+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Xilinx Zynq MPSoC CSU Register Access
- *
- * Copyright (C) 2026 Advanced Micro Devices, Inc.
- *
- * Michal Simek <michal.simek@amd.com>
- * Ronak Jain <ronak.jain@amd.com>
- */
-
-#include <linux/firmware/xlnx-zynqmp.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-
-#include "zynqmp-csu-reg.h"
-
-/* Node ID for CSU module in firmware */
-#define CSU_NODE_ID 0
-
-/* Maximum number of CSU registers supported */
-#define MAX_CSU_REGS 50
-
-/* Size of register name returned by firmware (3 u32 words = 12 bytes) */
-#define CSU_REG_NAME_LEN 12
-
-/**
- * struct zynqmp_csu_reg - CSU register information
- * @id: Register index from firmware
- * @name: Register name
- * @attr: Device attribute for sysfs
- */
-struct zynqmp_csu_reg {
- u32 id;
- char name[CSU_REG_NAME_LEN];
- struct device_attribute attr;
-};
-
-/**
- * struct zynqmp_csu_data - Per-device CSU data
- * @csu_regs: Array of CSU registers
- * @csu_attr_group: Attribute group for sysfs
- */
-struct zynqmp_csu_data {
- struct zynqmp_csu_reg *csu_regs;
- struct attribute_group csu_attr_group;
-};
-
-/**
- * zynqmp_pm_get_node_count() - Get number of supported nodes via QUERY_DATA
- *
- * Return: Number of nodes on success, or negative error code
- */
-static int zynqmp_pm_get_node_count(void)
-{
- struct zynqmp_pm_query_data qdata = {0};
- u32 ret_payload[PAYLOAD_ARG_CNT];
- int ret;
-
- qdata.qid = PM_QID_GET_NODE_COUNT;
-
- ret = zynqmp_pm_query_data(qdata, ret_payload);
- if (ret)
- return ret;
-
- return ret_payload[1];
-}
-
-/**
- * zynqmp_pm_get_node_name() - Get node name via QUERY_DATA
- * @index: Register index
- * @name: Buffer to store register name
- *
- * Return: 0 on success, error code otherwise
- */
-static int zynqmp_pm_get_node_name(u32 index, char *name)
-{
- struct zynqmp_pm_query_data qdata = {0};
- u32 ret_payload[PAYLOAD_ARG_CNT];
- int ret;
-
- qdata.qid = PM_QID_GET_NODE_NAME;
- qdata.arg1 = index;
-
- ret = zynqmp_pm_query_data(qdata, ret_payload);
- if (ret)
- return ret;
-
- memcpy(name, &ret_payload[1], CSU_REG_NAME_LEN);
- name[CSU_REG_NAME_LEN - 1] = '\0';
-
- return 0;
-}
-
-/**
- * zynqmp_csu_reg_show() - Generic show function for all registers
- * @dev: Device pointer
- * @attr: Device attribute
- * @buf: Output buffer
- *
- * Return: Number of bytes written to buffer, or error code
- */
-static ssize_t zynqmp_csu_reg_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct zynqmp_csu_reg *reg;
- u32 value;
- int ret;
-
- /* Use container_of to get register directly */
- reg = container_of(attr, struct zynqmp_csu_reg, attr);
-
- ret = zynqmp_pm_sec_read_reg(CSU_NODE_ID, reg->id, &value);
- if (ret)
- return ret;
-
- return sysfs_emit(buf, "0x%08x\n", value);
-}
-
-/**
- * zynqmp_csu_reg_store() - Generic store function for writable registers
- * @dev: Device pointer
- * @attr: Device attribute
- * @buf: Input buffer
- * @count: Buffer size
- *
- * Format: "mask value" - both mask and value required
- * Example: echo "0xFFFFFFFF 0x12345678" > register
- *
- * Return: count on success, error code otherwise
- */
-static ssize_t zynqmp_csu_reg_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct zynqmp_csu_reg *reg;
- u32 mask, value;
- int ret;
-
- reg = container_of(attr, struct zynqmp_csu_reg, attr);
-
- if (sscanf(buf, "%x %x", &mask, &value) != 2)
- return -EINVAL;
-
