Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 947 insertions, 0 deletions

diff --git a/drivers/memory/brcmstb_dpfe.c b/drivers/memory/brcmstb_dpfe.c
new file mode 100644
index 0000000000..a7ab3d3772
--- /dev/null
+++ b/drivers/memory/brcmstb_dpfe.c
@@ -0,0 +1,947 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DDR PHY Front End (DPFE) driver for Broadcom set top box SoCs
+ *
+ * Copyright (c) 2017 Broadcom
+ */
+
+/*
+ * 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 firmware 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.h>
+#include <linux/platform_device.h>
+
+#define DRVNAME			"brcmstb-dpfe"
+
+/* DCPU register offsets */
+#define REG_DCPU_RESET		0x0
+#define REG_TO_DCPU_MBOX	0x10
+#define REG_TO_HOST_MBOX	0x14
+
+/* Macros to process offsets returned by the DCPU */
+#define DRAM_MSG_ADDR_OFFSET	0x0
+#define DRAM_MSG_TYPE_OFFSET	0x1c
+#define DRAM_MSG_ADDR_MASK	((1UL << DRAM_MSG_TYPE_OFFSET) - 1)
+#define DRAM_MSG_TYPE_MASK	((1UL << \
+				 (BITS_PER_LONG - DRAM_MSG_TYPE_OFFSET)) - 1)
+
+/* Message RAM */
+#define DCPU_MSG_RAM_START	0x100
+#define DCPU_MSG_RAM(x)		(DCPU_MSG_RAM_START + (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
+#define DRAM_INFO_MR4_SHIFT	24	/* We need to look at byte 3 */
+
+/* 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 (API v2) */
+#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
+#define DRAM_VENDOR_SHIFT	24	/* We need to look at byte 3 */
+
+/* DRAM Information Offsets & Masks (API v3) */
+#define DRAM_DDR_INFO_MR4	0x0
+#define DRAM_DDR_INFO_MR5	0x4
+#define DRAM_DDR_INFO_MR6	0x8
+#define DRAM_DDR_INFO_MR7	0xc
+#define DRAM_DDR_INFO_MR8	0x10
+#define DRAM_DDR_INFO_ERROR	0x14
+#define DRAM_DDR_INFO_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		1000
+
+enum dpfe_msg_fields {
+	MSG_HEADER,
+	MSG_COMMAND,
+	MSG_ARG_COUNT,
+	MSG_ARG0,
+	MSG_FIELD_MAX	= 16 /* Max number of arguments */
+};
+
+enum dpfe_commands {
+	DPFE_CMD_GET_INFO,
+	DPFE_CMD_GET_REFRESH,
+	DPFE_CMD_GET_VENDOR,
+	DPFE_CMD_MAX /* Last entry */
+};
+
+/*
+ * 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;
+};
+
+/* API version and corresponding commands */
+struct dpfe_api {
+	int version;
+	const char *fw_name;
+	const struct attribute_group **sysfs_attrs;
+	u32 command[DPFE_CMD_MAX][MSG_FIELD_MAX];
+};
+
+/* Things we need for as long as we are active. */
+struct brcmstb_dpfe_priv {
+	void __iomem *regs;
+	void __iomem *dmem;
+	void __iomem *imem;
+	struct device *dev;
+	const struct dpfe_api *dpfe_api;
+	struct mutex lock;
+};
+
+/*
+ * Forward declaration of our sysfs attribute functions, so we can declare the
+ * attribute data structures early.
+ */
+static ssize_t show_info(struct device *, struct device_attribute *, char *);
+static ssize_t show_refresh(struct device *, struct device_attribute *, char *);
+static ssize_t store_refresh(struct device *, struct device_attribute *,
+			  const char *, size_t);
+static ssize_t show_vendor(struct device *, struct device_attribute *, char *);
+static ssize_t show_dram(struct device *, struct device_attribute *, char *);
+
+/*
+ * Declare our attributes early, so they can be referenced in the API data
+ * structure. We need to do this, because the attributes depend on the API
+ * version.
