Subject: [PATCH v3 2/2] memory: brcmstb: Add driver for DPFE

From: [email-masked] (Markus Mayer)
Date: Thu, 24 Aug 2017 16:36:26 -0700

From: Markus Mayer <[email-masked]>

This driver allows access to DRAM properties, such as the refresh rate,
via the Broadcom STB DDR PHY Front End (DPFE). The refresh rate can be
used as indirect indicator of the DRAM temperature.

The driver also allows setting of the sampling interval.

Signed-off-by: Markus Mayer <[email-masked]>
---
 MAINTAINERS                   |   8 +
 drivers/memory/Makefile       |   1 +
 drivers/memory/brcmstb_dpfe.c | 701 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 710 insertions(+)
 create mode 100644 drivers/memory/brcmstb_dpfe.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 205d397..dcafdca 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2935,6 +2935,14 @@ S:	Maintained
 F:	drivers/bcma/
 F:	include/linux/bcma/
 
+BROADCOM STB DPFE DRIVER
+M:	Markus Mayer <[email-masked]>
+M:	bcm-kernel-feedback-list at broadcom.com
+L:	linux-arm-kernel at lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+F:	Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.txt
+F:	drivers/memory/brcmstb_dpfe.c
+
 BROADCOM SYSTEMPORT ETHERNET DRIVER
 M:	Florian Fainelli <[email-masked]>
 L:	netdev at vger.kernel.org
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index e88097fb..9cb8b61 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -8,6 +8,7 @@ endif
 obj-$(CONFIG_ARM_PL172_MPMC)	+= pl172.o
 obj-$(CONFIG_ATMEL_SDRAMC)	+= atmel-sdramc.o
 obj-$(CONFIG_ATMEL_EBI)		+= atmel-ebi.o
+obj-$(CONFIG_ARCH_BRCMSTB)	+= brcmstb_dpfe.o
 obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
 obj-$(CONFIG_TI_EMIF)		+= emif.o
 obj-$(CONFIG_OMAP_GPMC)		+= omap-gpmc.o
diff --git a/drivers/memory/brcmstb_dpfe.c b/drivers/memory/brcmstb_dpfe.c
new file mode 100644
index 0000000..21242c4
--- /dev/null
+++ b/drivers/memory/brcmstb_dpfe.c
@@ -0,0 +1,701 @@
+/*
+ * DDR PHY Front End (DPFE) driver for Broadcom set top box SoCs
+ *
+ * Copyright (c) 2017 Broadcom
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+/*
+ * This driver provides access to the DPFE interface of Broadcom STB SoCs.
+ * The firmware running on the DCPU inside the DDR PHY can provide current
+ * information about the system's RAM, for instance the DRAM refresh rate.
+ * This can be used as an indirect indicator for the DRAM's temperature.
+ * Slower refresh rate means cooler RAM, higher refresh rate means hotter
+ * RAM.
+ *
+ * Throughout the driver, we use readl_relaxed() and writel_relaxed(), which
+ * already contain the appropriate le32_to_cpu()/cpu_to_le32() calls.
+ *
+ * Note regarding the loading of the firmware image: we use be32_to_cpu()
+ * and le_32_to_cpu(), so we can support the following four cases:
+ *     - LE kernel + LE firmware image (the most common case)
+ *     - LE kernel + BE firmware image
+ *     - BE kernel + LE firmware image
+ *     - BE kernel + BE firmware image
+ *
+ * The DPCU always runs in big endian mode. The firwmare image, however, can
+ * be in either format. Also, communication between host CPU and DCPU is
+ * always in little endian.
