/*
 * sfpdiag.c: Implements SFF-8472 optics diagnostics.
 *
 * Aurelien Guillaume <aurelien@iwi.me> (C) 2012
 *   This implementation is loosely based on DOM patches
 *   from Robert Olsson <robert@herjulf.se> (C) 2009
 *   and SFF-8472 specs (ftp://ftp.seagate.com/pub/sff/SFF-8472.PDF)
 *   by SFF Committee.
 */

#include <stdio.h>
#include <math.h>
#include <arpa/inet.h>
#include "internal.h"
#include "sff-common.h"

/* Offsets in decimal, for direct comparison with the SFF specs */

/* A0-based EEPROM offsets for DOM support checks */
#define SFF_A0_DOM                        92
#define SFF_A0_OPTIONS                    93
#define SFF_A0_COMP                       94

/* EEPROM bit values for various registers */
#define SFF_A0_DOM_EXTCAL                 (1 << 4)
#define SFF_A0_DOM_INTCAL                 (1 << 5)
#define SFF_A0_DOM_IMPL                   (1 << 6)
#define SFF_A0_DOM_PWRT                   (1 << 3)

#define SFF_A0_OPTIONS_AW                 (1 << 7)

/*
 * See ethtool.c comments about SFF-8472, this is the offset
 * at which the A2 page is in the EEPROM blob returned by the
 * kernel.
 */
#define SFF_A2_BASE                       0x100

/* A2-based offsets for DOM */
#define SFF_A2_TEMP                       96
#define SFF_A2_TEMP_HALRM                 0
#define SFF_A2_TEMP_LALRM                 2
#define SFF_A2_TEMP_HWARN                 4
#define SFF_A2_TEMP_LWARN                 6

#define SFF_A2_VCC                        98
#define SFF_A2_VCC_HALRM                  8
#define SFF_A2_VCC_LALRM                  10
#define SFF_A2_VCC_HWARN                  12
#define SFF_A2_VCC_LWARN                  14

#define SFF_A2_BIAS                       100
#define SFF_A2_BIAS_HALRM                 16
#define SFF_A2_BIAS_LALRM                 18
#define SFF_A2_BIAS_HWARN                 20
#define SFF_A2_BIAS_LWARN                 22

#define SFF_A2_TX_PWR                     102
#define SFF_A2_TX_PWR_HALRM               24
#define SFF_A2_TX_PWR_LALRM               26
#define SFF_A2_TX_PWR_HWARN               28
#define SFF_A2_TX_PWR_LWARN               30

#define SFF_A2_RX_PWR                     104
#define SFF_A2_RX_PWR_HALRM               32
#define SFF_A2_RX_PWR_LALRM               34
#define SFF_A2_RX_PWR_HWARN               36
#define SFF_A2_RX_PWR_LWARN               38

#define SFF_A2_ALRM_FLG                   112
#define SFF_A2_WARN_FLG                   116

/* 32-bit little-endian calibration constants */
#define SFF_A2_CAL_RXPWR4                 56
#define SFF_A2_CAL_RXPWR3                 60
#define SFF_A2_CAL_RXPWR2                 64
#define SFF_A2_CAL_RXPWR1                 68
#define SFF_A2_CAL_RXPWR0                 72

/* 16-bit little endian calibration constants */
#define SFF_A2_CAL_TXI_SLP                76
#define SFF_A2_CAL_TXI_OFF                78
#define SFF_A2_CAL_TXPWR_SLP              80
#define SFF_A2_CAL_TXPWR_OFF              82
#define SFF_A2_CAL_T_SLP                  84
#define SFF_A2_CAL_T_OFF                  86
#define SFF_A2_CAL_V_SLP                  88
#define SFF_A2_CAL_V_OFF                  90

static struct sff8472_aw_flags {
	const char *str;        /* Human-readable string, null at the end */
	int offset;             /* A2-relative address offset */
	__u8 value;             /* Alarm is on if (offset & value) != 0. */
} sff8472_aw_flags[] = {
	{ "Laser bias current high alarm",   SFF_A2_ALRM_FLG, (1 << 3) },
	{ "Laser bias current low alarm",    SFF_A2_ALRM_FLG, (1 << 2) },
	{ "Laser bias current high warning", SFF_A2_WARN_FLG, (1 << 3) },
	{ "Laser bias current low warning",  SFF_A2_WARN_FLG, (1 << 2) },

	{ "Laser output power high alarm",   SFF_A2_ALRM_FLG, (1 << 1) },
	{ "Laser output power low alarm",    SFF_A2_ALRM_FLG, (1 << 0) },
	{ "Laser output power high warning", SFF_A2_WARN_FLG, (1 << 1) },
	{ "Laser output power low warning",  SFF_A2_WARN_FLG, (1 << 0) },

	{ "Module temperature high alarm",   SFF_A2_ALRM_FLG, (1 << 7) },
	{ "Module temperature low alarm",    SFF_A2_ALRM_FLG, (1 << 6) },
	{ "Module temperature high warning", SFF_A2_WARN_FLG, (1 << 7) },
	{ "Module temperature low warning",  SFF_A2_WARN_FLG, (1 << 6) },

