Re: [PATCH 1/5] firmware: xilinx: Adds new eemi call for reg access

Michal Simek
2019-12-18T14:17:07Z

On 18. 12. 19 15:10, Michal Simek wrote:
> On 05. 12. 19 0:29, Jolly Shah wrote:
>> From: Rajan Vaja <rajan.vaja@xilinx.com>
>>
>> This patch adds new EEMI call which is used for CSU/PMU register
>> access from linux.
>>
>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
>> Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
>> Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
>> ---
>> drivers/firmware/xilinx/zynqmp.c | 183 +++++++++++++++++++++++++++++++++++
>> include/linux/firmware/xlnx-zynqmp.h | 9 ++
>> 2 files changed, 192 insertions(+)
>>
>> diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
>> index fd3d837..56431ad 100644
>> --- a/drivers/firmware/xilinx/zynqmp.c
>> +++ b/drivers/firmware/xilinx/zynqmp.c
>> @@ -24,6 +24,8 @@
>> #include <linux/firmware/xlnx-zynqmp.h>
>> #include "zynqmp-debug.h"
>>
>> +static unsigned long register_address;
>> +
>> static const struct zynqmp_eemi_ops *eemi_ops_tbl;
>>
>> static const struct mfd_cell firmware_devs[] = {
>> @@ -664,6 +666,26 @@ static int zynqmp_pm_set_requirement(const u32 node, const u32 capabilities,
>> qos, ack, NULL);
>> }
>>
>> +/**
>> + * zynqmp_pm_config_reg_access - PM Config API for Config register access
>> + * @register_access_id: ID of the requested REGISTER_ACCESS
>> + * @address: Address of the register to be accessed
>> + * @mask: Mask to be written to the register
>> + * @value: Value to be written to the register
>> + * @out: Returned output value
>> + *
>> + * This function calls REGISTER_ACCESS to configure CSU/PMU registers.
>> + *
>> + * Return: Returns status, either success or error+reason
>> + */
>> +
>> +static int zynqmp_pm_config_reg_access(u32 register_access_id, u32 address,
>> + u32 mask, u32 value, u32 *out)
>> +{
>> + return zynqmp_pm_invoke_fn(PM_REGISTER_ACCESS, register_access_id,
>> + address, mask, value, out);
>> +}
>> +
>> static const struct zynqmp_eemi_ops eemi_ops = {
>> .get_api_version = zynqmp_pm_get_api_version,
>> .get_chipid = zynqmp_pm_get_chipid,
>> @@ -687,6 +709,7 @@ static const struct zynqmp_eemi_ops eemi_ops = {
>> .set_requirement = zynqmp_pm_set_requirement,
>> .fpga_load = zynqmp_pm_fpga_load,
>> .fpga_get_status = zynqmp_pm_fpga_get_status,
>> + .register_access = zynqmp_pm_config_reg_access,
>> };
>>
>> /**
>> @@ -704,6 +727,160 @@ const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
>> }
>> EXPORT_SYMBOL_GPL(zynqmp_pm_get_eemi_ops);
>>
>> +/**
>> + * config_reg_store - Write config_reg sysfs attribute
>> + * @kobj: Kobject structure
>> + * @attr: Kobject attribute structure
>> + * @buf: User entered health_status attribute string
>> + * @count: Buffer size
>> + *
>> + * User-space interface for setting the config register.
>> + *
>> + * To write any CSU/PMU register
>> + * echo <mask> <values> > /sys/firmware/zynqmp/config_reg
>> + * Usage:
>> + * echo 0x345AB234 0xFFFFFFFF 0x1234ABCD > /sys/firmware/zynqmp/config_reg
>> + *
>> + * To Read any CSU/PMU register, write address to the variable like below
>> + * echo > /sys/firmware/zynqmp/config_reg
>> + *
>> + * Return: count argument if request succeeds, the corresponding error
>> + * code otherwise
>> + */
>> +static ssize_t config_reg_store(struct kobject *kobj,
>> + struct kobj_attribute *attr,
>> + const char *buf, size_t count)
>> +{
>> + char *kern_buff, *inbuf, *tok;
>> + unsigned long address, value, mask;
>> + int ret;
>> +
>> + kern_buff = kzalloc(count, GFP_KERNEL);
>> + if (!kern_buff)
>> + return -ENOMEM;
>> +
>> + ret = strlcpy(kern_buff, buf, count);
>> + if (ret < 0) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>
> Greg: What's the recommended way how to parse parameters via sysfs?
> I see that kstrndup is used for cloning buffer instead of kzalloc
> followed by strchr and sscanf.
>
>
>> +
>> + inbuf = kern_buff;
>> +
>> + /* Read the addess */
>
> typo here.
>
>> + tok = strsep(&inbuf, " ");
>> + if (!tok) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>> + ret = kstrtol(tok, 16, &address);
>> + if (ret) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>> + /* Read the write value */
>> + tok = strsep(&inbuf, " ");
>> + /*