+ */
+
+#include <linux/delay.h>
+#include <linux/firmware.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+#define DRVNAME			"brcmstb-dpfe"
+#define FIRMWARE_NAME		"dpfe.bin"
+
+/* DCPU register offsets */
+#define REG_DCPU_RESET		0x0
+#define REG_TO_DCPU_MBOX	0x10
+#define REG_TO_HOST_MBOX	0x14
+
+/* Message RAM */
+#define DCPU_MSG_RAM(x)		(0x100 + (x) * sizeof(u32))
+
+/* DRAM Info Offsets & Masks */
+#define DRAM_INFO_INTERVAL	0x0
+#define DRAM_INFO_MR4		0x4
+#define DRAM_INFO_ERROR		0x8
+#define DRAM_INFO_MR4_MASK	0xff
+
+/* DRAM MR4 Offsets & Masks */
+#define DRAM_MR4_REFRESH	0x0	/* Refresh rate */
+#define DRAM_MR4_SR_ABORT	0x3	/* Self Refresh Abort */
+#define DRAM_MR4_PPRE		0x4	/* Post-package repair entry/exit */
+#define DRAM_MR4_TH_OFFS	0x5	/* Thermal Offset; vendor specific */
+#define DRAM_MR4_TUF		0x7	/* Temperature Update Flag */
+
+#define DRAM_MR4_REFRESH_MASK	0x7
+#define DRAM_MR4_SR_ABORT_MASK	0x1
+#define DRAM_MR4_PPRE_MASK	0x1
+#define DRAM_MR4_TH_OFFS_MASK	0x3
+#define DRAM_MR4_TUF_MASK	0x1
+
+/* DRAM Vendor Offsets & Masks */
+#define DRAM_VENDOR_MR5		0x0
+#define DRAM_VENDOR_MR6		0x4
+#define DRAM_VENDOR_MR7		0x8
+#define DRAM_VENDOR_MR8		0xc
+#define DRAM_VENDOR_ERROR	0x10
+#define DRAM_VENDOR_MASK	0xff
+
+/* Reset register bits & masks */
+#define DCPU_RESET_SHIFT	0x0
+#define DCPU_RESET_MASK		0x1
+#define DCPU_CLK_DISABLE_SHIFT	0x2
+
+/* DCPU return codes */
+#define DCPU_RET_ERROR_BIT	BIT(31)
+#define DCPU_RET_SUCCESS	0x1
+#define DCPU_RET_ERR_HEADER	(DCPU_RET_ERROR_BIT | BIT(0))
+#define DCPU_RET_ERR_INVAL	(DCPU_RET_ERROR_BIT | BIT(1))
+#define DCPU_RET_ERR_CHKSUM	(DCPU_RET_ERROR_BIT | BIT(2))
+#define DCPU_RET_ERR_COMMAND	(DCPU_RET_ERROR_BIT | BIT(3))
+/* This error code is not firmware defined and only used in the driver. */
+#define DCPU_RET_ERR_TIMEDOUT	(DCPU_RET_ERROR_BIT | BIT(4))
+
+/* Firmware magic */
+#define DPFE_BE_MAGIC		0xfe1010fe
+#define DPFE_LE_MAGIC		0xfe0101fe
+
+/* Error codes */
+#define ERR_INVALID_MAGIC	-1
+#define ERR_INVALID_SIZE	-2
+#define ERR_INVALID_CHKSUM	-3
+
+/* Message types */
+#define DPFE_MSG_TYPE_COMMAND	1
+#define DPFE_MSG_TYPE_RESPONSE	2
+
+#define DELAY_LOOP_MAX		200000
+
+enum dpfe_msg_fields {
+	MSG_HEADER,
+	MSG_COMMAND,
+	MSG_ARG_COUNT,
+	MSG_ARG0,
+	MSG_CHKSUM,
+	MSG_FIELD_MAX /* Last entry */
+};
+
+enum dpfe_commands {
+	DPFE_CMD_GET_INFO,
+	DPFE_CMD_GET_REFRESH,
+	DPFE_CMD_GET_VENDOR,
+	DPFE_CMD_MAX /* Last entry */
+};
+
+struct dpfe_msg {
+	u32 header;
+	u32 command;
+	u32 arg_count;
+	u32 arg0;
+	u32 chksum; /* This is the sum of all other entries. */
+};
+
+/*
+ * Format of the binary firmware file:
+ *
+ *   entry
+ *      0    header
+ *              value:  0xfe0101fe  <== little endian
+ *                      0xfe1010fe  <== big endian
+ *      1    sequence:
+ *              [31:16] total segments on this build
+ *              [15:0]  this segment sequence.