	{ "Module voltage high alarm",   SFF_A2_ALRM_FLG, (1 << 5) },
	{ "Module voltage low alarm",    SFF_A2_ALRM_FLG, (1 << 4) },
	{ "Module voltage high warning", SFF_A2_WARN_FLG, (1 << 5) },
	{ "Module voltage low warning",  SFF_A2_WARN_FLG, (1 << 4) },

	{ "Laser rx power high alarm",   SFF_A2_ALRM_FLG + 1, (1 << 7) },
	{ "Laser rx power low alarm",    SFF_A2_ALRM_FLG + 1, (1 << 6) },
	{ "Laser rx power high warning", SFF_A2_WARN_FLG + 1, (1 << 7) },
	{ "Laser rx power low warning",  SFF_A2_WARN_FLG + 1, (1 << 6) },

	{ NULL, 0, 0 },
};

/* Most common case: 16-bit unsigned integer in a certain unit */
#define A2_OFFSET_TO_U16(offset) \
	(id[SFF_A2_BASE + (offset)] << 8 | id[SFF_A2_BASE + (offset) + 1])

/* Calibration slope is a number between 0.0 included and 256.0 excluded. */
#define A2_OFFSET_TO_SLP(offset) \
	(id[SFF_A2_BASE + (offset)] + id[SFF_A2_BASE + (offset) + 1] / 256.)

/* Calibration offset is an integer from -32768 to 32767 */
#define A2_OFFSET_TO_OFF(offset) \
	((__s16)A2_OFFSET_TO_U16(offset))

/* RXPWR(x) are IEEE-754 floating point numbers in big-endian format */
#define A2_OFFSET_TO_RXPWRx(offset) \
	(befloattoh((__u32 *)(id + SFF_A2_BASE + (offset))))

/*
 * 2-byte internal temperature conversions:
 * First byte is a signed 8-bit integer, which is the temp decimal part
 * Second byte are 1/256th of degree, which are added to the dec part.
 */
#define A2_OFFSET_TO_TEMP(offset) ((__s16)A2_OFFSET_TO_U16(offset))

static void sff8472_dom_parse(const __u8 *id, struct sff_diags *sd)
{
	sd->bias_cur[MCURR] = A2_OFFSET_TO_U16(SFF_A2_BIAS);
	sd->bias_cur[HALRM] = A2_OFFSET_TO_U16(SFF_A2_BIAS_HALRM);
	sd->bias_cur[LALRM] = A2_OFFSET_TO_U16(SFF_A2_BIAS_LALRM);
	sd->bias_cur[HWARN] = A2_OFFSET_TO_U16(SFF_A2_BIAS_HWARN);
	sd->bias_cur[LWARN] = A2_OFFSET_TO_U16(SFF_A2_BIAS_LWARN);

	sd->sfp_voltage[MCURR] = A2_OFFSET_TO_U16(SFF_A2_VCC);
	sd->sfp_voltage[HALRM] = A2_OFFSET_TO_U16(SFF_A2_VCC_HALRM);
	sd->sfp_voltage[LALRM] = A2_OFFSET_TO_U16(SFF_A2_VCC_LALRM);
	sd->sfp_voltage[HWARN] = A2_OFFSET_TO_U16(SFF_A2_VCC_HWARN);
	sd->sfp_voltage[LWARN] = A2_OFFSET_TO_U16(SFF_A2_VCC_LWARN);

	sd->tx_power[MCURR] = A2_OFFSET_TO_U16(SFF_A2_TX_PWR);
	sd->tx_power[HALRM] = A2_OFFSET_TO_U16(SFF_A2_TX_PWR_HALRM);
	sd->tx_power[LALRM] = A2_OFFSET_TO_U16(SFF_A2_TX_PWR_LALRM);
	sd->tx_power[HWARN] = A2_OFFSET_TO_U16(SFF_A2_TX_PWR_HWARN);
	sd->tx_power[LWARN] = A2_OFFSET_TO_U16(SFF_A2_TX_PWR_LWARN);

	sd->rx_power[MCURR] = A2_OFFSET_TO_U16(SFF_A2_RX_PWR);
	sd->rx_power[HALRM] = A2_OFFSET_TO_U16(SFF_A2_RX_PWR_HALRM);
	sd->rx_power[LALRM] = A2_OFFSET_TO_U16(SFF_A2_RX_PWR_LALRM);
	sd->rx_power[HWARN] = A2_OFFSET_TO_U16(SFF_A2_RX_PWR_HWARN);
	sd->rx_power[LWARN] = A2_OFFSET_TO_U16(SFF_A2_RX_PWR_LWARN);

	sd->sfp_temp[MCURR] = A2_OFFSET_TO_TEMP(SFF_A2_TEMP);
	sd->sfp_temp[HALRM] = A2_OFFSET_TO_TEMP(SFF_A2_TEMP_HALRM);
	sd->sfp_temp[LALRM] = A2_OFFSET_TO_TEMP(SFF_A2_TEMP_LALRM);
	sd->sfp_temp[HWARN] = A2_OFFSET_TO_TEMP(SFF_A2_TEMP_HWARN);
	sd->sfp_temp[LWARN] = A2_OFFSET_TO_TEMP(SFF_A2_TEMP_LWARN);
}