- ret = zynqmp_pm_sec_mask_write_reg(CSU_NODE_ID, reg->id, mask, value);
- if (ret)
- return ret;
-
- return count;
-}
-
-/**
- * zynqmp_csu_discover_registers() - Discover CSU registers from firmware
- * @pdev: Platform device pointer
- *
- * This function uses PM_QUERY_DATA to discover all available CSU registers
- * and creates sysfs group under /sys/devices/platform/firmware:zynqmp-firmware/
- *
- * Return: 0 on success, error code otherwise
- */
-int zynqmp_csu_discover_registers(struct platform_device *pdev)
-{
- struct zynqmp_csu_data *csu_data;
- struct attribute **attrs;
- int count, ret, i;
-
- ret = zynqmp_pm_is_function_supported(PM_QUERY_DATA, PM_QID_GET_NODE_COUNT);
- if (ret) {
- dev_dbg(&pdev->dev, "CSU register discovery not supported by current firmware\n");
- return 0;
- }
-
- ret = zynqmp_pm_is_function_supported(PM_QUERY_DATA, PM_QID_GET_NODE_NAME);
- if (ret) {
- dev_dbg(&pdev->dev, "CSU register name query not supported by current firmware\n");
- return 0;
- }
-
- count = zynqmp_pm_get_node_count();
- if (count < 0)
- return count;
- if (count == 0) {
- dev_dbg(&pdev->dev, "No nodes available from firmware\n");
- return 0;
- }
-
- /* Validate count to prevent excessive memory allocation */
- if (count > MAX_CSU_REGS) {
- dev_err(&pdev->dev, "Register count %d exceeds maximum %d\n",
- count, MAX_CSU_REGS);
- return -EINVAL;
- }
-
- dev_dbg(&pdev->dev, "Discovered %d nodes from firmware\n", count);
-
- csu_data = devm_kzalloc(&pdev->dev, sizeof(*csu_data), GFP_KERNEL);
- if (!csu_data)
- return -ENOMEM;
-
- csu_data->csu_regs = devm_kcalloc(&pdev->dev, count, sizeof(*csu_data->csu_regs),
- GFP_KERNEL);
- if (!csu_data->csu_regs) {
- devm_kfree(&pdev->dev, csu_data);
- return -ENOMEM;
- }
-
- attrs = devm_kcalloc(&pdev->dev, count + 1, sizeof(*attrs), GFP_KERNEL);
- if (!attrs) {
- devm_kfree(&pdev->dev, csu_data->csu_regs);
- devm_kfree(&pdev->dev, csu_data);
- return -ENOMEM;
- }
-
- for (i = 0; i < count; i++) {
- struct zynqmp_csu_reg *reg = &csu_data->csu_regs[i];
- struct device_attribute *dev_attr = ®->attr;
-
- reg->id = i;
-
- ret = zynqmp_pm_get_node_name(i, reg->name);
- if (ret) {
- dev_warn(&pdev->dev, "Failed to get name for register %d\n", i);
- snprintf(reg->name, sizeof(reg->name), "csu_reg_%d", i);
- }
-
- /*
- * The firmware does not expose per-register access mode via
- * PM_QUERY_DATA today, so the kernel cannot tell read-only
- * registers from read-write ones at discovery time. Expose
- * every register as 0644 and rely on the firmware to reject
- * IOCTL_MASK_WRITE_REG on read-only registers; the error is
- * propagated back to userspace from the store callback.
- */
- sysfs_attr_init(&dev_attr->attr);
- dev_attr->attr.name = reg->name;
- dev_attr->attr.mode = 0644;
- dev_attr->show = zynqmp_csu_reg_show;
- dev_attr->store = zynqmp_csu_reg_store;
-
- attrs[i] = &dev_attr->attr;
-
- dev_dbg(&pdev->dev, "Register %d: id=%d name=%s\n", i, reg->id, reg->name);
- }
-
- csu_data->csu_attr_group.name = "csu_registers";
- csu_data->csu_attr_group.attrs = attrs;
-
- ret = devm_device_add_group(&pdev->dev, &csu_data->csu_attr_group);
- if (ret) {
- devm_kfree(&pdev->dev, attrs);
- devm_kfree(&pdev->dev, csu_data->csu_regs);
- devm_kfree(&pdev->dev, csu_data);
- }
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(zynqmp_csu_discover_registers);
projects / thirdparty / kernel / linux.git / commitdiff
