// SPDX-License-Identifier: GPL-2.0-only
/*
 * EMIF driver
 *
 * Copyright (C) 2012 Texas Instruments, Inc.
 *
 * Aneesh V <aneesh@ti.com>
 * Santosh Shilimkar <santosh.shilimkar@ti.com>
 */
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/reboot.h>
#include <linux/platform_data/emif_plat.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/pm.h>

#include "emif.h"
#include "jedec_ddr.h"
#include "of_memory.h"

/**
 * struct emif_data - Per device static data for driver's use
 * @duplicate:                  Whether the DDR devices attached to this EMIF
 *                              instance are exactly same as that on EMIF1. In
 *                              this case we can save some memory and processing
 * @temperature_level:          Maximum temperature of LPDDR2 devices attached
 *                              to this EMIF - read from MR4 register. If there
 *                              are two devices attached to this EMIF, this
 *                              value is the maximum of the two temperature
 *                              levels.
 * @node:                       node in the device list
 * @base:                       base address of memory-mapped IO registers.
 * @dev:                        device pointer.
 * @regs_cache:                 An array of 'struct emif_regs' that stores
 *                              calculated register values for different
 *                              frequencies, to avoid re-calculating them on
 *                              each DVFS transition.
 * @curr_regs:                  The set of register values used in the last
 *                              frequency change (i.e. corresponding to the
 *                              frequency in effect at the moment)
 * @plat_data:                  Pointer to saved platform data.
 * @debugfs_root:               dentry to the root folder for EMIF in debugfs
 * @np_ddr:                     Pointer to ddr device tree node
 */
struct emif_data {
        u8                              duplicate;
        u8                              temperature_level;
        u8                              lpmode;
        struct list_head                node;
        unsigned long                   irq_state;
        void __iomem                    *base;
        struct device                   *dev;
        struct emif_regs                *regs_cache[EMIF_MAX_NUM_FREQUENCIES];
        struct emif_regs                *curr_regs;
        struct emif_platform_data       *plat_data;
        struct dentry                   *debugfs_root;
        struct device_node              *np_ddr;
};

static struct emif_data *emif1;
static DEFINE_SPINLOCK(emif_lock);
static unsigned long    irq_state;
static LIST_HEAD(device_list);

#ifdef CONFIG_DEBUG_FS
static void do_emif_regdump_show(struct seq_file *s, struct emif_data *emif,
        struct emif_regs *regs)
{
        u32 type = emif->plat_data->device_info->type;
        u32 ip_rev = emif->plat_data->ip_rev;

        seq_printf(s, "EMIF register cache dump for %dMHz\n",
                regs->freq/1000000);

        seq_printf(s, "ref_ctrl_shdw\t: 0x%08x\n", regs->ref_ctrl_shdw);
        seq_printf(s, "sdram_tim1_shdw\t: 0x%08x\n", regs->sdram_tim1_shdw);
        seq_printf(s, "sdram_tim2_shdw\t: 0x%08x\n", regs->sdram_tim2_shdw);
        seq_printf(s, "sdram_tim3_shdw\t: 0x%08x\n", regs->sdram_tim3_shdw);

        if (ip_rev == EMIF_4D) {
                seq_printf(s, "read_idle_ctrl_shdw_normal\t: 0x%08x\n",
                        regs->read_idle_ctrl_shdw_normal);
                seq_printf(s, "read_idle_ctrl_shdw_volt_ramp\t: 0x%08x\n",
                        regs->read_idle_ctrl_shdw_volt_ramp);
        } else if (ip_rev == EMIF_4D5) {
                seq_printf(s, "dll_calib_ctrl_shdw_normal\t: 0x%08x\n",
                        regs->dll_calib_ctrl_shdw_normal);
                seq_printf(s, "dll_calib_ctrl_shdw_volt_ramp\t: 0x%08x\n",
                        regs->dll_calib_ctrl_shdw_volt_ramp);
        }

        if (type == DDR_TYPE_LPDDR2_S2 || type == DDR_TYPE_LPDDR2_S4) {
                seq_printf(s, "ref_ctrl_shdw_derated\t: 0x%08x\n",
                        regs->ref_ctrl_shdw_derated);
                seq_printf(s, "sdram_tim1_shdw_derated\t: 0x%08x\n",
                        regs->sdram_tim1_shdw_derated);
                seq_printf(s, "sdram_tim3_shdw_derated\t: 0x%08x\n",
                        regs->sdram_tim3_shdw_derated);
        }
}

static int emif_regdump_show(struct seq_file *s, void *unused)
{
        struct emif_data        *emif   = s->private;
        struct emif_regs        **regs_cache;
        int                     i;

        if (emif->duplicate)
                regs_cache = emif1->regs_cache;
        else
                regs_cache = emif->regs_cache;

        for (i = 0; i < EMIF_MAX_NUM_FREQUENCIES && regs_cache[i]; i++) {
                do_emif_regdump_show(s, emif, regs_cache[i]);
                seq_putc(s, '\n');
        }

