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Date: Wed, 14 Sep 2022 22:33:57 -0500
From: Bjorn Andersson <andersson@...nel.org>
To: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
Cc: Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Rob Herring <robh+dt@...nel.org>, Alex Elder <elder@...e.org>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
Sai Prakash Ranjan <quic_saipraka@...cinc.com>,
Sibi Sankar <quic_sibis@...cinc.com>,
Rajendra Nayak <quic_rjendra@...cinc.com>, vkoul@...nel.org
Subject: Re: [PATCH V9 2/7] soc: qcom: dcc:Add driver support for Data
Capture and Compare unit(DCC)
On Wed, Sep 14, 2022 at 10:31:12PM +0530, Souradeep Chowdhury wrote:
> diff --git a/drivers/soc/qcom/dcc.c b/drivers/soc/qcom/dcc.c
[..]
> +static inline void dcc_ll_writel(struct dcc_drvdata *drvdata,
> + u32 ll, u32 val, u32 off)
> +{
> + u32 offset = DCC_LL_OFFSET(drvdata->mem_map_ver) + off;
> +
> + writel((val), drvdata->base + ll * 0x80 + offset);
Extra () around val.
> +}
> +
> +static inline u32 dcc_ll_readl(struct dcc_drvdata *drvdata, u32 ll, u32 off)
> +{
> + u32 offset = DCC_LL_OFFSET(drvdata->mem_map_ver) + off;
> +
> + return readl(drvdata->base + ll * 0x80 + offset);
> +}
> +
> +static void dcc_sram_write_auto(struct dcc_drvdata *drvdata,
> + u32 val, u32 *off)
> +{
> + writel(val, drvdata->ram_base + *off);
> +
> + *off += 4;
> +}
> +
> +static int dcc_read_and_clear(struct dcc_drvdata *drvdata)
> +{
> + int i;
> + u32 bus_status;
> + u32 ll_cfg;
> + u32 tmp_ll_cfg;
> +
> + for (i = 0; i < drvdata->nr_link_list; i++) {
> + if (!drvdata->enable[i])
> + continue;
> +
> + bus_status = dcc_ll_readl(drvdata, i, DCC_LL_BUS_ACCESS_STATUS);
> + if (!bus_status)
> + continue;
> +
> + dev_err(drvdata->dev,
> + "Read access error for list %d err: 0x%x.\n", i, bus_status);
> + ll_cfg = dcc_ll_readl(drvdata, i, DCC_LL_CFG);
> + tmp_ll_cfg = ll_cfg & ~DCC_TRIGGER_MASK;
> + dcc_ll_writel(drvdata, tmp_ll_cfg, i, DCC_LL_CFG);
> + dcc_ll_writel(drvdata, DCC_STATUS_MASK, i,
> + DCC_LL_BUS_ACCESS_STATUS);
> + dcc_ll_writel(drvdata, ll_cfg, i, DCC_LL_CFG);
> + return -ENODATA;
> + }
> +
> + return 0;
> +}
> +
> +static int dcc_sw_trigger(struct dcc_drvdata *drvdata)
> +{
> + void __iomem *addr;
> + int ret;
> + int i;
> + u32 ll_cfg;
> + u32 tmp_ll_cfg;
> + u32 val;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + for (i = 0; i < drvdata->nr_link_list; i++) {
> + if (!drvdata->enable[i])
> + continue;
> + ll_cfg = dcc_ll_readl(drvdata, i, DCC_LL_CFG);
> + tmp_ll_cfg = ll_cfg & ~DCC_TRIGGER_MASK;
> + dcc_ll_writel(drvdata, tmp_ll_cfg, i, DCC_LL_CFG);
> + dcc_ll_writel(drvdata, 1, i, DCC_LL_SW_TRIGGER);
> + dcc_ll_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) == 0),
> + 1, STATUS_READY_TIMEOUT)) {
Please align wrapped line with the open parenthesis.
