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Subject[PATCH 06/10] platform/x86: ISST: Add Intel Speed Select mailbox interface via PCI
Date
Add an IOCTL to send mailbox commands to PUNIT using PUNIT PCI device.
A limited set of mailbox commands can be sent to PUNIT.

This MMIO interface is used by the intel-speed-select tool under
tools/x86/power to enumerate and control Intel Speed Select features.
The MBOX commands ids and semantics of the message can be checked from
the source code of the tool.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
.../x86/intel_speed_select_if/Makefile | 1 +
.../intel_speed_select_if/isst_if_common.c | 85 ++++++++
.../intel_speed_select_if/isst_if_common.h | 3 +
.../intel_speed_select_if/isst_if_mbox_pci.c | 199 ++++++++++++++++++
include/uapi/linux/isst_if.h | 38 ++++
5 files changed, 326 insertions(+)
create mode 100644 drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c

diff --git a/drivers/platform/x86/intel_speed_select_if/Makefile b/drivers/platform/x86/intel_speed_select_if/Makefile
index 7e94919208d3..8dec8c858649 100644
--- a/drivers/platform/x86/intel_speed_select_if/Makefile
+++ b/drivers/platform/x86/intel_speed_select_if/Makefile
@@ -6,3 +6,4 @@

obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_common.o
obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_mmio.o
+obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_mbox_pci.o
diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
index 3f96a3925bc6..391fc3f12161 100644
--- a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
@@ -25,6 +25,86 @@

static struct isst_if_cmd_cb punit_callbacks[ISST_IF_DEV_MAX];

+struct isst_valid_cmd_ranges {
+ u16 cmd;
+ u16 sub_cmd_beg;
+ u16 sub_cmd_end;
+};
+
+struct isst_cmd_set_req_type {
+ u16 cmd;
+ u16 sub_cmd;
+ u16 param;
+};
+
+static const struct isst_valid_cmd_ranges isst_valid_cmds[] = {
+ {0xD0, 0x00, 0x03},
+ {0x7F, 0x00, 0x0B},
+ {0x7F, 0x10, 0x12},
+ {0x7F, 0x20, 0x23},
+};
+
+static const struct isst_cmd_set_req_type isst_cmd_set_reqs[] = {
+ {0xD0, 0x00, 0x08},
+ {0xD0, 0x01, 0x08},
+ {0xD0, 0x02, 0x08},
+ {0xD0, 0x03, 0x08},
+ {0x7F, 0x02, 0x00},
+ {0x7F, 0x08, 0x00},
+};
+
+/**
+ * isst_if_mbox_cmd_invalid() - Check invalid mailbox commands
+ * @cmd: Pointer to the command structure to verify.
+ *
+ * Invalid command to PUNIT to may result in instability of the platform.
+ * This function has a whitelist of commands, which are allowed.
+ *
+ * Return: Return true if the command is invalid, else false.
+ */
+bool isst_if_mbox_cmd_invalid(struct isst_if_mbox_cmd *cmd)
+{
+ int i;
+
+ if (cmd->logical_cpu >= nr_cpu_ids)
+ return true;
+
+ for (i = 0; i < ARRAY_SIZE(isst_valid_cmds); ++i) {
+ if (cmd->command == isst_valid_cmds[i].cmd &&
+ (cmd->sub_command >= isst_valid_cmds[i].sub_cmd_beg &&
+ cmd->sub_command <= isst_valid_cmds[i].sub_cmd_end)) {
+ return false;
+ }
+ }
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(isst_if_mbox_cmd_invalid);
+
+/**
+ * isst_if_mbox_cmd_set_req() - Check mailbox command is a set request
+ * @cmd: Pointer to the command structure to verify.
+ *
+ * Check if the given mail box level is set request and not a get request.
+ *
+ * Return: Return true if the command is set_req, else false.
+ */
+bool isst_if_mbox_cmd_set_req(struct isst_if_mbox_cmd *cmd)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(isst_cmd_set_reqs); ++i) {
+ if (cmd->command == isst_cmd_set_reqs[i].cmd &&
+ cmd->sub_command == isst_cmd_set_reqs[i].sub_cmd &&
+ cmd->parameter == isst_cmd_set_reqs[i].param) {
+ return true;
+ }
+ }
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(isst_if_mbox_cmd_set_req);
+
static int isst_if_get_platform_info(void __user *argp)
{
struct isst_if_platform_info info;
@@ -224,6 +304,11 @@ static long isst_if_def_ioctl(struct file *file, unsigned int cmd,
if (cb->registered)
ret = isst_if_exec_multi_cmd(argp, cb);
break;
+ case ISST_IF_MBOX_COMMAND:
+ cb = &punit_callbacks[ISST_IF_DEV_MBOX];
+ if (cb->registered)
+ ret = isst_if_exec_multi_cmd(argp, cb);
+ break;
default:
break;
}
diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_common.h b/drivers/platform/x86/intel_speed_select_if/isst_if_common.h
index cdc7d019748a..7c0f71221da7 100644
--- a/drivers/platform/x86/intel_speed_select_if/isst_if_common.h
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_common.h
@@ -11,6 +11,7 @@
#define __ISST_IF_COMMON_H