+ */
+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 DEVICE_ATTR(dpfe_dram, 0444, show_dram, NULL);
+
+/* API v2 sysfs attributes */
+static struct attribute *dpfe_v2_attrs[] = {
+	&dev_attr_dpfe_info.attr,
+	&dev_attr_dpfe_refresh.attr,
+	&dev_attr_dpfe_vendor.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(dpfe_v2);
+
+/* API v3 sysfs attributes */
+static struct attribute *dpfe_v3_attrs[] = {
+	&dev_attr_dpfe_info.attr,
+	&dev_attr_dpfe_dram.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(dpfe_v3);
+
+/*
+ * Old API v2 firmware commands, as defined in the rev 0.61 specification, we
+ * use a version set to 1 to denote that it is not compatible with the new API
+ * v2 and onwards.
+ */
+static const struct dpfe_api dpfe_api_old_v2 = {
+	.version = 1,
+	.fw_name = "dpfe.bin",
+	.sysfs_attrs = dpfe_v2_groups,
+	.command = {
+		[DPFE_CMD_GET_INFO] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 1,
+			[MSG_ARG_COUNT] = 1,
+			[MSG_ARG0] = 1,
+		},
+		[DPFE_CMD_GET_REFRESH] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 2,
+			[MSG_ARG_COUNT] = 1,
+			[MSG_ARG0] = 1,
+		},
+		[DPFE_CMD_GET_VENDOR] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 2,
+			[MSG_ARG_COUNT] = 1,
+			[MSG_ARG0] = 2,
+		},
+	}
+};
+
+/*
+ * API v2 firmware commands, as defined in the rev 0.8 specification, named new
+ * v2 here
+ */
+static const struct dpfe_api dpfe_api_new_v2 = {
+	.version = 2,
+	.fw_name = NULL, /* We expect the firmware to have been downloaded! */
+	.sysfs_attrs = dpfe_v2_groups,
+	.command = {
+		[DPFE_CMD_GET_INFO] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x101,
+		},
+		[DPFE_CMD_GET_REFRESH] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x201,
+		},
+		[DPFE_CMD_GET_VENDOR] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x202,
+		},
+	}
+};
+
+/* API v3 firmware commands */
+static const struct dpfe_api dpfe_api_v3 = {
+	.version = 3,
+	.fw_name = NULL, /* We expect the firmware to have been downloaded! */
+	.sysfs_attrs = dpfe_v3_groups,
+	.command = {
+		[DPFE_CMD_GET_INFO] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x0101,
+			[MSG_ARG_COUNT] = 1,
+			[MSG_ARG0] = 1,
+		},
+		[DPFE_CMD_GET_REFRESH] = {
+			[MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
+			[MSG_COMMAND] = 0x0202,
+			[MSG_ARG_COUNT] = 0,
+		},
+		/* There's no GET_VENDOR command in API v3. */
+	},
+};
+
+static const char *get_error_text(unsigned int i)
+{
+	static const char * const error_text[] = {
+		"Success", "Header code incorrect",
+		"Unknown command or argument", "Incorrect checksum",
+		"Malformed command", "Timed out", "Unknown error",
+	};
+
+	if (unlikely(i >= ARRAY_SIZE(error_text)))
+		i = ARRAY_SIZE(error_text) - 1;
+
+	return error_text[i];
+}
+
+static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
+{
+	u32 val;
+
+	mutex_lock(&priv->lock);
+	val = readl_relaxed(priv->regs + REG_DCPU_RESET);
+	mutex_unlock(&priv->lock);
+
+	return !(val & DCPU_RESET_MASK);
+}
+
+static void __disable_dcpu(struct brcmstb_dpfe_priv *priv)
+{
+	u32 val;
+
+	if (!is_dcpu_enabled(priv))
+		return;
+
+	mutex_lock(&priv->lock);
+
+	/* Put DCPU in reset if it's running. */
+	val = readl_relaxed(priv->regs + REG_DCPU_RESET);
+	val |= (1 << DCPU_RESET_SHIFT);
+	writel_relaxed(val, priv->regs + REG_DCPU_RESET);
+
+	mutex_unlock(&priv->lock);
+}
+
+static void __enable_dcpu(struct brcmstb_dpfe_priv *priv)
+{
+	void __iomem *regs = priv->regs;
+	u32 val;
+
+	mutex_lock(&priv->lock);
+
+	/* 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);
+
+	mutex_unlock(&priv->lock);