> + dev_err(drvdata->dev,
> + "DCC is busy after receiving sw tigger.\n");
> + ret = -EBUSY;
> + goto out_unlock;
> + }
> +
> + ret = dcc_read_and_clear(drvdata);
> +
> +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)
> +{
> + /* 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) {
> + cfg_loop->loop = (cfg->sram_offset - cfg_loop->loop_off) / 4;
> + cfg_loop->loop |= (cfg_loop->loop_cnt << drvdata->loopoff) &
> + GENMASK(DCC_ADDR_LIMIT, drvdata->loopoff);
> + cfg_loop->loop |= DCC_LOOP_DESCRIPTOR;
> + *total_len += (*total_len - cfg_loop->loop_len) * cfg_loop->loop_cnt;
> +
> + dcc_sram_write_auto(drvdata, cfg_loop->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 *total_len)
> +{
> + 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 & GENMASK(7, 0)) | BIT(15) | ((entry->len << 8) & GENMASK(14, 8)));
> + 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)
> +{
> + int ret = 0;
> + 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);
> + ret = -EINVAL;
> + return ret;
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 ret;
ret is 0 here, so return 0.
> +}
> +
> +static int __dcc_emit_config(struct dcc_drvdata *drvdata, int curr_list)
> +{
> + int ret;
> + u32 total_len, pos;
> + struct dcc_config_entry *entry;
> + struct dcc_cfg_attr cfg;
> + struct dcc_cfg_loop_attr cfg_loop;
> +
> + memset(&cfg, 0, sizeof(cfg));
> + memset(&cfg_loop, 0, sizeof(cfg_loop));
> + 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, &total_len);
> + break;
> +
> + case DCC_READ_TYPE:
> + ret = _dcc_emit_read(drvdata, entry, &cfg, &pos, &total_len);
> + if (ret)
> + goto overstep;
> + 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 int dcc_valid_list(struct dcc_drvdata *drvdata, int curr_list)
> +{
> + u32 lock_reg;
> +
> + if (list_empty(&drvdata->cfg_head[curr_list]))
> + return -EINVAL;
> +
> + if (drvdata->enable[curr_list]) {
> + dev_err(drvdata->dev, "List %d is already enabled\n",
> + curr_list);
Write your code to look good in 80 chars, but you may use up to 100
chars if that looks better. So please unwrap lines like this.
> + return -EINVAL;
> + }
> +
> + lock_reg = dcc_ll_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 -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static bool is_dcc_enabled(struct dcc_drvdata *drvdata)
> +{
> + bool dcc_enable = false;
> + int list;
> +
> + for (list = 0; list < DCC_MAX_LINK_LIST; list++) {
> + if (drvdata->enable[list]) {
> + dcc_enable = true;
Just return true;
> + break;
> + }
> + }
> +
> + return dcc_enable;
return false;
And you can drop all the {}
> +}
> +
> +static int dcc_enable(struct dcc_drvdata *drvdata, int curr_list)
> +{
> + int ret;
> + u32 ram_cfg_base;
> +
> + mutex_lock(&drvdata->mutex);
> +
> + ret = dcc_valid_list(drvdata, curr_list);
> + if (ret)
> + 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);
This isn't even 80 chars, please unwrap.
