misc: xilinx_sdfec: Add stats & status ioctls

SD-FEC statistic data are:
- count of data interface errors (isr_err_count)
- count of Correctable ECC errors (cecc_count)
- count of Uncorrectable ECC errors (uecc_count)

Add support:
1. clear stats ioctl callback which clears collected
statistic data,
2. get stats ioctl callback which reads a collected
statistic data,
3. set default configuration ioctl callback,
4. start ioctl callback enables SD-FEC HW,
5. stop ioctl callback disables SD-FEC HW.

In a failed state driver enables the following ioctls:
- get status
- get statistics
- clear stats
- set default SD-FEC device configuration

Tested-by: Santhosh Dyavanapally <[e-mail]>
Tested by: Punnaiah Choudary Kalluri <[e-mail]>
Tested-by: Derek Kiernan <[e-mail]>
Tested-by: Dragan Cvetic <[e-mail]>
Signed-off-by: Derek Kiernan <[e-mail]>
Signed-off-by: Dragan Cvetic <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/xilinx_sdfec.c

···
  * @irq: IRQ number
  * @state_updated: indicates State updated by interrupt handler
  * @stats_updated: indicates Stats updated by interrupt handler
+ * @intr_enabled: indicates IRQ enabled
  *
  * This structure contains necessary state for SDFEC driver to operate
  */
···
 	int irq;
 	bool state_updated;
 	bool stats_updated;
+	bool intr_enabled;
 };
 
 static inline void xsdfec_regwrite(struct xsdfec_dev *xsdfec, u32 addr,
···
 		xsdfec->state = XSDFEC_STARTED;
 	else
 		xsdfec->state = XSDFEC_STOPPED;
+}
+
+static int xsdfec_get_status(struct xsdfec_dev *xsdfec, void __user *arg)
+{
+	struct xsdfec_status status;
+	int err;
+
+	spin_lock_irqsave(&xsdfec->error_data_lock, xsdfec->flags);
+	status.state = xsdfec->state;
+	xsdfec->state_updated = false;
+	spin_unlock_irqrestore(&xsdfec->error_data_lock, xsdfec->flags);
+	status.activity = (xsdfec_regread(xsdfec, XSDFEC_ACTIVE_ADDR) &
+			   XSDFEC_IS_ACTIVITY_SET);
+
+	err = copy_to_user(arg, &status, sizeof(status));
+	if (err)
+		err = -EFAULT;
+
+	return err;
 }
 
 static int xsdfec_get_config(struct xsdfec_dev *xsdfec, void __user *arg)
···
 	return 0;
 }
 
+static int xsdfec_start(struct xsdfec_dev *xsdfec)
+{
+	u32 regread;
+
+	regread = xsdfec_regread(xsdfec, XSDFEC_FEC_CODE_ADDR);
+	regread &= 0x1;
+	if (regread != xsdfec->config.code) {
+		dev_dbg(xsdfec->dev,
+			"%s SDFEC HW code does not match driver code, reg %d, code %d",
+			__func__, regread, xsdfec->config.code);
+		return -EINVAL;
+	}
+
+	/* Set AXIS enable */
+	xsdfec_regwrite(xsdfec, XSDFEC_AXIS_ENABLE_ADDR,
+			XSDFEC_AXIS_ENABLE_MASK);
+	/* Done */
+	xsdfec->state = XSDFEC_STARTED;
+	return 0;
+}
+
+static int xsdfec_stop(struct xsdfec_dev *xsdfec)
+{
+	u32 regread;
+
+	if (xsdfec->state != XSDFEC_STARTED)
+		dev_dbg(xsdfec->dev, "Device not started correctly");
+	/* Disable AXIS_ENABLE Input interfaces only */
+	regread = xsdfec_regread(xsdfec, XSDFEC_AXIS_ENABLE_ADDR);
+	regread &= (~XSDFEC_AXIS_IN_ENABLE_MASK);
+	xsdfec_regwrite(xsdfec, XSDFEC_AXIS_ENABLE_ADDR, regread);
+	/* Stop */
+	xsdfec->state = XSDFEC_STOPPED;
+	return 0;
+}
+
+static int xsdfec_clear_stats(struct xsdfec_dev *xsdfec)
+{
+	spin_lock_irqsave(&xsdfec->error_data_lock, xsdfec->flags);
+	xsdfec->isr_err_count = 0;
+	xsdfec->uecc_count = 0;
+	xsdfec->cecc_count = 0;
+	spin_unlock_irqrestore(&xsdfec->error_data_lock, xsdfec->flags);
+
+	return 0;
+}
+
+static int xsdfec_get_stats(struct xsdfec_dev *xsdfec, void __user *arg)
+{
+	int err;
+	struct xsdfec_stats user_stats;
+
+	spin_lock_irqsave(&xsdfec->error_data_lock, xsdfec->flags);
+	user_stats.isr_err_count = xsdfec->isr_err_count;
+	user_stats.cecc_count = xsdfec->cecc_count;
+	user_stats.uecc_count = xsdfec->uecc_count;
+	xsdfec->stats_updated = false;
+	spin_unlock_irqrestore(&xsdfec->error_data_lock, xsdfec->flags);
+
+	err = copy_to_user(arg, &user_stats, sizeof(user_stats));
+	if (err)
+		err = -EFAULT;
+
+	return err;
+}
+
+static int xsdfec_set_default_config(struct xsdfec_dev *xsdfec)
+{
+	/* Ensure registers are aligned with core configuration */
+	xsdfec_regwrite(xsdfec, XSDFEC_FEC_CODE_ADDR, xsdfec->config.code);
+	xsdfec_cfg_axi_streams(xsdfec);
+	update_config_from_hw(xsdfec);
+
+	return 0;
+}
+
 static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd,
 			     unsigned long data)
 {
···
 
 	xsdfec = container_of(fptr->private_data, struct xsdfec_dev, miscdev);
 