+ *      2    FW version
+ *      3    IMEM byte size
+ *      4    DMEM byte size
+ *           IMEM
+ *           DMEM
+ *      last checksum ==> sum of everything
+ */
+struct dpfe_firmware_header {
+	u32 magic;
+	u32 sequence;
+	u32 version;
+	u32 imem_size;
+	u32 dmem_size;
+};
+
+/* Things we only need during initialization. */
+struct init_data {
+	unsigned int dmem_len;
+	unsigned int imem_len;
+	unsigned int chksum;
+	bool is_big_endian;
+};
+
+/* Things we need for as long as we are active. */
+struct private_data {
+	void __iomem *regs;
+	void __iomem *dmem;
+	void __iomem *imem;
+	struct device *dev;
+	unsigned int index;
+	struct mutex lock;
+};
+
+static const char *error_text[] = {
+	"Success", "Header code incorrect", "Unknown command or argument",
+	"Incorrect checksum", "Malformed command", "Timed out",
+};
+
+/* List of supported firmware commands */
+static const u32 dpfe_commands[DPFE_CMD_MAX][MSG_FIELD_MAX] = {
+	[DPFE_CMD_GET_INFO] = {
+		[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+		[MSG_COMMAND] = 1,
+		[MSG_ARG_COUNT] = 1,
+		[MSG_ARG0] = 1,
+		[MSG_CHKSUM] = 4,
+	},
+	[DPFE_CMD_GET_REFRESH] = {
+		[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+		[MSG_COMMAND] = 2,
+		[MSG_ARG_COUNT] = 1,
+		[MSG_ARG0] = 1,
+		[MSG_CHKSUM] = 5,
+	},
+	[DPFE_CMD_GET_VENDOR] = {
+		[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+		[MSG_COMMAND] = 2,
+		[MSG_ARG_COUNT] = 1,
+		[MSG_ARG0] = 2,
+		[MSG_CHKSUM] = 6,
+	},
+};
+
+static void __disable_dcpu(void __iomem *regs)
+{
+	u32 val;
+
+	/* Check if DCPU is running */
+	val = readl_relaxed(regs + REG_DCPU_RESET);
+	if (!(val & DCPU_RESET_MASK)) {
+		/* Put DCPU in reset */
+		val |= (1 << DCPU_RESET_SHIFT);
+		writel_relaxed(val, regs + REG_DCPU_RESET);
+	}
+}
+
+static void __enable_dcpu(void __iomem *regs)
+{
+	u32 val;
+
+	/* Clear mailbox registers. */
+	writel_relaxed(0, regs + REG_TO_DCPU_MBOX);
+	writel_relaxed(0, regs + REG_TO_HOST_MBOX);
+
+	/* Disable DCPU clock gating */
+	val = readl_relaxed(regs + REG_DCPU_RESET);
+	val &= ~(1 << DCPU_CLK_DISABLE_SHIFT);
+	writel_relaxed(val, regs + REG_DCPU_RESET);
+
+	/* Take DCPU out of reset */
+	val = readl_relaxed(regs + REG_DCPU_RESET);
+	val &= ~(1 << DCPU_RESET_SHIFT);
+	writel_relaxed(val, regs + REG_DCPU_RESET);
+}
+
+static unsigned int get_msg_chksum(const u32 msg[])
+{
+	unsigned int sum = 0;
+	unsigned int i;
+
+	/* Don't include the last field in the checksum. */
+	for (i = 0; i < MSG_FIELD_MAX - 1; i++)
+		sum += msg[i];
+
+	return sum;
+}
+
+static int __send_command(struct private_data *priv, unsigned int cmd,
+			  u32 result[])
+{
+	const u32 *msg = dpfe_commands[cmd];
+	void __iomem *regs = priv->regs;
+	unsigned int i, chksum;
+	int ret = 0;
+	u32 resp;
+
+	if (cmd >= DPFE_CMD_MAX)
+		return -1;
+
+	mutex_lock(&priv->lock);
+
+	/* Write command and arguments to message area */
+	for (i = 0; i < MSG_FIELD_MAX; i++)
+		writel_relaxed(msg[i], regs + DCPU_MSG_RAM(i));
+
+	/* Tell DCPU there is a command waiting */
+	writel_relaxed(1, regs + REG_TO_DCPU_MBOX);
+
+	/* Wait for DCPU to process the command */
+	for (i = 0; i < DELAY_LOOP_MAX; i++) {
+		/* Read response code */
+		resp = readl_relaxed(regs + REG_TO_HOST_MBOX);
+		if (resp > 0)
+			break;
+		udelay(5);
+	}
+
+	if (i == DELAY_LOOP_MAX) {
+		resp = (DCPU_RET_ERR_TIMEDOUT & ~DCPU_RET_ERROR_BIT);
+		ret = -ffs(resp);
+	} else {
+		/* Read response data */
+		for (i = 0; i < MSG_FIELD_MAX; i++)
+			result[i] = readl_relaxed(regs + DCPU_MSG_RAM(i));
+	}
+
+	/* Tell DCPU we are done */