> + }
> +
> + /* 1. Take ownership of the list */
> + dcc_ll_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_ll_writel(drvdata, 0, curr_list, DCC_LL_LOCK);
> + goto out_unlock;
> + }
> +
> + /* 3. Program DCC_RAM_CFG reg */
> + dcc_ll_writel(drvdata, ram_cfg_base +
> + drvdata->ram_offset/4, curr_list, DCC_LL_BASE);
> + dcc_ll_writel(drvdata, drvdata->ram_start +
> + drvdata->ram_offset/4, curr_list, DCC_FD_BASE);
> + dcc_ll_writel(drvdata, 0xFFF, curr_list, DCC_LL_TIMEOUT);
> +
> + /* 4. Clears interrupt status register */
> + dcc_ll_writel(drvdata, 0, curr_list, DCC_LL_INT_ENABLE);
> + dcc_ll_writel(drvdata, (BIT(0) | BIT(1) | BIT(2)),
> + curr_list, DCC_LL_INT_STATUS);
> +
> + drvdata->enable[curr_list] = true;
> +
> + /* 5. Configure trigger */
> + dcc_ll_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 (!drvdata->enable[curr_list])
> + goto out_unlock;
> + dcc_ll_writel(drvdata, 0, curr_list, DCC_LL_CFG);
> + dcc_ll_writel(drvdata, 0, curr_list, DCC_LL_BASE);
> + dcc_ll_writel(drvdata, 0, curr_list, DCC_FD_BASE);
> + dcc_ll_writel(drvdata, 0, curr_list, DCC_LL_LOCK);
> + drvdata->enable[curr_list] = false;
> +out_unlock:
> + mutex_unlock(&drvdata->mutex);
> +}
> +
> +static u32 dcc_filp_curr_list(struct file *filp)
> +{
> + struct dentry *dentry = file_dentry(filp);
> + int curr_list, ret;
> +
> + ret = kstrtoint(dentry->d_parent->d_name.name, 0, &curr_list);
ret is unused.
I do find the use of the d_name non-standard, wonder if there's a better
way?
> + return curr_list;
> +}
> +
> +static ssize_t enable_read(struct file *filp, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + int curr_list;
> + char *buf;
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + curr_list = dcc_filp_curr_list(filp);
curr_list is unused after assignment?
> +
> + 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) + 1);
> +}
> +
> +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);
> +
> + ret = kstrtobool_from_user(userbuf, count, &val);
> + if (ret < 0)
> + return ret;
> +
> + if (val)
> + ret = dcc_enable(drvdata, curr_list);
> + else
> + dcc_disable(drvdata, curr_list);
> +
> + if (!ret)
> + ret = count;
Rather than relying on ret being left unmodified in the !val case, I
would prefer that you check dcc_enable() for error and return ret there,
and then just return count at the end.
> +
> + return ret;
> +}
> +
> +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 = 0;
First access is assignment.
> + 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)
> + ret = count;
I would prefer
if (ret < 0)
return ret;
return count;
> +
> + return ret;
> +}
> +
> +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, int 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_ADDR_OFF_RANGE) {
> + dev_err(drvdata->dev, "DCC: Invalid length\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + 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 = devm_kzalloc(drvdata->dev, sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + 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;
> + }
> +
> +err:
Name it "out_unlock" instead, as it's not only the error path and that
make the unlock significant.
> + mutex_unlock(&drvdata->mutex);
> + return ret;
> +}
> +
> +static ssize_t dcc_config_add_read(struct dcc_drvdata *drvdata, char *buf, int curr_list)
> +{
> + int ret, len, nval, bus;
> + unsigned int base;
> + char apb_bus[4];
> +
> + nval = sscanf(buf, "%x %i %s", &base, &len, apb_bus);
> + if (nval <= 0 || nval > 3)
> + return -EINVAL;
> +
> + if (nval == 1) {
> + len = 1;
> + bus = 0;
> + } else if (nval == 2) {
> + bus = 0;
> + } else if (!strcmp("apb", apb_bus)) {
> + bus = 1;
> + } else if (!strcmp("ahb", apb_bus)) {
> + bus = 0;
> + } else {
> + return -EINVAL;
> + }
> +
> + ret = dcc_config_add(drvdata, base, len, bus, curr_list);
> + return ret;
No need for a local variable, just return dcc_config_add(...);
> +
> +}
> +
> +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);
> + devm_kfree(drvdata->dev, entry);
You do invoke dcc_config_reset() on remove() already, so skip the devm,
as you don't actually seem to use it.
