[RFC PATCH 3/4] misc: Add bmc-misc-ctrl
Andrew Jeffery
andrew at aj.id.au
Tue Jul 3 17:04:12 AEST 2018
bmc-misc-ctrl is used to expose miscellaneous Baseboard
Management Controller (BMC) hardware features described in the devicetree
to userspace.
Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
---
MAINTAINERS | 1 +
drivers/misc/Kconfig | 8 +
drivers/misc/Makefile | 1 +
drivers/misc/bmc-misc-ctrl.c | 363 +++++++++++++++++++++++++++++++++++
4 files changed, 373 insertions(+)
create mode 100644 drivers/misc/bmc-misc-ctrl.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 9766d7832d8b..30d39440b6f2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2741,6 +2741,7 @@ R: Andrew Jeffery <andrew at aj.id.au>
L: openbmc at lists.ozlabs.org (moderated for non-subscribers)
S: Supported
F: Documentation/devicetree/bindings/misc/bmc-misc-ctrl.txt
+F: drivers/misc/bmc-misc-ctrl.c
BPF (Safe dynamic programs and tools)
M: Alexei Starovoitov <ast at kernel.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 3726eacdf65d..f46bc8208b50 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -513,6 +513,14 @@ config MISC_RTSX
tristate
default MISC_RTSX_PCI || MISC_RTSX_USB
+config BMC_MISC_CTRL
+ tristate "Miscellaneous BMC Control Interfaces"
+ depends on REGMAP && MFD_SYSCON
+ help
+ Say yes to expose scratch registers used to communicate between the
+ host and BMC along with other miscellaneous control interfaces
+ provided by BMC SoCs
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index af22bbc3d00c..4fb2fac7a486 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -58,3 +58,4 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o
obj-$(CONFIG_OCXL) += ocxl/
obj-$(CONFIG_MISC_RTSX) += cardreader/
+obj-$(CONFIG_BMC_MISC_CTRL) += bmc-misc-ctrl.o
diff --git a/drivers/misc/bmc-misc-ctrl.c b/drivers/misc/bmc-misc-ctrl.c
new file mode 100644
index 000000000000..ff907029163f
--- /dev/null
+++ b/drivers/misc/bmc-misc-ctrl.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2018 IBM Corp.
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/kobject.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+struct bmc_ctrl {
+ struct device *dev;
+ struct regmap *map;
+ bool ro;
+ u32 shift;
+ u32 mask;
+ struct kobj_attribute mask_attr;
+ const char *label;
+ struct kobj_attribute label_attr;
+ union {
+ struct {
+ u32 value;
+ struct kobj_attribute value_attr;
+ };
+ struct {
+ u32 read;
+ u32 set;
+ u32 clear;
+ struct kobj_attribute read_attr;
+ struct kobj_attribute set_attr;
+ struct kobj_attribute clear_attr;
+ };
+ };
+};
+
+static ssize_t bmc_misc_rmw_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct bmc_ctrl *ctrl;
+ unsigned int val;
+ int rc;
+
+ ctrl = container_of(attr, struct bmc_ctrl, value_attr);
+ rc = regmap_read(ctrl->map, ctrl->value, &val);
+ if (rc)
+ return rc;
+
+ val = (val & ctrl->mask) >> ctrl->shift;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t bmc_misc_rmw_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct bmc_ctrl *ctrl;
+ long val;
+ int rc;
+
+ rc = kstrtol(buf, 0, &val);
+ if (rc)
+ return rc;
+
+ ctrl = container_of(attr, struct bmc_ctrl, value_attr);
+ val <<= ctrl->shift;
+ if (val & ~ctrl->mask)
+ return -EINVAL;
+ rc = regmap_update_bits(ctrl->map, ctrl->value, ctrl->mask, val);
+
+ return rc < 0 ? rc : count;
+}
+