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(emif_regdump);

static int emif_mr4_show(struct seq_file *s, void *unused)
{
        struct emif_data *emif = s->private;

        seq_printf(s, "MR4=%d\n", emif->temperature_level);
        return 0;
}

DEFINE_SHOW_ATTRIBUTE(emif_mr4);

static int __init_or_module emif_debugfs_init(struct emif_data *emif)
{
        emif->debugfs_root = debugfs_create_dir(dev_name(emif->dev), NULL);
        debugfs_create_file("regcache_dump", S_IRUGO, emif->debugfs_root, emif,
                            &emif_regdump_fops);
        debugfs_create_file("mr4", S_IRUGO, emif->debugfs_root, emif,
                            &emif_mr4_fops);
        return 0;
}

static void __exit emif_debugfs_exit(struct emif_data *emif)
{
        debugfs_remove_recursive(emif->debugfs_root);
        emif->debugfs_root = NULL;
}
#else
static inline int __init_or_module emif_debugfs_init(struct emif_data *emif)
{
        return 0;
}

static inline void __exit emif_debugfs_exit(struct emif_data *emif)
{
}
#endif

/*
 * Get bus width used by EMIF. Note that this may be different from the
 * bus width of the DDR devices used. For instance two 16-bit DDR devices
 * may be connected to a given CS of EMIF. In this case bus width as far
 * as EMIF is concerned is 32, where as the DDR bus width is 16 bits.
 */
static u32 get_emif_bus_width(struct emif_data *emif)
{
        u32             width;
        void __iomem    *base = emif->base;

        width = (readl(base + EMIF_SDRAM_CONFIG) & NARROW_MODE_MASK)
                        >> NARROW_MODE_SHIFT;
        width = width == 0 ? 32 : 16;

        return width;
}

static void set_lpmode(struct emif_data *emif, u8 lpmode)
{
        u32 temp;
        void __iomem *base = emif->base;

        /*
         * Workaround for errata i743 - LPDDR2 Power-Down State is Not
         * Efficient
         *
         * i743 DESCRIPTION:
         * The EMIF supports power-down state for low power. The EMIF
         * automatically puts the SDRAM into power-down after the memory is
         * not accessed for a defined number of cycles and the
         * EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE bit field is set to 0x4.
         * As the EMIF supports automatic output impedance calibration, a ZQ
         * calibration long command is issued every time it exits active
         * power-down and precharge power-down modes. The EMIF waits and
         * blocks any other command during this calibration.
         * The EMIF does not allow selective disabling of ZQ calibration upon
         * exit of power-down mode. Due to very short periods of power-down
         * cycles, ZQ calibration overhead creates bandwidth issues and
         * increases overall system power consumption. On the other hand,
         * issuing ZQ calibration long commands when exiting self-refresh is
         * still required.
         *
         * WORKAROUND
         * Because there is no power consumption benefit of the power-down due
         * to the calibration and there is a performance risk, the guideline
         * is to not allow power-down state and, therefore, to not have set
         * the EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE bit field to 0x4.
         */
        if ((emif->plat_data->ip_rev == EMIF_4D) &&
            (lpmode == EMIF_LP_MODE_PWR_DN)) {
                WARN_ONCE(1,
                          "REG_LP_MODE = LP_MODE_PWR_DN(4) is prohibited by erratum i743 switch to LP_MODE_SELF_REFRESH(2)\n");
                /* rollback LP_MODE to Self-refresh mode */
                lpmode = EMIF_LP_MODE_SELF_REFRESH;
        }

        temp = readl(base + EMIF_POWER_MANAGEMENT_CONTROL);
        temp &= ~LP_MODE_MASK;
        temp |= (lpmode << LP_MODE_SHIFT);
        writel(temp, base + EMIF_POWER_MANAGEMENT_CONTROL);
}

static void do_freq_update(void)
{
        struct emif_data *emif;

