diff options
author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2020-05-26 15:59:28 +0300 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2020-05-28 15:17:41 +0300 |
commit | 83ca8b3e8f213f49cc68b5c1fbcf88ebb24671eb (patch) | |
tree | bd2e9caa7cf5294ac4906ac560abdddda5cd3dc3 /drivers/memory/bt1-l2-ctl.c | |
parent | 8f93662d8324940e8925a0e492c587dbcf7c7fee (diff) |
memory: Add Baikal-T1 L2-cache Control Block driver
Baikal-T1 SoC provides a way to tune the MIPS P5600 CM2 L2-cache
performance up. It can be done by changing the L2-RAM Data/Tag/WS
latencies in a dedicated register exposed by the system controller.
The driver added by this commit provides a dts properties-based and
sysfs-based interface for it. The device DT node is supposed to be a
child of Baikal-T1 System Controller node.
Link: https://lore.kernel.org/r/20200526125928.17096-7-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: soc@kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'drivers/memory/bt1-l2-ctl.c')
-rw-r--r-- | drivers/memory/bt1-l2-ctl.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/drivers/memory/bt1-l2-ctl.c b/drivers/memory/bt1-l2-ctl.c new file mode 100644 index 000000000000..633fea6a4edf --- /dev/null +++ b/drivers/memory/bt1-l2-ctl.c @@ -0,0 +1,322 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC + * + * Authors: + * Serge Semin <Sergey.Semin@baikalelectronics.ru> + * + * 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 <Sergey.Semin@baikalelectronics.ru>"); +MODULE_DESCRIPTION("Baikal-T1 L2-cache driver"); +MODULE_LICENSE("GPL v2"); |