[V10,2/7] soc: qcom: dcc:Add driver support for Data Capture and Compare unit(DCC)

diff --git a/Documentation/ABI/testing/debugfs-driver-dcc b/Documentation/ABI/testing/debugfs-driver-dcc
new file mode 100644
index 0000000..387f67e
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-driver-dcc
@@ -0,0 +1,98 @@ 
+What:           /sys/kernel/debug/dcc/.../ready
+Date:           September 2022
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This file is used to check the status of the dcc
+		hardware if it's ready to take the inputs. A 'Y'
+		here indicates dcc is in a ready condition.
+		Example:
+		cat /sys/kernel/debug/dcc/.../ready
+
+What:           /sys/kernel/debug/dcc/.../trigger
+Date:           September 2022
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This is the debugfs interface for manual software
+		triggers. The user can simply enter a 1 against
+		the debugfs file and enable a manual trigger.
+		Example:
+		echo  1 > /sys/kernel/debug/dcc/.../trigger
+
+What:           /sys/kernel/debug/dcc/.../config_reset
+Date:           September 2022
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This file is used to reset the configuration of
+		a dcc driver to the default configuration. This
+		means that all the previous addresses stored in
+		the driver gets removed and user needs to enter
+		the address values from the start.
+		Example:
+		echo  1 > /sys/kernel/debug/dcc/../config_reset
+
+What:           /sys/kernel/debug/dcc/.../[list-number]/config
+Date:           September 2022
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This stores the addresses of the registers which
+		should be read in case of a hardware crash or
+		manual software triggers. The addresses entered here
+		are considered under all the 4 types of dcc
+		instructions Read type, Write type, Read Modify Write
+		type and Loop type. The lists need to be configured
+		sequentially and not in a overlapping manner. As an
+		example user can jump to list x only after list y is
+		configured and enabled. The format for entering all
+		types of instructions are explained in examples as
+		follows.
+		Example:
+	         i)Read Type Instruction
+		   echo R <1> <2> <3> >/sys/kernel/debug/dcc/../[list-number]/config
+		   1->Address to be considered for reading the value.
+		   2->The word count of the addresses, read n words
+		      starting from address <1>. Each word is of 32 bits.
+		      If not entered 1 is considered.
+		   3->Can be 'apb' or 'ahb' which indicates if it is apb or ahb
+		      bus respectively. If not entered ahb is considered.
+		ii)Write Type Instruction
+		   echo W <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
+		   1->Address to be considered for writing the value.
+		   2->The value that needs to be written at the location.
+		   3->Can be a 'apb' or 'ahb' which indicates if it is apb or ahb
+		      but respectively.
+	       iii)Read Modify Write type instruction
+		   echo RW <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
+		   1->The address which needs to be considered for read then write.
+		   2->The value that needs to be written on the address.
+		   3->The mask of the value to be written.
+		iv)Loop Type Instruction
+		   echo L <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
+		   1->The loop count, the number of times the value of the addresses will be
+		      captured.
+		   2->The address count, total number of addresses to be entered in this
+		      instruction.
+		   3->The series of addresses to be entered separated by a space like <addr1>
+		      <addr2>... and so on.
+
+What:           /sys/kernel/debug/dcc/.../[list-number]/enable
+Date:           September 2022
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This debugfs interface is used for enabling the
+		the dcc hardware. Enable file is kept under the
+		directory list number for which the user wants
+		to enable it. For example if the user wants to
+		enable list 1, then he should go for
+		echo 1 > /sys/kernel/debug/dcc/.../1/enable.
+		On enabling the dcc, all the addresses entered
+		by the user for the corresponding list is written
+		into dcc sram which is read by the dcc hardware
+		on manual or crash induced triggers. Lists should
+		be enabled sequentially.For example after configuring
+		addresses for list 1 and enabling it, a user can
+		proceed to enable list 2 or vice versa.
+		Example:
+		echo  0 > /sys/kernel/debug/dcc/.../[list-number]/enable
+		(disable dcc for the corresponding list number)
+		echo  1 > /sys/kernel/debug/dcc/.../[list-number]/enable
+		(enable dcc for the corresponding list number)
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 79b568f..5101912 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -69,6 +69,14 @@  config QCOM_LLCC
 	  SDM845. This provides interfaces to clients that use the LLCC.