        /*
         * Workaround for errata i728: Disable LPMODE during FREQ_UPDATE
         *
         * i728 DESCRIPTION:
         * The EMIF automatically puts the SDRAM into self-refresh mode
         * after the EMIF has not performed accesses during
         * EMIF_PWR_MGMT_CTRL[7:4] REG_SR_TIM number of DDR clock cycles
         * and the EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE bit field is set
         * to 0x2. If during a small window the following three events
         * occur:
         * - The SR_TIMING counter expires
         * - And frequency change is requested
         * - And OCP access is requested
         * Then it causes instable clock on the DDR interface.
         *
         * WORKAROUND
         * To avoid the occurrence of the three events, the workaround
         * is to disable the self-refresh when requesting a frequency
         * change. Before requesting a frequency change the software must
         * program EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE to 0x0. When the
         * frequency change has been done, the software can reprogram
         * EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE to 0x2
         */
        list_for_each_entry(emif, &device_list, node) {
                if (emif->lpmode == EMIF_LP_MODE_SELF_REFRESH)
                        set_lpmode(emif, EMIF_LP_MODE_DISABLE);
        }

        /*
         * TODO: Do FREQ_UPDATE here when an API
         * is available for this as part of the new
         * clock framework
         */

        list_for_each_entry(emif, &device_list, node) {
                if (emif->lpmode == EMIF_LP_MODE_SELF_REFRESH)
                        set_lpmode(emif, EMIF_LP_MODE_SELF_REFRESH);
        }
}

/* Find addressing table entry based on the device's type and density */
static const struct lpddr2_addressing *get_addressing_table(
        const struct ddr_device_info *device_info)
{
        u32             index, type, density;

        type = device_info->type;
        density = device_info->density;

        switch (type) {
        case DDR_TYPE_LPDDR2_S4:
                index = density - 1;
                break;
        case DDR_TYPE_LPDDR2_S2:
                switch (density) {
                case DDR_DENSITY_1Gb:
                case DDR_DENSITY_2Gb:
                        index = density + 3;
                        break;
                default:
                        index = density - 1;
                }
                break;
        default:
                return NULL;
        }

        return &lpddr2_jedec_addressing_table[index];
}

static u32 get_zq_config_reg(const struct lpddr2_addressing *addressing,
                bool cs1_used, bool cal_resistors_per_cs)
{
        u32 zq = 0, val = 0;

        val = EMIF_ZQCS_INTERVAL_US * 1000 / addressing->tREFI_ns;
        zq |= val << ZQ_REFINTERVAL_SHIFT;

        val = DIV_ROUND_UP(T_ZQCL_DEFAULT_NS, T_ZQCS_DEFAULT_NS) - 1;
        zq |= val << ZQ_ZQCL_MULT_SHIFT;

        val = DIV_ROUND_UP(T_ZQINIT_DEFAULT_NS, T_ZQCL_DEFAULT_NS) - 1;
        zq |= val << ZQ_ZQINIT_MULT_SHIFT;

        zq |= ZQ_SFEXITEN_ENABLE << ZQ_SFEXITEN_SHIFT;

        if (cal_resistors_per_cs)
                zq |= ZQ_DUALCALEN_ENABLE << ZQ_DUALCALEN_SHIFT;
        else
                zq |= ZQ_DUALCALEN_DISABLE << ZQ_DUALCALEN_SHIFT;

        zq |= ZQ_CS0EN_MASK; /* CS0 is used for sure */

        val = cs1_used ? 1 : 0;
        zq |= val << ZQ_CS1EN_SHIFT;

        return zq;
}

static u32 get_temp_alert_config(const struct lpddr2_addressing *addressing,
                const struct emif_custom_configs *custom_configs, bool cs1_used,
                u32 sdram_io_width, u32 emif_bus_width)
{
        u32 alert = 0, interval, devcnt;

        if (custom_configs && (custom_configs->mask &
                                EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL))
                interval = custom_configs->temp_alert_poll_interval_ms;
        else
                interval = TEMP_ALERT_POLL_INTERVAL_DEFAULT_MS;

        interval *= 1000000;                    /* Convert to ns */
        interval /= addressing->tREFI_ns;       /* Convert to refresh cycles */
        alert |= (interval << TA_REFINTERVAL_SHIFT);

