_list = readl(drvdata->base + DCC_LL_NUM_INFO);
> + if (!drvdata->nr_link_list)
> + return -EINVAL;
> + } else if ((val & DCC_VER_MASK2) == DCC_VER_MASK2) {
> + drvdata->mem_map_ver = 2;
> + drvdata->nr_link_list = readl(drvdata->base + DCC_LL_NUM_INFO);
> + if (!drvdata->nr_link_list)
> + return -EINVAL;
> + } else {
> + drvdata->mem_map_ver = 1;
> + drvdata->nr_link_list = DCC_MAX_LINK_LIST;
> + }
> +
> + /* Either set the fixed loop offset or calculate
> + * it from the total number of words in dcc_sram.
> + * Max consecutive addresses dcc can loop is
> + * equivalent to the words in dcc_sram.
> + */
> + if (val & DCC_LOOP_OFFSET_MASK)
> + drvdata->loop_shift = DCC_FIX_LOOP_OFFSET;
> + else
> + drvdata->loop_shift = get_bitmask_order((drvdata->ram_offset +
> + drvdata->ram_size) / DCC_SRAM_WORD_LENGTH - 1);
> +
> + mutex_init(&drvdata->mutex);
> +
> + drvdata->enable_bitmap = devm_kcalloc(dev, BITS_TO_LONGS(drvdata->nr_link_list),
> + sizeof(*drvdata->enable_bitmap), GFP_KERNEL);
> + if (!drvdata->enable_bitmap)
> + return -ENOMEM;
> +
> + drvdata->cfg_head = devm_kcalloc(dev, drvdata->nr_link_list,
> + sizeof(*drvdata->cfg_head), GFP_KERNEL);
> + if (!drvdata->cfg_head)
> + return -ENOMEM;
> +
> + for (i = 0; i < drvdata->nr_link_list; i++)
> + INIT_LIST_HEAD(&drvdata->cfg_head[i]);
> +
> + ret = dcc_sram_dev_init(drvdata);
> + if (ret) {
> + dev_err(drvdata->dev, "DCC: sram node not registered.\n");
> + return ret;
> + }
> +
> + dcc_create_debug_dir(drvdata);
> +
> + return 0;
> +}
> +
> +static int dcc_remove(struct platform_device *pdev)
> +{
> + struct dcc_drvdata *drvdata = platform_get_drvdata(pdev);
> +
> + dcc_delete_debug_dir(drvdata);
> + dcc_sram_dev_exit(drvdata);
> + dcc_config_reset(drvdata);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id dcc_match_table[] = {
> + { .compatible = "qcom,sc7180-dcc", .data = (void *)0x6000 },
> + { .compatible = "qcom,sc7280-dcc", .data = (void *)0x12000 },
> + { .compatible = "qcom,sdm845-dcc", .data = (void *)0x6000 },
> + { .compatible = "qcom,sm8150-dcc", .data = (void *)0x5000 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, dcc_match_table);
> +
> +static struct platform_driver dcc_driver = {
> + .probe = dcc_probe,
> + .remove = dcc_remove,
> + .driver = {
> + .name = "qcom-dcc",
> + .of_match_table = dcc_match_table,
> + },
> +};
> +
> +module_platform_driver(dcc_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Qualcomm Technologies Inc. DCC driver");
> +
> --
> 2.17.1
>
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