+	writel_relaxed(0, regs + REG_TO_HOST_MBOX);
+
+	mutex_unlock(&priv->lock);
+
+	if (ret)
+		return ret;
+
+	/* Verify response */
+	chksum = get_msg_chksum(result);
+	if (chksum != result[MSG_CHKSUM])
+		resp = DCPU_RET_ERR_CHKSUM;
+
+	if (resp != DCPU_RET_SUCCESS) {
+		resp &= ~DCPU_RET_ERROR_BIT;
+		ret = -ffs(resp);
+	}
+
+	return ret;
+}
+
+/* Ensure that the firmware file loaded meets all the requirements. */
+static int __verify_firmware(struct init_data *init,
+			     const struct firmware *fw)
+{
+	const struct dpfe_firmware_header *header = (void *)fw->data;
+	unsigned int dmem_size, imem_size, total_size;
+	bool is_big_endian = false;
+	const u32 *chksum_ptr;
+
+	if (header->magic == DPFE_BE_MAGIC)
+		is_big_endian = true;
+	else if (header->magic != DPFE_LE_MAGIC)
+		return ERR_INVALID_MAGIC;
+
+	if (is_big_endian) {
+		dmem_size = be32_to_cpu(header->dmem_size);
+		imem_size = be32_to_cpu(header->imem_size);
+	} else {
+		dmem_size = le32_to_cpu(header->dmem_size);
+		imem_size = le32_to_cpu(header->imem_size);
+	}
+
+	/* Data and instruction sections are 32 bit words. */
+	if ((dmem_size % sizeof(u32)) != 0 || (imem_size % sizeof(u32)) != 0)
+		return ERR_INVALID_SIZE;
+
+	/*
+	 * The header + the data section + the instruction section + the
+	 * checksum must be equal to the total firmware size.
+	 */
+	total_size = dmem_size + imem_size + sizeof(*header) +
+		sizeof(*chksum_ptr);
+	if (total_size != fw->size)
+		return ERR_INVALID_SIZE;
+
+	/* The checksum comes at the very end. */
+	chksum_ptr = (void *)fw->data + sizeof(*header) + dmem_size + imem_size;
+
+	init->is_big_endian = is_big_endian;
+	init->dmem_len = dmem_size;
+	init->imem_len = imem_size;
+	init->chksum = (is_big_endian)
+		? be32_to_cpu(*chksum_ptr) : le32_to_cpu(*chksum_ptr);
+
+	return 0;
+}
+
+/* Verify checksum by reading back the firmware from co-processor RAM. */
+static int __verify_fw_checksum(struct init_data *init,
+				struct private_data *priv,
+				const struct dpfe_firmware_header *header,
+				u32 checksum)
+{
+	u32 magic, sequence, version, sum;
+	u32 __iomem *dmem = priv->dmem;
+	u32 __iomem *imem = priv->imem;
+	unsigned int i;
+
+	if (init->is_big_endian) {
+		magic = be32_to_cpu(header->magic);
+		sequence = be32_to_cpu(header->sequence);
+		version = be32_to_cpu(header->version);
+	} else {
+		magic = le32_to_cpu(header->magic);
+		sequence = le32_to_cpu(header->sequence);
+		version = le32_to_cpu(header->version);
+	}
+
+	sum = magic + sequence + version + init->dmem_len + init->imem_len;
+
+	for (i = 0; i < init->dmem_len / sizeof(u32); i++)
+		sum += readl_relaxed(dmem + i);
+
+	for (i = 0; i < init->imem_len / sizeof(u32); i++)
+		sum += readl_relaxed(imem + i);
+
+	return (sum == checksum) ? 0 : -1;
+}
+
+static int __write_firmware(u32 __iomem *mem, const u32 *fw,
+			    unsigned int size, bool is_big_endian)
+{
+	unsigned int i;
+
+	/* Convert size to 32-bit words. */
+	size /= sizeof(u32);
+
+	/* It is recommended to clear the firmware area first. */
+	for (i = 0; i < size; i++)
+		writel_relaxed(0, mem + i);
+
+	/* Now copy it. */
+	if (is_big_endian) {
+		for (i = 0; i < size; i++)
+			writel_relaxed(be32_to_cpu(fw[i]), mem + i);
+	} else {
+		for (i = 0; i < size; i++)
+			writel_relaxed(le32_to_cpu(fw[i]), mem + i);
+	}
+
+	return 0;
+}
+
+static int brcmstb_dpfe_download_firmware(struct platform_device *pdev,
+					  struct init_data *init)
+{
+	const struct dpfe_firmware_header *header;
+	unsigned int dmem_size, imem_size;
+	struct device *dev = &pdev->dev;