        /*
         * sdram_io_width is in 'log2(x) - 1' form. Convert emif_bus_width
         * also to this form and subtract to get TA_DEVCNT, which is
         * in log2(x) form.
         */
        emif_bus_width = __fls(emif_bus_width) - 1;
        devcnt = emif_bus_width - sdram_io_width;
        alert |= devcnt << TA_DEVCNT_SHIFT;

        /* DEVWDT is in 'log2(x) - 3' form */
        alert |= (sdram_io_width - 2) << TA_DEVWDT_SHIFT;

        alert |= 1 << TA_SFEXITEN_SHIFT;
        alert |= 1 << TA_CS0EN_SHIFT;
        alert |= (cs1_used ? 1 : 0) << TA_CS1EN_SHIFT;

        return alert;
}

static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
{
        u32 pwr_mgmt_ctrl       = 0, timeout;
        u32 lpmode              = EMIF_LP_MODE_SELF_REFRESH;
        u32 timeout_perf        = EMIF_LP_MODE_TIMEOUT_PERFORMANCE;
        u32 timeout_pwr         = EMIF_LP_MODE_TIMEOUT_POWER;
        u32 freq_threshold      = EMIF_LP_MODE_FREQ_THRESHOLD;
        u32 mask;
        u8 shift;

        struct emif_custom_configs *cust_cfgs = emif->plat_data->custom_configs;

        if (cust_cfgs && (cust_cfgs->mask & EMIF_CUSTOM_CONFIG_LPMODE)) {
                lpmode          = cust_cfgs->lpmode;
                timeout_perf    = cust_cfgs->lpmode_timeout_performance;
                timeout_pwr     = cust_cfgs->lpmode_timeout_power;
                freq_threshold  = cust_cfgs->lpmode_freq_threshold;
        }

        /* Timeout based on DDR frequency */
        timeout = freq >= freq_threshold ? timeout_perf : timeout_pwr;

        /*
         * The value to be set in register is "log2(timeout) - 3"
         * if timeout < 16 load 0 in register
         * if timeout is not a power of 2, round to next highest power of 2
         */
        if (timeout < 16) {
                timeout = 0;
        } else {
                if (timeout & (timeout - 1))
                        timeout <<= 1;
                timeout = __fls(timeout) - 3;
        }

        switch (lpmode) {
        case EMIF_LP_MODE_CLOCK_STOP:
                shift = CS_TIM_SHIFT;
                mask = CS_TIM_MASK;
                break;
        case EMIF_LP_MODE_SELF_REFRESH:
                /* Workaround for errata i735 */
                if (timeout < 6)
                        timeout = 6;

                shift = SR_TIM_SHIFT;
                mask = SR_TIM_MASK;
                break;
        case EMIF_LP_MODE_PWR_DN:
                shift = PD_TIM_SHIFT;
                mask = PD_TIM_MASK;
                break;
        case EMIF_LP_MODE_DISABLE:
        default:
                mask = 0;
                shift = 0;
                break;
        }
        /* Round to maximum in case of overflow, BUT warn! */
        if (lpmode != EMIF_LP_MODE_DISABLE && timeout > mask >> shift) {
                pr_err("TIMEOUT Overflow - lpmode=%d perf=%d pwr=%d freq=%d\n",
                       lpmode,
                       timeout_perf,
                       timeout_pwr,
                       freq_threshold);
                WARN(1, "timeout=0x%02x greater than 0x%02x. Using max\n",
                     timeout, mask >> shift);
                timeout = mask >> shift;
        }

        /* Setup required timing */
        pwr_mgmt_ctrl = (timeout << shift) & mask;
        /* setup a default mask for rest of the modes */
        pwr_mgmt_ctrl |= (SR_TIM_MASK | CS_TIM_MASK | PD_TIM_MASK) &
                          ~mask;

        /* No CS_TIM in EMIF_4D5 */
        if (ip_rev == EMIF_4D5)
                pwr_mgmt_ctrl &= ~CS_TIM_MASK;

        pwr_mgmt_ctrl |= lpmode << LP_MODE_SHIFT;

        return pwr_mgmt_ctrl;
}

/*
 * Get the temperature level of the EMIF instance:
 * Reads the MR4 register of attached SDRAM parts to find out the temperature
 * level. If there are two parts attached(one on each CS), then the temperature
 * level for the EMIF instance is the higher of the two temperatures.
 */
static void get_temperature_level(struct emif_data *emif)
{
        u32             temp, temperature_level;
        void __iomem    *base;

        base = emif->base;