 	  Say yes here to enable LLCC slice driver.
 
+config QCOM_DCC
+	tristate "Qualcomm Technologies, Inc. Data Capture and Compare(DCC) engine driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	help
+	  This option enables driver for Data Capture and Compare engine. DCC
+	  driver provides interface to configure DCC block and read back
+	  captured data from DCC's internal SRAM.
+
 config QCOM_KRYO_L2_ACCESSORS
 	bool
 	depends on ARCH_QCOM && ARM64 || COMPILE_TEST
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index ad675a6..0aaf82b 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -4,6 +4,7 @@  obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
 obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
 obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
 obj-$(CONFIG_QCOM_CPR)		+= cpr.o
+obj-$(CONFIG_QCOM_DCC) += dcc.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
diff --git a/drivers/soc/qcom/dcc.c b/drivers/soc/qcom/dcc.c
new file mode 100644
index 0000000..c3b46c5
--- /dev/null
+++ b/drivers/soc/qcom/dcc.c
@@ -0,0 +1,1343 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copneight (c) 2015-2021, The Linex Fnendation. All rights reserved.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#define STATUS_READY_TIMEOUT		5000  /*microseconds*/
+
+#define DCC_SRAM_NODE "dcc_sram"
+
+/* DCC registers */
+#define DCC_HW_INFO			0x04
+#define DCC_LL_NUM_INFO			0x10
+#define DCC_STATUS(vers)		((vers) == 1 ? 0x0c : 0x1c)
+#define DCC_LL_OFFSET(vers) \
+	((vers) == 1 ? 0x1c : ((vers) == 2 ? 0x2c : 0x34))
+#define DCC_LL_LOCK			0x00
+#define DCC_LL_CFG			0x04
+#define DCC_LL_BASE			0x08
+#define DCC_FD_BASE			0x0c
+#define DCC_LL_TIMEOUT			0x10
+#define DCC_LL_INT_ENABLE		0x18
+#define DCC_LL_INT_STATUS		0x1c
+#define DCC_LL_SW_TRIGGER		0x2c
+#define DCC_LL_BUS_ACCESS_STATUS	0x30
+
+#define DCC_MAP_LEVEL1			0x18
+#define DCC_MAP_LEVEL2			0x34
+#define DCC_MAP_LEVEL3			0x4C
+
+#define DCC_MAP_OFFSET1			0x10
+#define DCC_MAP_OFFSET2			0x18
+#define DCC_MAP_OFFSET3			0x1C
+#define DCC_MAP_OFFSET4			0x8
+
+/*Default value used if a bit 6 in the HW_INFO register is set.*/
+#define DCC_FIX_LOOP_OFFSET		16
+
+/*Mask to find version info from HW_Info register*/
+#define DCC_VER_INFO_MASK		BIT(9)
+
+#define DCC_READ			0
+#define DCC_WRITE			1
+#define DCC_LOOP			2
+#define DCC_READ_WRITE			3
+
+#define MAX_DCC_OFFSET			GENMASK(9, 2)
+#define MAX_DCC_LEN			GENMASK(6, 0)
+#define MAX_LOOP_CNT			GENMASK(7, 0)
+#define MAX_LOOP_ADDR			10
+
+#define DCC_ADDR_DESCRIPTOR		0x00
+#define DCC_ADDR_LIMIT			27
+#define DCC_ADDR_OFF_RANGE		8
+#define DCC_ADDR_RANGE_MASK		GENMASK(31, 4)
+#define DCC_LOOP_DESCRIPTOR		BIT(30)
+#define DCC_RD_MOD_WR_DESCRIPTOR	BIT(31)
+#define DCC_LINK_DESCRIPTOR		GENMASK(31, 30)
+#define DCC_STATUS_MASK			GENMASK(1, 0)
+#define DCC_LOCK_MASK                   BIT(0)
+#define DCC_LOOP_OFFSET_MASK		BIT(6)
+#define DCC_TRIGGER_MASK		BIT(9)
+
+#define DCC_READ_IND			0x00
+#define DCC_WRITE_IND			(BIT(28))
+
+#define DCC_AHB_IND			0x00
+#define DCC_APB_IND			BIT(29)
+
+#define DCC_MAX_LINK_LIST		8
+#define DCC_INVALID_LINK_LIST		GENMASK(7, 0)
+
+#define DCC_VER_MASK1			GENMASK(6, 0)
+#define DCC_VER_MASK2			GENMASK(5, 0)
+
+#define DCC_RD_MOD_WR_ADDR              0xC105E
+
+/*DCC debugfs directory*/
+static struct dentry	*dcc_dbg;
+
+enum dcc_descriptor_type {
+	DCC_READ_TYPE,
+	DCC_LOOP_TYPE,
+	DCC_READ_WRITE_TYPE,
+	DCC_WRITE_TYPE
+};
+
+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_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:	      Micellaneous 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
+ * @loopoff:          Loop offset bits range for the addresses
+ * @enable:           This contains an array of linkedlist enable flags
+ */
+struct dcc_drvdata {
+	void __iomem		*base;
+	struct device		*dev;
+	struct mutex		mutex;