+	bool is_big_endian = false;
+	struct private_data *priv;
+	const struct firmware *fw;
+	const u32 *dmem, *imem;
+	const void *fw_blob;
+	int ret;
+
+	ret = request_firmware(&fw, FIRMWARE_NAME, dev);
+	/* request_firmware() prints its own error messages. */
+	if (ret)
+		return ret;
+
+	priv = platform_get_drvdata(pdev);
+
+	ret = __verify_firmware(init, fw);
+	if (ret)
+		return -EFAULT;
+
+	__disable_dcpu(priv->regs);
+
+	is_big_endian = init->is_big_endian;
+	dmem_size = init->dmem_len;
+	imem_size = init->imem_len;
+
+	/* At the beginning of the firmware blob is a header. */
+	header = (struct dpfe_firmware_header *)fw->data;
+	/* Void pointer to the beginning of the actual firmware. */
+	fw_blob = fw->data + sizeof(*header);
+	/* IMEM comes right after the header. */
+	imem = fw_blob;
+	/* DMEM follows after IMEM. */
+	dmem = fw_blob + imem_size;
+
+	ret = __write_firmware(priv->dmem, dmem, dmem_size, is_big_endian);
+	if (ret)
+		return ret;
+	ret = __write_firmware(priv->imem, imem, imem_size, is_big_endian);
+	if (ret)
+		return ret;
+
+	ret = __verify_fw_checksum(init, priv, header, init->chksum);
+	if (ret)
+		return ret;
+
+	__enable_dcpu(priv->regs);
+
+	return 0;
+}
+
+static ssize_t generic_show(unsigned int command, u32 response[],
+			    struct device *dev, char *buf)
+{
+	struct private_data *priv;
+	int ret;
+
+	priv = dev_get_drvdata(dev);
+	if (!priv)
+		return sprintf(buf, "ERROR: driver private data not set\n");
+
+	ret = __send_command(priv, command, response);
+	if (ret < 0)
+		return sprintf(buf, "ERROR: %s\n", error_text[-ret]);
+
+	return 0;
+}
+
+static ssize_t show_info(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	unsigned int info;
+	int ret;
+
+	ret = generic_show(DPFE_CMD_GET_INFO, response, dev, buf);
+	if (ret)
+		return ret;
+
+	info = response[MSG_ARG0];
+
+	return sprintf(buf, "%u.%u.%u.%u\n",
+		       (info >> 24) & 0xff,
+		       (info >> 16) & 0xff,
+		       (info >> 8) & 0xff,
+		       info & 0xff);
+}
+
+static ssize_t show_refresh(struct device *dev,
+			    struct device_attribute *devattr, char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	void __iomem *info;
+	struct private_data *priv;
+	unsigned int offset;
+	u8 refresh, sr_abort, ppre, thermal_offs, tuf;
+	u32 mr4;
+	int ret;
+
+	ret = generic_show(DPFE_CMD_GET_REFRESH, response, dev, buf);
+	if (ret)
+		return ret;
+
+	priv = dev_get_drvdata(dev);
+	offset = response[MSG_ARG0];
+	info = priv->dmem + offset;
+
+	mr4 = readl_relaxed(info + DRAM_INFO_MR4) & DRAM_INFO_MR4_MASK;
+
+	refresh = (mr4 >> DRAM_MR4_REFRESH) & DRAM_MR4_REFRESH_MASK;
+	sr_abort = (mr4 >> DRAM_MR4_SR_ABORT) & DRAM_MR4_SR_ABORT_MASK;
+	ppre = (mr4 >> DRAM_MR4_PPRE) & DRAM_MR4_PPRE_MASK;
+	thermal_offs = (mr4 >> DRAM_MR4_TH_OFFS) & DRAM_MR4_TH_OFFS_MASK;
+	tuf = (mr4 >> DRAM_MR4_TUF) & DRAM_MR4_TUF_MASK;
+
+	return sprintf(buf, "%#x %#x %#x %#x %#x %#x %#x\n",
+		       readl_relaxed(info + DRAM_INFO_INTERVAL),
+		       refresh, sr_abort, ppre, thermal_offs, tuf,
+		       readl_relaxed(info + DRAM_INFO_ERROR));
+}
+
+static ssize_t store_refresh(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	u32 response[MSG_FIELD_MAX];
+	struct private_data *priv;
+	void __iomem *info;
+	unsigned int offset;
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	priv = dev_get_drvdata(dev);
+
+	ret = __send_command(priv, DPFE_CMD_GET_REFRESH, response);
+	if (ret)
+		return ret;
+
+	offset = response[MSG_ARG0];
+	info = priv->dmem + offset;
+	writel_relaxed(val, info + DRAM_INFO_INTERVAL);
+
+	return count;