+}
+
+static unsigned int get_msg_chksum(const u32 msg[], unsigned int max)
+{
+	unsigned int sum = 0;
+	unsigned int i;
+
+	/* Don't include the last field in the checksum. */
+	for (i = 0; i < max; i++)
+		sum += msg[i];
+
+	return sum;
+}
+
+static void __iomem *get_msg_ptr(struct brcmstb_dpfe_priv *priv, u32 response,
+				 char *buf, ssize_t *size)
+{
+	unsigned int msg_type;
+	unsigned int offset;
+	void __iomem *ptr = NULL;
+
+	/* There is no need to use this function for API v3 or later. */
+	if (unlikely(priv->dpfe_api->version >= 3))
+		return NULL;
+
+	msg_type = (response >> DRAM_MSG_TYPE_OFFSET) & DRAM_MSG_TYPE_MASK;
+	offset = (response >> DRAM_MSG_ADDR_OFFSET) & DRAM_MSG_ADDR_MASK;
+
+	/*
+	 * msg_type == 1: the offset is relative to the message RAM
+	 * msg_type == 0: the offset is relative to the data RAM (this is the
+	 *                previous way of passing data)
+	 * msg_type is anything else: there's critical hardware problem
+	 */
+	switch (msg_type) {
+	case 1:
+		ptr = priv->regs + DCPU_MSG_RAM_START + offset;
+		break;
+	case 0:
+		ptr = priv->dmem + offset;
+		break;
+	default:
+		dev_emerg(priv->dev, "invalid message reply from DCPU: %#x\n",
+			response);
+		if (buf && size)
+			*size = sprintf(buf,
+				"FATAL: communication error with DCPU\n");
+	}
+
+	return ptr;
+}
+
+static void __finalize_command(struct brcmstb_dpfe_priv *priv)
+{
+	unsigned int release_mbox;
+
+	/*
+	 * It depends on the API version which MBOX register we have to write to
+	 * signal we are done.
+	 */
+	release_mbox = (priv->dpfe_api->version < 2)
+			? REG_TO_HOST_MBOX : REG_TO_DCPU_MBOX;
+	writel_relaxed(0, priv->regs + release_mbox);
+}
+
+static int __send_command(struct brcmstb_dpfe_priv *priv, unsigned int cmd,
+			  u32 result[])
+{
+	void __iomem *regs = priv->regs;
+	unsigned int i, chksum, chksum_idx;
+	const u32 *msg;
+	int ret = 0;
+	u32 resp;
+
+	if (cmd >= DPFE_CMD_MAX)
+		return -1;
+
+	msg = priv->dpfe_api->command[cmd];
+
+	mutex_lock(&priv->lock);
+
+	/* Wait for DCPU to become ready */
+	for (i = 0; i < DELAY_LOOP_MAX; i++) {
+		resp = readl_relaxed(regs + REG_TO_HOST_MBOX);
+		if (resp == 0)
+			break;
+		msleep(1);
+	}
+	if (resp != 0) {
+		mutex_unlock(&priv->lock);
+		return -ffs(DCPU_RET_ERR_TIMEDOUT);
+	}
+
+	/* Compute checksum over the message */
+	chksum_idx = msg[MSG_ARG_COUNT] + MSG_ARG_COUNT + 1;
+	chksum = get_msg_chksum(msg, chksum_idx);
+
+	/* Write command and arguments to message area */
+	for (i = 0; i < MSG_FIELD_MAX; i++) {
+		if (i == chksum_idx)
+			writel_relaxed(chksum, regs + DCPU_MSG_RAM(i));
+		else
+			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;
+		msleep(1);
+	}
+
+	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));
+		chksum_idx = result[MSG_ARG_COUNT] + MSG_ARG_COUNT + 1;
+	}
+
+	/* Tell DCPU we are done */
+	__finalize_command(priv);
+
+	mutex_unlock(&priv->lock);
+
+	if (ret)
+		return ret;
+
+	/* Verify response */
+	chksum = get_msg_chksum(result, chksum_idx);
+	if (chksum != result[chksum_idx])
+		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 brcmstb_dpfe_priv *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 brcmstb_dpfe_priv *priv)
+{
+	const struct dpfe_firmware_header *header;
+	unsigned int dmem_size, imem_size;
+	struct device *dev = priv->dev;
+	bool is_big_endian = false;
+	const struct firmware *fw;
+	const u32 *dmem, *imem;
+	struct init_data init;
+	const void *fw_blob;
+	int ret;
+
+	/*
+	 * Skip downloading the firmware if the DCPU is already running and
+	 * responding to commands.