        /* Read mode register 4 */
        writel(DDR_MR4, base + EMIF_LPDDR2_MODE_REG_CONFIG);
        temperature_level = readl(base + EMIF_LPDDR2_MODE_REG_DATA);
        temperature_level = (temperature_level & MR4_SDRAM_REF_RATE_MASK) >>
                                MR4_SDRAM_REF_RATE_SHIFT;

        if (emif->plat_data->device_info->cs1_used) {
                writel(DDR_MR4 | CS_MASK, base + EMIF_LPDDR2_MODE_REG_CONFIG);
                temp = readl(base + EMIF_LPDDR2_MODE_REG_DATA);
                temp = (temp & MR4_SDRAM_REF_RATE_MASK)
                                >> MR4_SDRAM_REF_RATE_SHIFT;
                temperature_level = max(temp, temperature_level);
        }

        /* treat everything less than nominal(3) in MR4 as nominal */
        if (unlikely(temperature_level < SDRAM_TEMP_NOMINAL))
                temperature_level = SDRAM_TEMP_NOMINAL;

        /* if we get reserved value in MR4 persist with the existing value */
        if (likely(temperature_level != SDRAM_TEMP_RESERVED_4))
                emif->temperature_level = temperature_level;
}

/*
 * setup_temperature_sensitive_regs() - set the timings for temperature
 * sensitive registers. This happens once at initialisation time based
 * on the temperature at boot time and subsequently based on the temperature
 * alert interrupt. Temperature alert can happen when the temperature
 * increases or drops. So this function can have the effect of either
 * derating the timings or going back to nominal values.
 */
static void setup_temperature_sensitive_regs(struct emif_data *emif,
                struct emif_regs *regs)
{
        u32             tim1, tim3, ref_ctrl, type;
        void __iomem    *base = emif->base;
        u32             temperature;

        type = emif->plat_data->device_info->type;

        tim1 = regs->sdram_tim1_shdw;
        tim3 = regs->sdram_tim3_shdw;
        ref_ctrl = regs->ref_ctrl_shdw;

        /* No de-rating for non-lpddr2 devices */
        if (type != DDR_TYPE_LPDDR2_S2 && type != DDR_TYPE_LPDDR2_S4)
                goto out;

        temperature = emif->temperature_level;
        if (temperature == SDRAM_TEMP_HIGH_DERATE_REFRESH) {
                ref_ctrl = regs->ref_ctrl_shdw_derated;
        } else if (temperature == SDRAM_TEMP_HIGH_DERATE_REFRESH_AND_TIMINGS) {
                tim1 = regs->sdram_tim1_shdw_derated;
                tim3 = regs->sdram_tim3_shdw_derated;
                ref_ctrl = regs->ref_ctrl_shdw_derated;
        }

out:
        writel(tim1, base + EMIF_SDRAM_TIMING_1_SHDW);
        writel(tim3, base + EMIF_SDRAM_TIMING_3_SHDW);
        writel(ref_ctrl, base + EMIF_SDRAM_REFRESH_CTRL_SHDW);
}

static irqreturn_t handle_temp_alert(void __iomem *base, struct emif_data *emif)
{
        u32             old_temp_level;
        irqreturn_t     ret = IRQ_HANDLED;
        struct emif_custom_configs *custom_configs;

        spin_lock_irqsave(&emif_lock, irq_state);
        old_temp_level = emif->temperature_level;
        get_temperature_level(emif);

        if (unlikely(emif->temperature_level == old_temp_level)) {
                goto out;
        } else if (!emif->curr_regs) {
                dev_err(emif->dev, "temperature alert before registers are calculated, not de-rating timings\n");
                goto out;
        }

        custom_configs = emif->plat_data->custom_configs;