+	/* In failed state allow only reset and get status IOCTLs */
+	if (xsdfec->state == XSDFEC_NEEDS_RESET &&
+	    (cmd != XSDFEC_SET_DEFAULT_CONFIG && cmd != XSDFEC_GET_STATUS &&
+	     cmd != XSDFEC_GET_STATS && cmd != XSDFEC_CLEAR_STATS)) {
+		return -EPERM;
+	}
+
+	if (_IOC_TYPE(cmd) != XSDFEC_MAGIC)
+		return -ENOTTY;
+
 	/* check if ioctl argument is present and valid */
 	if (_IOC_DIR(cmd) != _IOC_NONE) {
 		arg = (void __user *)data;
···
 	}
 
 	switch (cmd) {
+	case XSDFEC_START_DEV:
+		rval = xsdfec_start(xsdfec);
+		break;
+	case XSDFEC_STOP_DEV:
+		rval = xsdfec_stop(xsdfec);
+		break;
+	case XSDFEC_CLEAR_STATS:
+		rval = xsdfec_clear_stats(xsdfec);
+		break;
+	case XSDFEC_GET_STATS:
+		rval = xsdfec_get_stats(xsdfec, arg);
+		break;
+	case XSDFEC_GET_STATUS:
+		rval = xsdfec_get_status(xsdfec, arg);
+		break;
 	case XSDFEC_GET_CONFIG:
 		rval = xsdfec_get_config(xsdfec, arg);
+		break;
+	case XSDFEC_SET_DEFAULT_CONFIG:
+		rval = xsdfec_set_default_config(xsdfec);
 		break;
 	case XSDFEC_SET_IRQ:
 		rval = xsdfec_set_irq(xsdfec, arg);

include/uapi/misc/xilinx_sdfec.h

···
 };
 
 /**
+ * struct xsdfec_stats - Stats retrived by ioctl XSDFEC_GET_STATS. Used
+ *			 to buffer atomic_t variables from struct
+ *			 xsdfec_dev. Counts are accumulated until
+ *			 the user clears them.
+ * @isr_err_count: Count of ISR errors
+ * @cecc_count: Count of Correctable ECC errors (SBE)
+ * @uecc_count: Count of Uncorrectable ECC errors (MBE)
+ */
+struct xsdfec_stats {
+	__u32 isr_err_count;
+	__u32 cecc_count;
+	__u32 uecc_count;
+};
+
+/**
  * struct xsdfec_ldpc_param_table_sizes - Used to store sizes of SD-FEC table
  *					  entries for an individual LPDC code
  *					  parameter.
···
  * XSDFEC IOCTL List
  */
 #define XSDFEC_MAGIC 'f'
+/**
+ * DOC: XSDFEC_START_DEV
+ *
+ * @Description
+ *
+ * ioctl to start SD-FEC core
+ *
+ * This fails if the XSDFEC_SET_ORDER ioctl has not been previously called
+ */
+#define XSDFEC_START_DEV _IO(XSDFEC_MAGIC, 0)
+/**
+ * DOC: XSDFEC_STOP_DEV
+ *
+ * @Description
+ *
+ * ioctl to stop the SD-FEC core
+ */
+#define XSDFEC_STOP_DEV _IO(XSDFEC_MAGIC, 1)
+/**
+ * DOC: XSDFEC_GET_STATUS
+ *
+ * @Description
+ *
+ * ioctl that returns status of SD-FEC core
+ */
+#define XSDFEC_GET_STATUS _IOR(XSDFEC_MAGIC, 2, struct xsdfec_status)
 /**
  * DOC: XSDFEC_SET_IRQ
  * @Parameters
···
  * ioctl that determines if SD-FEC is processing data
  */
 #define XSDFEC_IS_ACTIVE _IOR(XSDFEC_MAGIC, 10, bool)
+/**
+ * DOC: XSDFEC_CLEAR_STATS
+ *
+ * @Description
+ *
+ * ioctl that clears error stats collected during interrupts
+ */
+#define XSDFEC_CLEAR_STATS _IO(XSDFEC_MAGIC, 11)
+/**
+ * DOC: XSDFEC_GET_STATS
+ * @Parameters
+ *
+ * @struct xsdfec_stats *
+ *	Pointer to the &struct xsdfec_stats that will contain the updated stats
+ *	values
+ *
+ * @Description
+ *
+ * ioctl that returns SD-FEC core stats
+ *
+ * This can only be used when the driver is in the XSDFEC_STOPPED state
+ */
+#define XSDFEC_GET_STATS _IOR(XSDFEC_MAGIC, 12, struct xsdfec_stats)
+/**
+ * DOC: XSDFEC_SET_DEFAULT_CONFIG
+ *
+ * @Description
+ *
+ * ioctl that returns SD-FEC core to default config, use after a reset
+ *
+ * This can only be used when the driver is in the XSDFEC_STOPPED state
+ */
+#define XSDFEC_SET_DEFAULT_CONFIG _IO(XSDFEC_MAGIC, 13)
+
 #endif /* __XILINX_SDFEC_H__ */