/* Converts to a float from a big-endian 4-byte source buffer. */
static float befloattoh(const __u32 *source)
{
	union {
		__u32 src;
		float dst;
	} converter;

	converter.src = ntohl(*source);
	return converter.dst;
}

static void sff8472_calibration(const __u8 *id, struct sff_diags *sd)
{
	int i;
	__u16 rx_reading;

	/* Calibration should occur for all values (threshold and current) */
	for (i = 0; i < ARRAY_SIZE(sd->bias_cur); ++i) {
		/*
		 * Apply calibration formula 1 (Temp., Voltage, Bias, Tx Power)
		 */
		sd->bias_cur[i]    *= A2_OFFSET_TO_SLP(SFF_A2_CAL_TXI_SLP);
		sd->tx_power[i]    *= A2_OFFSET_TO_SLP(SFF_A2_CAL_TXPWR_SLP);
		sd->sfp_voltage[i] *= A2_OFFSET_TO_SLP(SFF_A2_CAL_V_SLP);
		sd->sfp_temp[i]    *= A2_OFFSET_TO_SLP(SFF_A2_CAL_T_SLP);

		sd->bias_cur[i]    += A2_OFFSET_TO_OFF(SFF_A2_CAL_TXI_OFF);
		sd->tx_power[i]    += A2_OFFSET_TO_OFF(SFF_A2_CAL_TXPWR_OFF);
		sd->sfp_voltage[i] += A2_OFFSET_TO_OFF(SFF_A2_CAL_V_OFF);
		sd->sfp_temp[i]    += A2_OFFSET_TO_OFF(SFF_A2_CAL_T_OFF);

		/*
		 * Apply calibration formula 2 (Rx Power only)
		 */
		rx_reading = sd->rx_power[i];
		sd->rx_power[i]    = A2_OFFSET_TO_RXPWRx(SFF_A2_CAL_RXPWR0);
		sd->rx_power[i]    += rx_reading *
			A2_OFFSET_TO_RXPWRx(SFF_A2_CAL_RXPWR1);
		sd->rx_power[i]    += rx_reading *
			A2_OFFSET_TO_RXPWRx(SFF_A2_CAL_RXPWR2);
		sd->rx_power[i]    += rx_reading *
			A2_OFFSET_TO_RXPWRx(SFF_A2_CAL_RXPWR3);
	}
}

static void sff8472_parse_eeprom(const __u8 *id, struct sff_diags *sd)
{
	sd->supports_dom = id[SFF_A0_DOM] & SFF_A0_DOM_IMPL;
	sd->supports_alarms = id[SFF_A0_OPTIONS] & SFF_A0_OPTIONS_AW;
	sd->calibrated_ext = id[SFF_A0_DOM] & SFF_A0_DOM_EXTCAL;
	sd->rx_power_type = id[SFF_A0_DOM] & SFF_A0_DOM_PWRT;

	sff8472_dom_parse(id, sd);

	/*
	 * If the SFP is externally calibrated, we need to read calibration data
	 * and compensate the already stored readings.
	 */
	if (sd->calibrated_ext)
		sff8472_calibration(id, sd);
}

void sff8472_show_all(const __u8 *id)
{
	struct sff_diags sd = {0};
	char *rx_power_string = NULL;
	int i;

	sff8472_parse_eeprom(id, &sd);

	if (!sd.supports_dom) {
		printf("\t%-41s : No\n", "Optical diagnostics support");
		return;
	}
	printf("\t%-41s : Yes\n", "Optical diagnostics support");

	PRINT_BIAS("Laser bias current", sd.bias_cur[MCURR]);
	PRINT_xX_PWR("Laser output power", sd.tx_power[MCURR]);

	if (!sd.rx_power_type)
		rx_power_string = "Receiver signal OMA";
	else
		rx_power_string = "Receiver signal average optical power";

	PRINT_xX_PWR(rx_power_string, sd.rx_power[MCURR]);

	PRINT_TEMP("Module temperature", sd.sfp_temp[MCURR]);
	PRINT_VCC("Module voltage", sd.sfp_voltage[MCURR]);

	printf("\t%-41s : %s\n", "Alarm/warning flags implemented",
	       (sd.supports_alarms ? "Yes" : "No"));
	if (sd.supports_alarms) {

		for (i = 0; sff8472_aw_flags[i].str; ++i) {
			printf("\t%-41s : %s\n", sff8472_aw_flags[i].str,
			       id[SFF_A2_BASE + sff8472_aw_flags[i].offset]
			       & sff8472_aw_flags[i].value ? "On" : "Off");
		}
		sff_show_thresholds(sd);
	}
}