// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
*
* Authors:
* Serge Semin <[email protected]>
*
* Baikal-T1 CM2 L2-cache Control Block driver.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bitfield.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
#include <linux/sysfs.h>
#include <linux/of.h>
#define L2_CTL_REG 0x028
#define L2_CTL_DATA_STALL_FLD 0
#define L2_CTL_DATA_STALL_MASK GENMASK(1, L2_CTL_DATA_STALL_FLD)
#define L2_CTL_TAG_STALL_FLD 2
#define L2_CTL_TAG_STALL_MASK GENMASK(3, L2_CTL_TAG_STALL_FLD)
#define L2_CTL_WS_STALL_FLD 4
#define L2_CTL_WS_STALL_MASK GENMASK(5, L2_CTL_WS_STALL_FLD)
#define L2_CTL_SET_CLKRATIO BIT(13)
#define L2_CTL_CLKRATIO_LOCK BIT(31)
#define L2_CTL_STALL_MIN 0
#define L2_CTL_STALL_MAX 3
#define L2_CTL_STALL_SET_DELAY_US 1
#define L2_CTL_STALL_SET_TOUT_US 1000
/*
* struct l2_ctl - Baikal-T1 L2 Control block private data.
* @dev: Pointer to the device structure.
* @sys_regs: Baikal-T1 System Controller registers map.
*/
struct l2_ctl {
struct device *dev;
struct regmap *sys_regs;
};
/*
* enum l2_ctl_stall - Baikal-T1 L2-cache-RAM stall identifier.
* @L2_WSSTALL: Way-select latency.
* @L2_TAGSTALL: Tag latency.
* @L2_DATASTALL: Data latency.
*/
enum l2_ctl_stall {
L2_WS_STALL,
L2_TAG_STALL,
L2_DATA_STALL
};
/*
* struct l2_ctl_device_attribute - Baikal-T1 L2-cache device attribute.
* @dev_attr: Actual sysfs device attribute.
* @id: L2-cache stall field identifier.
*/
struct l2_ctl_device_attribute {
struct device_attribute dev_attr;
enum l2_ctl_stall id;
};
#define to_l2_ctl_dev_attr(_dev_attr) \
container_of(_dev_attr, struct l2_ctl_device_attribute, dev_attr)
#define L2_CTL_ATTR_RW(_name, _prefix, _id) \
struct l2_ctl_device_attribute l2_ctl_attr_##_name = \
{ __ATTR(_name, 0644, _prefix##_show, _prefix##_store), _id }
static int l2_ctl_get_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 *val)
{
u32 data = 0;
int ret;
ret = regmap_read(l2->sys_regs, L2_CTL_REG, &data);
if (ret)
return ret;
switch (id) {
case L2_WS_STALL:
*val = FIELD_GET(L2_CTL_WS_STALL_MASK, data);
break;
case L2_TAG_STALL:
*val = FIELD_GET(L2_CTL_TAG_STALL_MASK, data);
break;
case L2_DATA_STALL:
*val = FIELD_GET(L2_CTL_DATA_STALL_MASK, data);
break;
default:
return -EINVAL;
}
return 0;
}
static int l2_ctl_set_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 val)
{
u32 mask = 0, data = 0;
int ret;
val = clamp_val(val, L2_CTL_STALL_MIN, L2_CTL_STALL_MAX);
switch (id) {
case L2_WS_STALL:
data = FIELD_PREP(L2_CTL_WS_STALL_MASK, val);
mask = L2_CTL_WS_STALL_MASK;
break;
case L2_TAG_STALL:
data = FIELD_PREP(L2_CTL_TAG_STALL_MASK, val);
mask = L2_CTL_TAG_STALL_MASK;
break;
case L2_DATA_STALL:
data = FIELD_PREP(L2_CTL_DATA_STALL_MASK, val);
mask = L2_CTL_DATA_STALL_MASK;
break;
default:
return -EINVAL;
}
data |= L2_CTL_SET_CLKRATIO;
mask |= L2_CTL_SET_CLKRATIO;
ret = regmap_update_bits(l2->sys_regs, L2_CTL_REG, mask, data);
if (ret)
return ret;
return regmap_read_poll_timeout(l2->sys_regs, L2_CTL_REG, data,
data & L2_CTL_CLKRATIO_LOCK,
L2_CTL_STALL_SET_DELAY_US,
L2_CTL_STALL_SET_TOUT_US);
}
static void l2_ctl_clear_data(void *data)
{
struct l2_ctl *l2 = data;
struct platform_device *pdev = to_platform_device(l2->dev);
platform_set_drvdata(pdev, NULL);
}
static struct l2_ctl *l2_ctl_create_data(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct l2_ctl *l2;