        /*
         * IF we detect higher than "nominal rating" from DDR sensor
         * on an unsupported DDR part, shutdown system
         */
        if (custom_configs && !(custom_configs->mask &
                                EMIF_CUSTOM_CONFIG_EXTENDED_TEMP_PART)) {
                if (emif->temperature_level >= SDRAM_TEMP_HIGH_DERATE_REFRESH) {
                        dev_err(emif->dev,
                                "%s:NOT Extended temperature capable memory. Converting MR4=0x%02x as shutdown event\n",
                                __func__, emif->temperature_level);
                        /*
                         * Temperature far too high - do kernel_power_off()
                         * from thread context
                         */
                        emif->temperature_level = SDRAM_TEMP_VERY_HIGH_SHUTDOWN;
                        ret = IRQ_WAKE_THREAD;
                        goto out;
                }
        }

        if (emif->temperature_level < old_temp_level ||
                emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN) {
                /*
                 * Temperature coming down - defer handling to thread OR
                 * Temperature far too high - do kernel_power_off() from
                 * thread context
                 */
                ret = IRQ_WAKE_THREAD;
        } else {
                /* Temperature is going up - handle immediately */
                setup_temperature_sensitive_regs(emif, emif->curr_regs);
                do_freq_update();
        }

out:
        spin_unlock_irqrestore(&emif_lock, irq_state);
        return ret;
}

static irqreturn_t emif_interrupt_handler(int irq, void *dev_id)
{
        u32                     interrupts;
        struct emif_data        *emif = dev_id;
        void __iomem            *base = emif->base;
        struct device           *dev = emif->dev;
        irqreturn_t             ret = IRQ_HANDLED;

        /* Save the status and clear it */
        interrupts = readl(base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);
        writel(interrupts, base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);

        /*
         * Handle temperature alert
         * Temperature alert should be same for all ports
         * So, it's enough to process it only for one of the ports
         */
        if (interrupts & TA_SYS_MASK)
                ret = handle_temp_alert(base, emif);

        if (interrupts & ERR_SYS_MASK)
                dev_err(dev, "Access error from SYS port - %x\n", interrupts);

        if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE) {
                /* Save the status and clear it */
                interrupts = readl(base + EMIF_LL_OCP_INTERRUPT_STATUS);
                writel(interrupts, base + EMIF_LL_OCP_INTERRUPT_STATUS);

                if (interrupts & ERR_LL_MASK)
                        dev_err(dev, "Access error from LL port - %x\n",
                                interrupts);
        }

        return ret;
}

static irqreturn_t emif_threaded_isr(int irq, void *dev_id)
{
        struct emif_data        *emif = dev_id;

        if (emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN) {
                dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");

                /* If we have Power OFF ability, use it, else try restarting */
                if (pm_power_off) {
                        kernel_power_off();
                } else {
                        WARN(1, "FIXME: NO pm_power_off!!! trying restart\n");
                        kernel_restart("SDRAM Over-temp Emergency restart");
                }
                return IRQ_HANDLED;
        }

        spin_lock_irqsave(&emif_lock, irq_state);

        if (emif->curr_regs) {
                setup_temperature_sensitive_regs(emif, emif->curr_regs);
                do_freq_update();
        } else {
                dev_err(emif->dev, "temperature alert before registers are calculated, not de-rating timings\n");
        }

        spin_unlock_irqrestore(&emif_lock, irq_state);

        return IRQ_HANDLED;
}

static void clear_all_interrupts(struct emif_data *emif)
{
        void __iomem    *base = emif->base;

        writel(readl(base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS),
                base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);
        if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE)
                writel(readl(base + EMIF_LL_OCP_INTERRUPT_STATUS),
                        base + EMIF_LL_OCP_INTERRUPT_STATUS);
}

static void disable_and_clear_all_interrupts(struct emif_data *emif)
{
        void __iomem            *base = emif->base;

        /* Disable all interrupts */
        writel(readl(base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_SET),
                base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_CLEAR);
        if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE)
                writel(readl(base + EMIF_LL_OCP_INTERRUPT_ENABLE_SET),
                        base + EMIF_LL_OCP_INTERRUPT_ENABLE_CLEAR);

        /* Clear all interrupts */
        clear_all_interrupts(emif);
}

static int __init_or_module setup_interrupts(struct emif_data *emif, u32 irq)
{
        u32             interrupts, type;
        void __iomem    *base = emif->base;

        type = emif->plat_data->device_info->type;

        clear_all_interrupts(emif);

        /* Enable interrupts for SYS interface */
        interrupts = EN_ERR_SYS_MASK;
        if (type == DDR_TYPE_LPDDR2_S2 || type == DDR_TYPE_LPDDR2_S4)
                interrupts |= EN_TA_SYS_MASK;
        writel(interrupts, base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_SET);

        /* Enable interrupts for LL interface */
        if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE) {
                /* TA need not be enabled for LL */
                interrupts = EN_ERR_LL_MASK;
                writel(interrupts, base + EMIF_LL_OCP_INTERRUPT_ENABLE_SET);
        }