#define INTEL_RAPL_PRIO_DEVID_0 0x3451
+#define INTEL_CFG_MBOX_DEVID_0 0x3459

/*
* Validate maximum commands in a single request.
@@ -60,4 +61,6 @@ struct isst_if_cmd_cb {
int isst_if_cdev_register(int type, struct isst_if_cmd_cb *cb);
void isst_if_cdev_unregister(int type);
struct pci_dev *isst_if_get_pci_dev(int cpu, int bus, int dev, int fn);
+bool isst_if_mbox_cmd_set_req(struct isst_if_mbox_cmd *mbox_cmd);
+bool isst_if_mbox_cmd_invalid(struct isst_if_mbox_cmd *cmd);
#endif
diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c b/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c
new file mode 100644
index 000000000000..f03e79afd3f1
--- /dev/null
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Speed Select Interface: Mbox via PCI Interface
+ * Copyright (c) 2019, Intel Corporation.
+ * All rights reserved.
+ *
+ * Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
+ */
+
+#include <linux/cpufeature.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/sched/signal.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/isst_if.h>
+
+#include "isst_if_common.h"
+
+#define PUNIT_MAILBOX_DATA 0xA0
+#define PUNIT_MAILBOX_INTERFACE 0xA4
+#define PUNIT_MAILBOX_BUSY_BIT 31
+
+/*
+ * Commands has variable amount of processing time. Most of the commands will
+ * be done in 0-3 tries, but some takes up to 50.
+ * The real processing time was observed as 25us for the most of the commands
+ * at 2GHz. It is possible to optimize this count taking samples on customer
+ * systems.
+ */
+#define OS_MAILBOX_RETRY_COUNT 50
+
+struct isst_if_device {
+ struct mutex mutex;
+};
+
+static int isst_if_mbox_cmd(struct pci_dev *pdev,
+ struct isst_if_mbox_cmd *mbox_cmd)
+{
+ u32 retries, data;
+ int ret;
+
+ /* Poll for rb bit == 0 */
+ retries = OS_MAILBOX_RETRY_COUNT;
+ do {
+ ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_INTERFACE,
+ &data);
+ if (ret)
+ return ret;
+
+ if (data & BIT_ULL(PUNIT_MAILBOX_BUSY_BIT)) {
+ ret = -EBUSY;
+ continue;
+ }
+ ret = 0;
+ break;
+ } while (--retries);
+
+ if (ret)
+ return ret;
+
+ /* Write DATA register */
+ ret = pci_write_config_dword(pdev, PUNIT_MAILBOX_DATA,
+ mbox_cmd->req_data);
+ if (ret)
+ return ret;
+
+ /* Write command register */
+ data = BIT_ULL(PUNIT_MAILBOX_BUSY_BIT) |
+ (mbox_cmd->parameter & GENMASK_ULL(13, 0)) << 16 |
+ (mbox_cmd->sub_command << 8) |
+ mbox_cmd->command;
+
+ ret = pci_write_config_dword(pdev, PUNIT_MAILBOX_INTERFACE, data);
+ if (ret)
+ return ret;
+
+ /* Poll for rb bit == 0 */
+ retries = OS_MAILBOX_RETRY_COUNT;
+ do {
+ ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_INTERFACE,
+ &data);
+ if (ret)
+ return ret;
+
+ if (data & BIT_ULL(PUNIT_MAILBOX_BUSY_BIT)) {
+ ret = -EBUSY;
+ continue;
+ }
+
+ if (data & 0xff)
+ return -ENXIO;
+
+ ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_DATA, &data);
+ if (ret)
+ return ret;
+
+ mbox_cmd->resp_data = data;
+ ret = 0;
+ break;
+ } while (--retries);
+
+ return ret;
+}
+
+static long isst_if_mbox_proc_cmd(u8 *cmd_ptr, int *write_only, int resume)
+{
+ struct isst_if_mbox_cmd *mbox_cmd;
+ struct isst_if_device *punit_dev;
+ struct pci_dev *pdev;
+ int ret;
+
+ mbox_cmd = (struct isst_if_mbox_cmd *)cmd_ptr;
+
+ if (isst_if_mbox_cmd_invalid(mbox_cmd))
+ return -EINVAL;
+
+ if (isst_if_mbox_cmd_set_req(mbox_cmd) && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ pdev = isst_if_get_pci_dev(mbox_cmd->logical_cpu, 1, 30, 1);
+ if (!pdev)
+ return -EINVAL;
+
+ punit_dev = pci_get_drvdata(pdev);
+ if (!punit_dev)
+ return -EINVAL;
+
+ /*
+ * Basically we are allowing one complete mailbox transaction on
+ * a mapped PCI device at a time.
+ */
+ mutex_lock(&punit_dev->mutex);
+ ret = isst_if_mbox_cmd(pdev, mbox_cmd);
+ mutex_unlock(&punit_dev->mutex);
+ if (ret)
+ return ret;
+
+ *write_only = 0;
+
+ return 0;
+}
+
+static const struct pci_device_id isst_if_mbox_ids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL, INTEL_CFG_MBOX_DEVID_0)},
+ { 0 },
+};
+MODULE_DEVICE_TABLE(pci, isst_if_mbox_ids);
+
+static int isst_if_mbox_probe(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ struct isst_if_device *punit_dev;
+ struct isst_if_cmd_cb cb;
+ int ret;
+
+ punit_dev = devm_kzalloc(&pdev->dev, sizeof(*punit_dev), GFP_KERNEL);
+ if (!punit_dev)
+ return -ENOMEM;
+
+ ret = pcim_enable_device(pdev);
+ if (ret)
+ return ret;
+
+ mutex_init(&punit_dev->mutex);
+ pci_set_drvdata(pdev, punit_dev);
+
+ memset(&cb, 0, sizeof(cb));
+ cb.cmd_size = sizeof(struct isst_if_mbox_cmd);
+ cb.offset = offsetof(struct isst_if_mbox_cmds, mbox_cmd);
+ cb.cmd_callback = isst_if_mbox_proc_cmd;
+ cb.owner = THIS_MODULE;
+ ret = isst_if_cdev_register(ISST_IF_DEV_MBOX, &cb);
+
+ if (ret)
+ mutex_destroy(&punit_dev->mutex);
+
+ return ret;
+}
+
+static void isst_if_mbox_remove(struct pci_dev *pdev)
+{
+ struct isst_if_device *punit_dev;
+
+ punit_dev = pci_get_drvdata(pdev);
+ isst_if_cdev_unregister(ISST_IF_DEV_MBOX);
+ mutex_destroy(&punit_dev->mutex);
+}
+
+static struct pci_driver isst_if_pci_driver = {
+ .name = "isst_if_mbox_pci",
+ .id_table = isst_if_mbox_ids,
+ .probe = isst_if_mbox_probe,
+ .remove = isst_if_mbox_remove,
+};
+
+module_pci_driver(isst_if_pci_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel speed select interface pci mailbox driver");
diff --git a/include/uapi/linux/isst_if.h b/include/uapi/linux/isst_if.h
index fe2492ade078..e4b1c2ec3279 100644
--- a/include/uapi/linux/isst_if.h
+++ b/include/uapi/linux/isst_if.h
@@ -95,8 +95,46 @@ struct isst_if_io_regs {
struct isst_if_io_reg io_reg[1];
};