> + }
> + }
> + 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 err;
> + }
> +
> + if (!FIELD_GET(BIT(1), readl(drvdata->base + DCC_STATUS(drvdata->mem_map_ver))))
> + buf = "Y\n";
> + else
> + buf = "N\n";
> +err:
out_unlock:
> + mutex_unlock(&drvdata->mutex);
> +
> + if (ret >= 0)
> + return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf) + 1);
> + else
> + return ret;
Although this might be cleaner with just a mutex_unlock(); return
-EINVAL; in the conditioanl above and then
return simple_read_from_buffer();
here.
If not it's idiomatic to handle the error case first.
> +}
> +
> +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 = devm_kzalloc(drvdata->dev, 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, cnt = 2, i = 0;
> + char *token, *input;
> + char delim[2] = " ";
> + unsigned int val[MAX_LOOP_ADDR];
> +
> + input = buf;
> +
> + token = strsep(&input, delim);
> + while (token != NULL) {
> + ret = kstrtoint(token, 0, &val[i++]);
> + if (ret)
> + return ret;
> +
> + token = strsep(&input, delim);
> + }
> +
> + 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[cnt++], 1, 0, curr_list);
> +
> + ret = dcc_add_loop(drvdata, 1, curr_list);
return dcc_add_loop();
> +
> + return ret;
> +}
> +
> +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 err;
> + }
> +
> + entry = devm_kzalloc(drvdata->dev, sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + entry->desc_type = DCC_READ_WRITE_TYPE;
> + entry->mask = mask;
> + entry->write_val = val;
> + INIT_LIST_HEAD(&entry->list);
> + list_add_tail(&entry->list, &drvdata->cfg_head[curr_list]);
> +err:
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, 0, curr_list);
> + if (ret)
> + return ret;
> +
> + ret = dcc_rd_mod_wr_add(drvdata, mask, val, curr_list);
> + return ret;
return dcc_rd_mod_wr_add()
> +
> +}
> +
> +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;
> + INIT_LIST_HEAD(&entry->list);
> + 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)
> +{
> + int ret, bus;
> + int nval;
> + unsigned int addr, write_val;
> + char apb_bus[4];
> +
> + nval = sscanf(buf, "%x %x %s", &addr, &write_val, apb_bus);
> +
> + if (nval <= 1 || nval > 3)
> + return -EINVAL;
> +
> + if (nval == 3) {
> + if (!strcmp("apb", apb_bus))
> + bus = 1;
> + else if (!strcmp("apb", apb_bus))
> + bus = 0;
> + else
> + return -EINVAL;
> + }
> +
> + ret = dcc_add_write(drvdata, addr, write_val, bus, curr_list);
> +
> + return ret;
> +}
> +
> +static ssize_t config_read(struct file *filp, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct dcc_drvdata *drvdata = filp->private_data;
> + struct dcc_config_entry *entry;
> + char local_buf[64], buf[100] = "\0";
> + int len = 0, tot_len = 0, index = 0, curr_list;
> +
> + mutex_lock(&drvdata->mutex);
> + curr_list = dcc_filp_curr_list(filp);
> +
> + list_for_each_entry(entry,
> + &drvdata->cfg_head[curr_list], list) {
> + index++;
> + switch (entry->desc_type) {
> + case DCC_READ_WRITE_TYPE:
> + len = snprintf(local_buf, 64,
> + "Index: 0x%x, mask: 0x%x, val: 0x%x\n",
> + index, entry->mask, entry->write_val);
> + break;
> + case DCC_LOOP_TYPE:
> + len = snprintf(local_buf, 64, "Index: 0x%x, Loop: %d\n",