        /* setup IRQ handlers */
        return devm_request_threaded_irq(emif->dev, irq,
                                    emif_interrupt_handler,
                                    emif_threaded_isr,
                                    0, dev_name(emif->dev),
                                    emif);

}

static void __init_or_module emif_onetime_settings(struct emif_data *emif)
{
        u32                             pwr_mgmt_ctrl, zq, temp_alert_cfg;
        void __iomem                    *base = emif->base;
        const struct lpddr2_addressing  *addressing;
        const struct ddr_device_info    *device_info;

        device_info = emif->plat_data->device_info;
        addressing = get_addressing_table(device_info);

        /*
         * Init power management settings
         * We don't know the frequency yet. Use a high frequency
         * value for a conservative timeout setting
         */
        pwr_mgmt_ctrl = get_pwr_mgmt_ctrl(1000000000, emif,
                        emif->plat_data->ip_rev);
        emif->lpmode = (pwr_mgmt_ctrl & LP_MODE_MASK) >> LP_MODE_SHIFT;
        writel(pwr_mgmt_ctrl, base + EMIF_POWER_MANAGEMENT_CONTROL);

        /* Init ZQ calibration settings */
        zq = get_zq_config_reg(addressing, device_info->cs1_used,
                device_info->cal_resistors_per_cs);
        writel(zq, base + EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG);

        /* Check temperature level temperature level*/
        get_temperature_level(emif);
        if (emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN)
                dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");

        /* Init temperature polling */
        temp_alert_cfg = get_temp_alert_config(addressing,
                emif->plat_data->custom_configs, device_info->cs1_used,
                device_info->io_width, get_emif_bus_width(emif));
        writel(temp_alert_cfg, base + EMIF_TEMPERATURE_ALERT_CONFIG);

        /*
         * Program external PHY control registers that are not frequency
         * dependent
         */
        if (emif->plat_data->phy_type != EMIF_PHY_TYPE_INTELLIPHY)
                return;
        writel(EMIF_EXT_PHY_CTRL_1_VAL, base + EMIF_EXT_PHY_CTRL_1_SHDW);
        writel(EMIF_EXT_PHY_CTRL_5_VAL, base + EMIF_EXT_PHY_CTRL_5_SHDW);
        writel(EMIF_EXT_PHY_CTRL_6_VAL, base + EMIF_EXT_PHY_CTRL_6_SHDW);
        writel(EMIF_EXT_PHY_CTRL_7_VAL, base + EMIF_EXT_PHY_CTRL_7_SHDW);
        writel(EMIF_EXT_PHY_CTRL_8_VAL, base + EMIF_EXT_PHY_CTRL_8_SHDW);
        writel(EMIF_EXT_PHY_CTRL_9_VAL, base + EMIF_EXT_PHY_CTRL_9_SHDW);
        writel(EMIF_EXT_PHY_CTRL_10_VAL, base + EMIF_EXT_PHY_CTRL_10_SHDW);
        writel(EMIF_EXT_PHY_CTRL_11_VAL, base + EMIF_EXT_PHY_CTRL_11_SHDW);
        writel(EMIF_EXT_PHY_CTRL_12_VAL, base + EMIF_EXT_PHY_CTRL_12_SHDW);
        writel(EMIF_EXT_PHY_CTRL_13_VAL, base + EMIF_EXT_PHY_CTRL_13_SHDW);
        writel(EMIF_EXT_PHY_CTRL_14_VAL, base + EMIF_EXT_PHY_CTRL_14_SHDW);
        writel(EMIF_EXT_PHY_CTRL_15_VAL, base + EMIF_EXT_PHY_CTRL_15_SHDW);
        writel(EMIF_EXT_PHY_CTRL_16_VAL, base + EMIF_EXT_PHY_CTRL_16_SHDW);
        writel(EMIF_EXT_PHY_CTRL_17_VAL, base + EMIF_EXT_PHY_CTRL_17_SHDW);
        writel(EMIF_EXT_PHY_CTRL_18_VAL, base + EMIF_EXT_PHY_CTRL_18_SHDW);
        writel(EMIF_EXT_PHY_CTRL_19_VAL, base + EMIF_EXT_PHY_CTRL_19_SHDW);
        writel(EMIF_EXT_PHY_CTRL_20_VAL, base + EMIF_EXT_PHY_CTRL_20_SHDW);
        writel(EMIF_EXT_PHY_CTRL_21_VAL, base + EMIF_EXT_PHY_CTRL_21_SHDW);
        writel(EMIF_EXT_PHY_CTRL_22_VAL, base + EMIF_EXT_PHY_CTRL_22_SHDW);
        writel(EMIF_EXT_PHY_CTRL_23_VAL, base + EMIF_EXT_PHY_CTRL_23_SHDW);
        writel(EMIF_EXT_PHY_CTRL_24_VAL, base + EMIF_EXT_PHY_CTRL_24_SHDW);
}