+	 */
+	if (is_dcpu_enabled(priv)) {
+		u32 response[MSG_FIELD_MAX];
+
+		ret = __send_command(priv, DPFE_CMD_GET_INFO, response);
+		if (!ret)
+			return 0;
+	}
+
+	/*
+	 * If the firmware filename is NULL it means the boot firmware has to
+	 * download the DCPU firmware for us. If that didn't work, we have to
+	 * bail, since downloading it ourselves wouldn't work either.
+	 */
+	if (!priv->dpfe_api->fw_name)
+		return -ENODEV;
+
+	ret = firmware_request_nowarn(&fw, priv->dpfe_api->fw_name, dev);
+	/*
+	 * Defer the firmware download if the firmware file couldn't be found.
+	 * The root file system may not be available yet.
+	 */
+	if (ret)
+		return (ret == -ENOENT) ? -EPROBE_DEFER : ret;
+
+	ret = __verify_firmware(&init, fw);
+	if (ret) {
+		ret = -EFAULT;
+		goto release_fw;
+	}
+
+	__disable_dcpu(priv);
+
+	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)
+		goto release_fw;
+	ret = __write_firmware(priv->imem, imem, imem_size, is_big_endian);
+	if (ret)
+		goto release_fw;
+
+	ret = __verify_fw_checksum(&init, priv, header, init.chksum);
+	if (ret)
+		goto release_fw;
+
+	__enable_dcpu(priv);
+
+release_fw:
+	release_firmware(fw);
+	return ret;
+}
+
+static ssize_t generic_show(unsigned int command, u32 response[],
+			    struct brcmstb_dpfe_priv *priv, char *buf)
+{
+	int ret;
+
+	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", get_error_text(-ret));
+
+	return 0;
+}
+
+static ssize_t show_info(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	struct brcmstb_dpfe_priv *priv;
+	unsigned int info;
+	ssize_t ret;
+
+	priv = dev_get_drvdata(dev);
+	ret = generic_show(DPFE_CMD_GET_INFO, response, priv, 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 brcmstb_dpfe_priv *priv;
+	u8 refresh, sr_abort, ppre, thermal_offs, tuf;
+	u32 mr4;
+	ssize_t ret;
+
+	priv = dev_get_drvdata(dev);
+	ret = generic_show(DPFE_CMD_GET_REFRESH, response, priv, buf);
+	if (ret)
+		return ret;
+
+	info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
+	if (!info)
+		return ret;
+
+	mr4 = (readl_relaxed(info + DRAM_INFO_MR4) >> DRAM_INFO_MR4_SHIFT) &
+	       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 brcmstb_dpfe_priv *priv;
+	void __iomem *info;
+	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;
+
+	info = get_msg_ptr(priv, response[MSG_ARG0], NULL, NULL);
+	if (!info)
+		return -EIO;
+
+	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 brcmstb_dpfe_priv *priv;
+	void __iomem *info;
+	ssize_t ret;
+	u32 mr5, mr6, mr7, mr8, err;
+
+	priv = dev_get_drvdata(dev);
+	ret = generic_show(DPFE_CMD_GET_VENDOR, response, priv, buf);
+	if (ret)
+		return ret;
+
+	info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
+	if (!info)
+		return ret;
+
+	mr5 = (readl_relaxed(info + DRAM_VENDOR_MR5) >> DRAM_VENDOR_SHIFT) &
+		DRAM_VENDOR_MASK;
+	mr6 = (readl_relaxed(info + DRAM_VENDOR_MR6) >> DRAM_VENDOR_SHIFT) &
+		DRAM_VENDOR_MASK;
+	mr7 = (readl_relaxed(info + DRAM_VENDOR_MR7) >> DRAM_VENDOR_SHIFT) &
+		DRAM_VENDOR_MASK;
+	mr8 = (readl_relaxed(info + DRAM_VENDOR_MR8) >> DRAM_VENDOR_SHIFT) &
+		DRAM_VENDOR_MASK;
+	err = readl_relaxed(info + DRAM_VENDOR_ERROR) & DRAM_VENDOR_MASK;
+
+	return sprintf(buf, "%#x %#x %#x %#x %#x\n", mr5, mr6, mr7, mr8, err);
+}
+