>> + * If parameter provided is only address, then its a read operation.
>> + * Store the address in a global variable and retrieve whenever
>> + * required.
>> + */
>> + if (!tok) {
>> + register_address = address;
>> + goto err;
>> + }
>> + register_address = address;
>> +
>> + ret = kstrtol(tok, 16, &mask);
>> + if (ret) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>> + tok = strsep(&inbuf, " ");
>> + if (!tok) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>> + ret = kstrtol(tok, 16, &value);
>> + if (!tok) {
>> + ret = -EFAULT;
>> + goto err;
>> + }
>> + ret = zynqmp_pm_config_reg_access(CONFIG_REG_WRITE, address,
>> + mask, value, NULL);
>> + if (ret)
>> + pr_err("unable to write value to %lx\n", value);
>> +err:
>> + kfree(kern_buff);
>> + if (ret)
>> + return ret;
>> + return count;
>> +}
>> +
>> +/**
>> + * config_reg_show - Read config_reg sysfs attribute
>> + * @kobj: Kobject structure
>> + * @attr: Kobject attribute structure
>> + * @buf: User entered health_status attribute string
>> + *
>> + * User-space interface for getting the config register.
>> + *
>> + * To Read any CSU/PMU register, write address to the variable like below
>> + * echo > /sys/firmware/zynqmp/config_reg
>> + *
>> + * Then Read the address using below command
>> + * cat /sys/firmware/zynqmp/config_reg
>> + *
>> + * Return: number of chars written to buf.
>> + */
>> +static ssize_t config_reg_show(struct kobject *kobj,
>> + struct kobj_attribute *attr,
>> + char *buf)
>> +{
>> + int ret;
>> + u32 ret_payload[PAYLOAD_ARG_CNT];
>> +
>> + ret = zynqmp_pm_config_reg_access(CONFIG_REG_READ, register_address,
>> + 0, 0, ret_payload);
>> + if (ret)
>> + return ret;
>> +
>> + return sprintf(buf, "0x%x\n", ret_payload[1]);
>> +}
>> +
>> +static struct kobj_attribute zynqmp_attr_config_reg =
>> + __ATTR_RW(config_reg);
>
>
> use DEVICE_ATTR_RW() instead
>
>> +
>> +static struct attribute *attrs[] = {
>> + &zynqmp_attr_config_reg.attr,
>> + NULL,
>> +};
>
>> +
>> +static const struct attribute_group attr_group = {
>> + .attrs = attrs,
>> + NULL,
>> +};
>
> ATTRIBUTE_GROUPS instead.
>
>> +
>> +static int zynqmp_pm_sysfs_init(void)
>> +{
>> + struct kobject *zynqmp_kobj;
>> + int ret;
>> +
>> + zynqmp_kobj = kobject_create_and_add("zynqmp", firmware_kobj);
>> + if (!zynqmp_kobj) {
>> + pr_err("zynqmp: Firmware kobj add failed.\n");
>> + return -ENOMEM;
>> + }
>> +
>> + ret = sysfs_create_group(zynqmp_kobj, &attr_group);
>> + if (ret) {
>> + pr_err("%s() sysfs creation fail with error %d\n",
>> + __func__, ret);
>
> if you fail here you should free kobject_put(zynqmp_kobj);
>
>
>> + }
>> +
>> + return ret;
>> +}
>> +
>> static int zynqmp_firmware_probe(struct platform_device *pdev)
>> {
>> struct device *dev = &pdev->dev;
>> @@ -748,6 +925,12 @@ static int zynqmp_firmware_probe(struct platform_device *pdev)
>> /* Assign eemi_ops_table */
>> eemi_ops_tbl = &eemi_ops;
>>
>> + ret = zynqmp_pm_sysfs_init();
>> + if (ret) {
>> + pr_err("%s() sysfs init fail with error %d\n", __func__, ret);
>> + return ret;
>> + }
>> +
>> zynqmp_pm_api_debugfs_init();
>>
>> ret = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, firmware_devs,
>> diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
>> index df366f1..55561d0 100644
>> --- a/include/linux/firmware/xlnx-zynqmp.h
>> +++ b/include/linux/firmware/xlnx-zynqmp.h
>> @@ -77,6 +77,8 @@ enum pm_api_id {
>> PM_CLOCK_GETRATE,
>> PM_CLOCK_SETPARENT,
>> PM_CLOCK_GETPARENT,
>> + /* PM_REGISTER_ACCESS API */
>> + PM_REGISTER_ACCESS = 52,
>> };
>>
>> /* PMU-FW return status codes */
>> @@ -261,6 +263,11 @@ enum tap_delay_type {
>> PM_TAPDELAY_OUTPUT,
>> };
>>
>> +enum pm_register_access_id {
>> + CONFIG_REG_WRITE,
>> + CONFIG_REG_READ,
>> +};
>> +
>> /**
>> * struct zynqmp_pm_query_data - PM query data
>> * @qid: query ID
>> @@ -305,6 +312,8 @@ struct zynqmp_eemi_ops {
>> const u32 capabilities,
>> const u32 qos,
>> const enum zynqmp_pm_request_ack ack);
>> + int (*register_access)(u32 register_access_id, u32 address,
>> + u32 mask, u32 value, u32 *out);
>> };
>>
>> int zynqmp_pm_invoke_fn(u32 pm_api_id, u32 arg0, u32 arg1,
>>
>

One more thing. I am missing sysfs description for these entries.
You are creating this file in 2/5 but files introduced here are not
cover there.

Thanks,
Michal