+/**
+ * struct isst_if_mbox_cmd - Structure to define mail box command
+ * @logical_cpu: Logical CPU number to get target PCI device
+ * @parameter: Mailbox parameter value
+ * @req_data: Request data for the mailbox
+ * @resp_data: Response data for mailbox command response
+ * @command: Mailbox command value
+ * @sub_command: Mailbox sub command value
+ * @reserved: Unused, set to 0
+ *
+ * Structure to specify mailbox command to be sent to PUNIT.
+ */
+struct isst_if_mbox_cmd {
+ __u32 logical_cpu;
+ __u32 parameter;
+ __u32 req_data;
+ __u32 resp_data;
+ __u16 command;
+ __u16 sub_command;
+ __u32 reserved;
+};
+
+/**
+ * struct isst_if_mbox_cmds - structure for mailbox commands
+ * @cmd_count: Number of mailbox commands in mbox_cmd[]
+ * @mbox_cmd[]: Holds one or more mbox commands
+ *
+ * This structure used with ioctl ISST_IF_MBOX_COMMAND to send
+ * one or more mailbox commands to PUNIT. Here IOCTL return value
+ * indicates number of commands sent or error number if no commands have
+ * been sent.
+ */
+struct isst_if_mbox_cmds {
+ __u32 cmd_count;
+ struct isst_if_mbox_cmd mbox_cmd[1];
+};
+
#define ISST_IF_MAGIC 0xFE
#define ISST_IF_GET_PLATFORM_INFO _IOR(ISST_IF_MAGIC, 0, struct isst_if_platform_info *)
#define ISST_IF_GET_PHY_ID _IOWR(ISST_IF_MAGIC, 1, struct isst_if_cpu_map *)
#define ISST_IF_IO_CMD _IOW(ISST_IF_MAGIC, 2, struct isst_if_io_regs *)
+#define ISST_IF_MBOX_COMMAND _IOWR(ISST_IF_MAGIC, 3, struct isst_if_mbox_cmds *)
#endif
--
2.17.2
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