> + index, entry->loop_cnt);
> + break;
> + case DCC_WRITE_TYPE:
> + len = snprintf(local_buf, 64,
> + "Write Index: 0x%x, Base: 0x%x, Offset: 0x%x, len: 0x%x APB: %d\n",
> + index, entry->base, entry->offset, entry->len,
> + entry->apb_bus);
> + break;
> + case DCC_READ_TYPE:
> + len = snprintf(local_buf, 64,
> + "Read Index: 0x%x, Base: 0x%x, Offset: 0x%x, len: 0x%x APB: %d\n",
> + index, entry->base, entry->offset,
> + entry->len, entry->apb_bus);
> + }
> + tot_len += len;
> + strlcat(buf, local_buf, sizeof(local_buf));
> + }
> + mutex_unlock(&drvdata->mutex);
> + return simple_read_from_buffer(userbuf, count, ppos, buf, tot_len);
> +}
> +
> +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 *delim = " ";
> + struct dcc_drvdata *drvdata = filp->private_data;
> +
> + ret = copy_from_user(buf, user_buf, count);
> + if (ret)
> + return -EFAULT;
> +
> + curr_list = dcc_filp_curr_list(filp);
> +
> + if (buf[count - 1] == '\n')
> + buf[count - 1] = '\0';
> +
> + token = strsep((char **)&buf, delim);
> +
> + if (!strcmp("R", token))
> + ret = dcc_config_add_read(drvdata, buf, curr_list);
> + else if (!strcmp("W", token))
> + ret = dcc_config_add_write(drvdata, buf, curr_list);
> + else if (!strcmp("RW", token))
> + ret = dcc_config_add_read_write(drvdata, buf, curr_list);
> + else if (!strcmp("L", token))
> + ret = dcc_config_add_loop(drvdata, buf, 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 = {
> + .read = config_read,
> + .write = config_write,
> + .open = simple_open,
> + .llseek = generic_file_llseek,
> +};
> +
> +void dcc_delete_debug_dir(struct dcc_drvdata *dcc)
> +{
> + debugfs_remove_recursive(dcc->dbg_dir);
> +};
> +
> +int dcc_create_debug_dir(struct dcc_drvdata *dcc)
> +{
> + int i;
> + char list_num[10];
> + struct dentry *list;
> + struct device *dev = dcc->dev;
> +
> + if (debugfs_initialized()) {
I'm not able to see the purpose of this check, you should be able to
just start calling the debugfs_create functions and let them fail if
this is the case.
> + dcc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
> + if (!dcc_dbg) {
> + pr_err("can't create debugfs dir\n");
> + return -1;
> + }
> + }
But in particular, if !debugfs_initialized() you will continue and do
this part, why?
> +
> + dcc->dbg_dir = debugfs_create_dir(dev_name(dev), dcc_dbg);
> + if (!dcc->dbg_dir)
> + return -1;
> + for (i = 0; i <= dcc->nr_link_list; i++) {
> + sprintf(list_num, "%d", i);
> + list = debugfs_create_dir(list_num, dcc->dbg_dir);
> + debugfs_create_file("enable", 0600, list, dcc, &enable_fops);
> + debugfs_create_file("config", 0600, list, dcc, &config_fops);
> + }
> +
> + debugfs_create_file("trigger", 0200, dcc->dbg_dir, dcc, &trigger_fops);
> + debugfs_create_file("ready", 0400, dcc->dbg_dir, dcc, &ready_fops);
> + debugfs_create_file("config_reset", 0200, dcc->dbg_dir,
> + dcc, &config_reset_fops);
> + return 0;
> +
> +}
> +
> +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 = container_of(file->private_data,
> + struct dcc_drvdata,
> + sram_dev);
> +
> + /* EOF check */
> + if (drvdata->ram_size <= *ppos)
ppos is the variable and ram_size is the "constant" you're checking
against. So I would prefer:
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)
> +{
> + int ret;
> +
> + drvdata->sram_dev.minor = MISC_DYNAMIC_MINOR;
> + drvdata->sram_dev.name = DCC_SRAM_NODE;
> + drvdata->sram_dev.fops = &dcc_sram_fops;
> +
> + ret = misc_register(&drvdata->sram_dev);
> + return ret;
return misc_register();
> +}
> +
> +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, size;
> + struct device *dev = &pdev->dev;
> + struct dcc_drvdata *dcc;
> + struct resource *res;
> +
> + dcc = devm_kzalloc(dev, sizeof(*dcc), GFP_KERNEL);
> + if (!dcc)
> + return -ENOMEM;
> +
> + dcc->dev = &pdev->dev;
> + platform_set_drvdata(pdev, dcc);
> +
> + dcc->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(dcc->base))
> + return PTR_ERR(dcc->base);
> +
> + dcc->ram_base = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> + if (IS_ERR(dcc->ram_base))
> + return PTR_ERR(dcc->ram_base);
> +
> + dcc->ram_size = resource_size(res);
> +
> + dcc->ram_offset = (size_t) of_device_get_match_data(&pdev->dev);
> +
> + val = dcc_readl(dcc, DCC_HW_INFO);
> +
> + if (FIELD_GET(DCC_VER_INFO_MASK, val)) {
> + dcc->mem_map_ver = 3;
> + dcc->nr_link_list = dcc_readl(dcc, DCC_LL_NUM_INFO);
> + if (dcc->nr_link_list == 0)
> + return -EINVAL;
> + } else if ((val & DCC_VER_MASK2) == DCC_VER_MASK2) {
> + dcc->mem_map_ver = 2;
> + dcc->nr_link_list = dcc_readl(dcc, DCC_LL_NUM_INFO);
> + if (dcc->nr_link_list == 0)
> + return -EINVAL;
> + } else {
> + dcc->mem_map_ver = 1;
> + dcc->nr_link_list = DCC_MAX_LINK_LIST;
> + }
> +
> + /* Either set the fixed loop offset or calculate it
> + * from ram_size.Max consecutive addresses the
> + * dcc can loop is equivalent to the ram size
> + */
> + if (val & DCC_LOOP_OFFSET_MASK)
> + dcc->loopoff = DCC_FIX_LOOP_OFFSET;
> + else
> + dcc->loopoff = get_bitmask_order((dcc->ram_size +
> + dcc->ram_offset) / 4 - 1);
> +
> + mutex_init(&dcc->mutex);
> + /* Allocate space for all entries at once */
> + size = sizeof(*dcc->enable) + sizeof(*dcc->cfg_head);
> +
> + dcc->enable = devm_kzalloc(dev, dcc->nr_link_list * size, GFP_KERNEL);
Use devm_kcalloc() when allocating an array of things.
> + if (!dcc->enable)
> + return -ENOMEM;
> +
> + dcc->cfg_head = (struct list_head *)(dcc->enable + dcc->nr_link_list);
> +
> + for (i = 0; i < dcc->nr_link_list; i++)
> + INIT_LIST_HEAD(&dcc->cfg_head[i]);
> +
> + ret = dcc_sram_dev_init(dcc);
> + if (ret) {
> + dev_err(dcc->dev, "DCC: sram node not registered.\n");
> + return ret;
> + }
> +
> + ret = dcc_create_debug_dir(dcc);
> + if (ret) {
> + dev_err(dcc->dev, "DCC: debugfs files not created.\n");
You need dcc_sram_dev_exit() here as well.
> + return ret;
> + }
> +
> + 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,sm8150-dcc", .data = (void *)0x5000 },
> + { .compatible = "qcom,sc7280-dcc", .data = (void *)0x12000 },
> + { .compatible = "qcom,sc7180-dcc", .data = (void *)0x6000 },
> + { .compatible = "qcom,sdm845-dcc", .data = (void *)0x6000 },
> + { }
> +};
> +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 v2");
Please make this just "GPL".
Overall, please run checkpatch.pl --strict on the patches.
Thanks,
Bjorn
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