+	void __iomem		*ram_base;
+	size_t			ram_size;
+	size_t			ram_offset;
+	int			mem_map_ver;
+	phys_addr_t		ram_cfg;
+	phys_addr_t		ram_start;
+	struct miscdevice	sram_dev;
+	struct list_head	*cfg_head;
+	struct dentry		*dbg_dir;
+	size_t			nr_link_list;
+	u8			loopoff;
+	bool                    *enable;
+};
+
+struct dcc_cfg_attr {
+	u32	addr;
+	u32	prev_addr;
+	u32	prev_off;
+	u32	link;
+	u32	sram_offset;
+};
+
+struct dcc_cfg_loop_attr {
+	u32	loop;
+	u32	loop_cnt;
+	u32	loop_len;
+	u32	loop_off;
+	bool    loop_start;
+};
+
+static size_t dcc_offset_conv(struct dcc_drvdata *drvdata, size_t off)
+{
+	/* If the memory map version is 1, adjust the offset based on
+	 * the dcc version mask. If the memory map version is 2
+	 * adjust the offset if the dcc version mask is greater than
+	 * map level 2.For other conditions, just return the offset.
+	 */
+	if (drvdata->mem_map_ver == 1) {
+		if (FIELD_GET(DCC_VER_MASK1, off) >= DCC_MAP_LEVEL3)
+			return off - DCC_MAP_OFFSET3;
+		if (FIELD_GET(DCC_VER_MASK1, off) >= DCC_MAP_LEVEL2)
+			return off - DCC_MAP_OFFSET2;
+		else if (FIELD_GET(DCC_VER_MASK1, off) >= DCC_MAP_LEVEL1)
+			return off - DCC_MAP_OFFSET1;
+	} else if (drvdata->mem_map_ver == 2) {
+		if (FIELD_GET(DCC_VER_MASK1, off) >= DCC_MAP_LEVEL2)
+			return off - DCC_MAP_OFFSET4;
+	}
+
+	return off;
+}
+
+static inline u32 dcc_readl(struct dcc_drvdata *drvdata, u32 off)
+{
+	return readl(drvdata->base + dcc_offset_conv(drvdata, off));
+}
+
+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);
+}
+
+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)) {
+		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)
+{
+	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, 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);
+		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)
+{
+	int list;
+
+	for (list = 0; list < DCC_MAX_LINK_LIST; list++)
+		if (drvdata->enable[list])
+			return true;
+
+	return false;
+}
+
+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);
+
+	/* 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);
+	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) + 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);
+	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, 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 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 = devm_kzalloc(drvdata->dev, 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)
+{
+	int 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;
+	}
+
+	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);
+		}
+	}
+	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
+		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 = 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);
+
+	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;
+	INIT_LIST_HEAD(&entry->list);
+	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, 0, 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;
+	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);
+	if (curr_list < 0)
+		return curr_list;
+
+	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 (curr_list < 0)
+		return curr_list;
+
+	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;
+
+	dcc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
+	if (!dcc_dbg) {
+		pr_err("can't create debugfs dir\n");
+		return -1;
+	}
+
+	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 (*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_NODE;
+	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, 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_kcalloc(dev, dcc->nr_link_list, size, GFP_KERNEL);
+	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");
+		dcc_sram_dev_exit(dcc);
+		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");
+MODULE_DESCRIPTION("Qualcomm Technologies Inc. DCC driver");
+