+}
+
+static ssize_t show_vendor(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	struct private_data *priv;
+	void __iomem *info;
+	unsigned int offset;
+	int ret;
+
+	ret = generic_show(DPFE_CMD_GET_VENDOR, response, dev, buf);
+	if (ret)
+		return ret;
+
+	offset = response[MSG_ARG0];
+	priv = dev_get_drvdata(dev);
+	info = priv->dmem + offset;
+
+	return sprintf(buf, "%#x %#x %#x %#x %#x\n",
+		       readl_relaxed(info + DRAM_VENDOR_MR5) & DRAM_VENDOR_MASK,
+		       readl_relaxed(info + DRAM_VENDOR_MR6) & DRAM_VENDOR_MASK,
+		       readl_relaxed(info + DRAM_VENDOR_MR7) & DRAM_VENDOR_MASK,
+		       readl_relaxed(info + DRAM_VENDOR_MR8) & DRAM_VENDOR_MASK,
+		       readl_relaxed(info + DRAM_VENDOR_ERROR));
+}
+
+static int brcmstb_dpfe_resume(struct platform_device *pdev)
+{
+	struct init_data init;
+
+	return brcmstb_dpfe_download_firmware(pdev, &init);
+}
+
+static DEVICE_ATTR(dpfe_info, 0444, show_info, NULL);
+static DEVICE_ATTR(dpfe_refresh, 0644, show_refresh, store_refresh);
+static DEVICE_ATTR(dpfe_vendor, 0444, show_vendor, NULL);
+static struct attribute *dpfe_attrs[] = {
+	&dev_attr_dpfe_info.attr,
+	&dev_attr_dpfe_refresh.attr,
+	&dev_attr_dpfe_vendor.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(dpfe);
+
+static int brcmstb_dpfe_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct private_data *priv;
+	struct device *dpfe_dev;
+	struct init_data init;
+	struct resource *res;
+	u32 index;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->lock);
+	platform_set_drvdata(pdev, priv);
+
+	/* Cell index is optional; default to 0 if not present. */
+	ret = of_property_read_u32(dev->of_node, "cell-index", &index);
+	if (ret)
+		index = 0;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-cpu");
+	priv->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->regs)) {
+		dev_err(dev, "couldn't map DCPU registers\n");
+		return -ENODEV;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-dmem");
+	priv->dmem = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->dmem)) {
+		dev_err(dev, "Couldn't map DCPU data memory\n");
+		return -ENOENT;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-imem");
+	priv->imem = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->imem)) {
+		dev_err(dev, "Couldn't map DCPU instruction memory\n");
+		return -ENOENT;
+	}
+
+	ret = brcmstb_dpfe_download_firmware(pdev, &init);
+	if (ret)
+		goto err;
+
+	dpfe_dev = devm_kzalloc(dev, sizeof(*dpfe_dev), GFP_KERNEL);
+	if (!dpfe_dev) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	priv->dev = dpfe_dev;
+	priv->index = index;
+
+	dpfe_dev->parent = dev;
+	dpfe_dev->groups = dpfe_groups;
+	dpfe_dev->of_node = dev->of_node;
+	dev_set_drvdata(dpfe_dev, priv);
+	dev_set_name(dpfe_dev, "dpfe%u", index);
+
+	ret = device_register(dpfe_dev);
+	if (ret)
+		goto err;
+
+	dev_info(dev, "registered.\n");
+
+	return 0;
+
+err:
+	dev_err(dev, "failed to initialize -- error %d\n", ret);
+
+	return ret;
+}
+
+static const struct of_device_id brcmstb_dpfe_of_match[] = {
+	{ .compatible = "brcm,dpfe-cpu", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, brcmstb_dpfe_of_match);
+
+static struct platform_driver brcmstb_dpfe_driver = {
+	.driver	= {
+		.name = DRVNAME,
+		.of_match_table = brcmstb_dpfe_of_match,
+	},
+	.probe = brcmstb_dpfe_probe,
+	.resume = brcmstb_dpfe_resume,
+};
+
+module_platform_driver(brcmstb_dpfe_driver);
+
+MODULE_AUTHOR("Markus Mayer <[email-masked]>");
+MODULE_DESCRIPTION("BRCMSTB DDR PHY Front End Driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4