int ret;
l2 = devm_kzalloc(dev, sizeof(*l2), GFP_KERNEL);
if (!l2)
return ERR_PTR(-ENOMEM);
ret = devm_add_action(dev, l2_ctl_clear_data, l2);
if (ret) {
dev_err(dev, "Can't add L2 CTL data clear action\n");
return ERR_PTR(ret);
}
l2->dev = dev;
platform_set_drvdata(pdev, l2);
return l2;
}
static int l2_ctl_find_sys_regs(struct l2_ctl *l2)
{
l2->sys_regs = syscon_node_to_regmap(l2->dev->of_node->parent);
if (IS_ERR(l2->sys_regs)) {
dev_err(l2->dev, "Couldn't get L2 CTL register map\n");
return PTR_ERR(l2->sys_regs);
}
return 0;
}
static int l2_ctl_of_parse_property(struct l2_ctl *l2, enum l2_ctl_stall id,
const char *propname)
{
int ret = 0;
u32 data;
if (!of_property_read_u32(l2->dev->of_node, propname, &data)) {
ret = l2_ctl_set_latency(l2, id, data);
if (ret)
dev_err(l2->dev, "Invalid value of '%s'\n", propname);
}
return ret;
}
static int l2_ctl_of_parse(struct l2_ctl *l2)
{
int ret;
ret = l2_ctl_of_parse_property(l2, L2_WS_STALL, "baikal,l2-ws-latency");
if (ret)
return ret;
ret = l2_ctl_of_parse_property(l2, L2_TAG_STALL, "baikal,l2-tag-latency");
if (ret)
return ret;
return l2_ctl_of_parse_property(l2, L2_DATA_STALL,
"baikal,l2-data-latency");
}
static ssize_t l2_ctl_latency_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
struct l2_ctl *l2 = dev_get_drvdata(dev);
u32 data;
int ret;
ret = l2_ctl_get_latency(l2, devattr->id, &data);
if (ret)
return ret;
return scnprintf(buf, PAGE_SIZE, "%u\n", data);
}
static ssize_t l2_ctl_latency_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
struct l2_ctl *l2 = dev_get_drvdata(dev);
u32 data;
int ret;
if (kstrtouint(buf, 0, &data) < 0)
return -EINVAL;
ret = l2_ctl_set_latency(l2, devattr->id, data);
if (ret)
return ret;
return count;
}
static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
static struct attribute *l2_ctl_sysfs_attrs[] = {
&l2_ctl_attr_l2_ws_latency.dev_attr.attr,
&l2_ctl_attr_l2_tag_latency.dev_attr.attr,
&l2_ctl_attr_l2_data_latency.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(l2_ctl_sysfs);
static void l2_ctl_remove_sysfs(void *data)
{
struct l2_ctl *l2 = data;
device_remove_groups(l2->dev, l2_ctl_sysfs_groups);
}
static int l2_ctl_init_sysfs(struct l2_ctl *l2)
{
int ret;
ret = device_add_groups(l2->dev, l2_ctl_sysfs_groups);
if (ret) {
dev_err(l2->dev, "Failed to create L2 CTL sysfs nodes\n");
return ret;
}
ret = devm_add_action_or_reset(l2->dev, l2_ctl_remove_sysfs, l2);
if (ret)
dev_err(l2->dev, "Can't add L2 CTL sysfs remove action\n");
return ret;
}
static int l2_ctl_probe(struct platform_device *pdev)
{
struct l2_ctl *l2;
int ret;
l2 = l2_ctl_create_data(pdev);
if (IS_ERR(l2))
return PTR_ERR(l2);
ret = l2_ctl_find_sys_regs(l2);
if (ret)
return ret;
ret = l2_ctl_of_parse(l2);
if (ret)
return ret;
ret = l2_ctl_init_sysfs(l2);
if (ret)
return ret;
return 0;
}
static const struct of_device_id l2_ctl_of_match[] = {
{ .compatible = "baikal,bt1-l2-ctl" },
{ }
};
MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
static struct platform_driver l2_ctl_driver = {
.probe = l2_ctl_probe,
.driver = {
.name = "bt1-l2-ctl",
.of_match_table = l2_ctl_of_match
}
};
module_platform_driver(l2_ctl_driver);
MODULE_AUTHOR("Serge Semin <[email protected]>");
MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
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