+static ssize_t show_dram(struct device *dev, struct device_attribute *devattr,
+			 char *buf)
+{
+	u32 response[MSG_FIELD_MAX];
+	struct brcmstb_dpfe_priv *priv;
+	ssize_t ret;
+	u32 mr4, mr5, mr6, mr7, mr8, err;
+
+	priv = dev_get_drvdata(dev);
+	ret = generic_show(DPFE_CMD_GET_REFRESH, response, priv, buf);
+	if (ret)
+		return ret;
+
+	mr4 = response[MSG_ARG0 + 0] & DRAM_INFO_MR4_MASK;
+	mr5 = response[MSG_ARG0 + 1] & DRAM_DDR_INFO_MASK;
+	mr6 = response[MSG_ARG0 + 2] & DRAM_DDR_INFO_MASK;
+	mr7 = response[MSG_ARG0 + 3] & DRAM_DDR_INFO_MASK;
+	mr8 = response[MSG_ARG0 + 4] & DRAM_DDR_INFO_MASK;
+	err = response[MSG_ARG0 + 5] & DRAM_DDR_INFO_MASK;
+
+	return sprintf(buf, "%#x %#x %#x %#x %#x %#x\n", mr4, mr5, mr6, mr7,
+			mr8, err);
+}
+
+static int brcmstb_dpfe_resume(struct platform_device *pdev)
+{
+	struct brcmstb_dpfe_priv *priv = platform_get_drvdata(pdev);
+
+	return brcmstb_dpfe_download_firmware(priv);
+}
+
+static int brcmstb_dpfe_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct brcmstb_dpfe_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	mutex_init(&priv->lock);
+	platform_set_drvdata(pdev, priv);
+
+	priv->regs = devm_platform_ioremap_resource_byname(pdev, "dpfe-cpu");
+	if (IS_ERR(priv->regs)) {
+		dev_err(dev, "couldn't map DCPU registers\n");
+		return -ENODEV;
+	}
+
+	priv->dmem = devm_platform_ioremap_resource_byname(pdev, "dpfe-dmem");
+	if (IS_ERR(priv->dmem)) {
+		dev_err(dev, "Couldn't map DCPU data memory\n");
+		return -ENOENT;
+	}
+
+	priv->imem = devm_platform_ioremap_resource_byname(pdev, "dpfe-imem");
+	if (IS_ERR(priv->imem)) {
+		dev_err(dev, "Couldn't map DCPU instruction memory\n");
+		return -ENOENT;
+	}
+
+	priv->dpfe_api = of_device_get_match_data(dev);
+	if (unlikely(!priv->dpfe_api)) {
+		/*
+		 * It should be impossible to end up here, but to be safe we
+		 * check anyway.
+		 */
+		dev_err(dev, "Couldn't determine API\n");
+		return -ENOENT;
+	}
+
+	ret = brcmstb_dpfe_download_firmware(priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Couldn't download firmware\n");
+
+	ret = sysfs_create_groups(&pdev->dev.kobj, priv->dpfe_api->sysfs_attrs);
+	if (!ret)
+		dev_info(dev, "registered with API v%d.\n",
+			 priv->dpfe_api->version);
+
+	return ret;
+}
+
+static int brcmstb_dpfe_remove(struct platform_device *pdev)
+{
+	struct brcmstb_dpfe_priv *priv = dev_get_drvdata(&pdev->dev);
+
+	sysfs_remove_groups(&pdev->dev.kobj, priv->dpfe_api->sysfs_attrs);
+
+	return 0;
+}
+
+static const struct of_device_id brcmstb_dpfe_of_match[] = {
+	/* Use legacy API v2 for a select number of chips */
+	{ .compatible = "brcm,bcm7268-dpfe-cpu", .data = &dpfe_api_old_v2 },
+	{ .compatible = "brcm,bcm7271-dpfe-cpu", .data = &dpfe_api_old_v2 },
+	{ .compatible = "brcm,bcm7278-dpfe-cpu", .data = &dpfe_api_old_v2 },
+	{ .compatible = "brcm,bcm7211-dpfe-cpu", .data = &dpfe_api_new_v2 },
+	/* API v3 is the default going forward */
+	{ .compatible = "brcm,dpfe-cpu", .data = &dpfe_api_v3 },
+	{}
+};
+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,
+	.remove	= brcmstb_dpfe_remove,
+	.resume = brcmstb_dpfe_resume,
+};
+
+module_platform_driver(brcmstb_dpfe_driver);
+
+MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
+MODULE_DESCRIPTION("BRCMSTB DDR PHY Front End Driver");
+MODULE_LICENSE("GPL");