+static void bmc_misc_add_rmw_attrs(struct bmc_ctrl *ctrl,
+ struct attribute *attrs[6])
+{
+ sysfs_attr_init(&ctrl->attr.attr);
+ ctrl->value_attr.attr.name = "value";
+ ctrl->value_attr.attr.mode = 0664;
+ ctrl->value_attr.show = bmc_misc_rmw_show;
+ ctrl->value_attr.store = bmc_misc_rmw_store;
+ attrs[2] = &ctrl->value_attr.attr;
+ attrs[3] = NULL;
+}
+
+static int bmc_misc_init_rmw(struct bmc_ctrl *ctrl, struct device_node *node,
+ struct attribute *attrs[6])
+{
+ u32 val;
+ int rc;
+
+ rc = of_property_read_u32(node, "offset", &ctrl->value);
+ if (rc < 0)
+ return rc;
+
+ if (!of_property_read_u32(node, "default-value", &val)) {
+ val <<= ctrl->shift;
+ if (val & ~ctrl->mask)
+ return -EINVAL;
+ val &= ctrl->mask;
+ regmap_update_bits(ctrl->map, ctrl->value, ctrl->mask, val);
+ }
+
+ bmc_misc_add_rmw_attrs(ctrl, attrs);
+
+ return 0;
+}
+
+static ssize_t bmc_misc_sc_read_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct bmc_ctrl *ctrl;
+ unsigned int val;
+ int rc;
+
+ ctrl = container_of(attr, struct bmc_ctrl, read_attr);
+ rc = regmap_read(ctrl->map, ctrl->read, &val);
+ if (rc)
+ return rc;
+
+ val = (val & ctrl->mask) >> ctrl->shift;
+
+ return sprintf(buf, "%u\n", val);
+
+}
+
+static ssize_t bmc_misc_sc_set_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct bmc_ctrl *ctrl;
+ long val;
+ int rc;
+
+ rc = kstrtol(buf, 0, &val);
+ if (rc)
+ return rc;
+
+ ctrl = container_of(attr, struct bmc_ctrl, set_attr);
+ val <<= ctrl->shift;
+ if (val & ~ctrl->mask)
+ return -EINVAL;
+ val &= ctrl->mask;
+ rc = regmap_write(ctrl->map, ctrl->set, val);
+
+ return rc < 0 ? rc : count;
+}
+
+static ssize_t bmc_misc_sc_clear_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct bmc_ctrl *ctrl;
+ long val;
+ int rc;
+
+ rc = kstrtol(buf, 0, &val);
+ if (rc)
+ return rc;
+
+ ctrl = container_of(attr, struct bmc_ctrl, clear_attr);
+ val <<= ctrl->shift;
+ if (val & ~ctrl->mask)
+ return -EINVAL;
+ val &= ctrl->mask;
+ rc = regmap_write(ctrl->map, ctrl->clear, val);
+
+ return rc < 0 ? rc : count;
+}
+
+static void bmc_misc_add_sc_attrs(struct bmc_ctrl *ctrl,
+ struct attribute *attrs[6])
+{
+ sysfs_attr_init(&ctrl->read_attr.attr);
+ ctrl->read_attr.attr.name = "value";
+ ctrl->read_attr.attr.mode = 0444;
+ ctrl->read_attr.show = bmc_misc_sc_read_show;
+ attrs[2] = &ctrl->read_attr.attr;
+
+ sysfs_attr_init(&ctrl->set_attr.attr);
+ ctrl->set_attr.attr.name = "set";
+ ctrl->set_attr.attr.mode = 0200;
+ ctrl->set_attr.store = bmc_misc_sc_set_store;
+ attrs[3] = &ctrl->set_attr.attr;
+
+ sysfs_attr_init(&ctrl->clear_attr.attr);
+ ctrl->clear_attr.attr.name = "clear";
+ ctrl->clear_attr.attr.mode = 0200;
+ ctrl->clear_attr.store = bmc_misc_sc_clear_store;
+ attrs[4] = &ctrl->clear_attr.attr;
+
+ attrs[5] = NULL;
+}
+
+static int bmc_misc_init_sc(struct bmc_ctrl *ctrl, struct device_node *node,
+ struct attribute *attrs[6])
+{
+ int rc;
+
+ rc = of_property_read_u32_array(node, "offset", &ctrl->read, 3);
+ if (rc < 0)
+ return rc;
+
+ if (of_property_read_bool(node, "default-set"))
+ regmap_write(ctrl->map, ctrl->set, ctrl->mask);
+ else if (of_property_read_bool(node, "default-clear"))
+ regmap_write(ctrl->map, ctrl->clear, ctrl->mask);
+
+ bmc_misc_add_sc_attrs(ctrl, attrs);
+
+ return 0;
+}
+
+static ssize_t bmc_misc_label_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct bmc_ctrl *ctrl = container_of(attr, struct bmc_ctrl, label_attr);
