/*
* 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
/* 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
/* 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;
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 bool is_dcpu_enabled(void __iomem *regs)
{
u32 val;
val = readl_relaxed(regs + REG_DCPU_RESET);
return !(val & DCPU_RESET_MASK);
}
static void __disable_dcpu(void __iomem *regs)
{
u32 val;
if (!is_dcpu_enabled(regs))
return;
/* Put DCPU in reset if it's running. */
val = readl_relaxed(regs + REG_DCPU_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 void __iomem *get_msg_ptr(struct private_data *priv, u32 response,
char *buf, ssize_t *size)
{
unsigned int msg_type;
unsigned int offset;
void __iomem *ptr = 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 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;
priv = platform_get_drvdata(pdev);
/*
* Skip downloading the firmware if the DCPU is already running and
* responding to commands.
*/
if (is_dcpu_enabled(priv->regs)) {
u32 response[MSG_FIELD_MAX];
ret = __send_command(priv, DPFE_CMD_GET_INFO, response);
if (!ret)
return 0;
}
ret = request_firmware(&fw, FIRMWARE_NAME, dev);
/* request_firmware() prints its own error messages. */
if (ret)
return ret;
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;
ssize_t 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;
u8 refresh, sr_abort, ppre, thermal_offs, tuf;
u32 mr4;
ssize_t ret;
ret = generic_show(DPFE_CMD_GET_REFRESH, response, dev, buf);
if (ret)
return ret;
priv = dev_get_drvdata(dev);
info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
if (!info)
return ret;
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 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 private_data *priv;
void __iomem *info;
ssize_t ret;
ret = generic_show(DPFE_CMD_GET_VENDOR, response, dev, buf);
if (ret)
return ret;
priv = dev_get_drvdata(dev);
info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
if (!info)
return ret;
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) &
DRAM_VENDOR_MASK);
}
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 init_data init;
struct resource *res;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
mutex_init(&priv->lock);
platform_set_drvdata(pdev, priv);
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)
return ret;
ret = sysfs_create_groups(&pdev->dev.kobj, dpfe_groups);
if (!ret)
dev_info(dev, "registered.\n");
return ret;
}
static int brcmstb_dpfe_remove(struct platform_device *pdev)
{
sysfs_remove_groups(&pdev->dev.kobj, dpfe_groups);
return 0;
}
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,
.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");