+
+ return sprintf(buf, "%s\n", ctrl->label);
+}
+
+static ssize_t bmc_misc_mask_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct bmc_ctrl *ctrl = container_of(attr, struct bmc_ctrl, mask_attr);
+
+ return sprintf(buf, "0x%x\n", ctrl->mask >> ctrl->shift);
+}
+
+static int bmc_misc_init_dt(struct bmc_ctrl *ctrl, struct device_node *node,
+ struct attribute *attrs[6])
+{
+ int rc;
+
+ /* Example children:
+ *
+ * field at 80.6 {
+ * compatible = "bmc-misc-control";
+ * reg = <0x80>;
+ * bit-mask = <0x1>;
+ * bit-shift = <6>;
+ * label = "ilpc2ahb-disable";
+ * };
+ *
+ * field at 70.6 {
+ * compatible = "bmc-misc-control";
+ * // Write-1-set/Write-1-clear semantics
+ * set-clear;
+ * default-set;
+ * reg = <0x70 0x70 0x7c>
+ * bit-mask = <0x1>;
+ * bit-shift = <6>;
+ * label = "lpc-sio-decode-disable";
+ * };
+ *
+ * field at 50.0 {
+ * compatible = "bmc-misc-control";
+ * read-only;
+ * reg = <0x50>;
+ * bit-mask = <0xffffffff>;
+ * bit-shift = <0>;
+ * label = "vga-scratch-1";
+ * };
+ */
+ rc = of_property_read_u32(node, "mask", &ctrl->mask);
+ if (rc < 0)
+ return rc;
+
+ ctrl->shift = __ffs(ctrl->mask);
+ ctrl->ro = of_property_read_bool(node, "read-only");
+
+ rc = of_property_read_string(node, "label", &ctrl->label);
+ if (rc < 0)
+ return rc;
+
+ ctrl->label_attr.attr.name = "label";
+ ctrl->label_attr.attr.mode = 0444;
+ ctrl->label_attr.show = bmc_misc_label_show;
+ attrs[0] = &ctrl->label_attr.attr;
+
+ ctrl->mask_attr.attr.name = "mask";
+ ctrl->mask_attr.attr.mode = 0444;
+ ctrl->mask_attr.show = bmc_misc_mask_show;
+ attrs[1] = &ctrl->mask_attr.attr;
+
+ if (of_property_read_bool(node, "set-clear"))
+ return bmc_misc_init_sc(ctrl, node, attrs);
+
+ return bmc_misc_init_rmw(ctrl, node, attrs);
+}
+
+static struct class bmc_class = {
+ .name = "bmc",
+};
+
+static int bmc_misc_probe(struct platform_device *pdev)
+{
+ struct attribute *attrs[6];
+ struct attribute **attr;
+ struct bmc_ctrl *ctrl;
+ int rc;
+
+ ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
+ if (!ctrl)
+ return -ENOMEM;
+
+ ctrl->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
+
+ rc = bmc_misc_init_dt(ctrl, pdev->dev.of_node, attrs);
+ if (rc < 0)
+ return rc;
+
+ ctrl->dev = device_create(&bmc_class, &pdev->dev, 0, ctrl, "%s",
+ ctrl->label);
+ if (IS_ERR(ctrl->dev))
+ return PTR_ERR(ctrl->dev);
+
+ for (attr = &attrs[0]; *attr; attr++) {
+ rc = sysfs_create_file(&ctrl->dev->kobj, *attr);
+ if (rc < 0)
+ /* FIXME: Cleanup */
+ return rc;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id bmc_misc_match[] = {
+ { .compatible = "bmc-misc-ctrl" },
+ { },
+};
+
+static struct platform_driver bmc_misc = {
+ .driver = {
+ .name = "bmc-misc-ctrl",
+ .of_match_table = bmc_misc_match,
+ },
+ .probe = bmc_misc_probe,
+};
+
+static int bmc_misc_ctrl_init(void)
+{
+ int rc;
+
+ rc = class_register(&bmc_class);
+ if (rc < 0)
+ return rc;
+
+ return platform_driver_register(&bmc_misc);
+}
+module_init(bmc_misc_ctrl_init);
+
+static void bmc_misc_ctrl_exit(void)
+{
+ platform_driver_unregister(&bmc_misc);
+ class_unregister(&bmc_class);
+}
+module_exit(bmc_misc_ctrl_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrew Jeffery <andrew at aj.id.au>");
--
2.17.1
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