static void get_default_timings(struct emif_data *emif)
{
        struct emif_platform_data *pd = emif->plat_data;

        pd->timings             = lpddr2_jedec_timings;
        pd->timings_arr_size    = ARRAY_SIZE(lpddr2_jedec_timings);

        dev_warn(emif->dev, "%s: using default timings\n", __func__);
}

static int is_dev_data_valid(u32 type, u32 density, u32 io_width, u32 phy_type,
                u32 ip_rev, struct device *dev)
{
        int valid;

        valid = (type == DDR_TYPE_LPDDR2_S4 ||
                        type == DDR_TYPE_LPDDR2_S2)
                && (density >= DDR_DENSITY_64Mb
                        && density <= DDR_DENSITY_8Gb)
                && (io_width >= DDR_IO_WIDTH_8
                        && io_width <= DDR_IO_WIDTH_32);

        /* Combinations of EMIF and PHY revisions that we support today */
        switch (ip_rev) {
        case EMIF_4D:
                valid = valid && (phy_type == EMIF_PHY_TYPE_ATTILAPHY);
                break;
        case EMIF_4D5:
                valid = valid && (phy_type == EMIF_PHY_TYPE_INTELLIPHY);
                break;
        default:
                valid = 0;
        }

        if (!valid)
                dev_err(dev, "%s: invalid DDR details\n", __func__);
        return valid;
}

static int is_custom_config_valid(struct emif_custom_configs *cust_cfgs,
                struct device *dev)
{
        int valid = 1;

        if ((cust_cfgs->mask & EMIF_CUSTOM_CONFIG_LPMODE) &&
                (cust_cfgs->lpmode != EMIF_LP_MODE_DISABLE))
                valid = cust_cfgs->lpmode_freq_threshold &&
                        cust_cfgs->lpmode_timeout_performance &&
                        cust_cfgs->lpmode_timeout_power;

        if (cust_cfgs->mask & EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL)
                valid = valid && cust_cfgs->temp_alert_poll_interval_ms;

        if (!valid)
                dev_warn(dev, "%s: invalid custom configs\n", __func__);

        return valid;
}

#if defined(CONFIG_OF)
static void __init_or_module of_get_custom_configs(struct device_node *np_emif,
                struct emif_data *emif)
{
        struct emif_custom_configs      *cust_cfgs = NULL;
        int                             len;
        const __be32                    *lpmode, *poll_intvl;

        lpmode = of_get_property(np_emif, "low-power-mode", &len);
        poll_intvl = of_get_property(np_emif, "temp-alert-poll-interval", &len);

        if (lpmode || poll_intvl)
                cust_cfgs = devm_kzalloc(emif->dev, sizeof(*cust_cfgs),
                        GFP_KERNEL);

        if (!cust_cfgs)
                return;

        if (lpmode) {
                cust_cfgs->mask |= EMIF_CUSTOM_CONFIG_LPMODE;
                cust_cfgs->lpmode = be32_to_cpup(lpmode);
                of_property_read_u32(np_emif,
                                "low-power-mode-timeout-performance",
                                &cust_cfgs->lpmode_timeout_performance);
                of_property_read_u32(np_emif,
                                "low-power-mode-timeout-power",
                                &cust_cfgs->lpmode_timeout_power);
                of_property_read_u32(np_emif,
                                "low-power-mode-freq-threshold",
                                &cust_cfgs->lpmode_freq_threshold);
        }

        if (poll_intvl) {
                cust_cfgs->mask |=
                                EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL;
                cust_cfgs->temp_alert_poll_interval_ms =
                                                be32_to_cpup(poll_intvl);
        }

        if (of_find_property(np_emif, "extended-temp-part", &len))
                cust_cfgs->mask |= EMIF_CUSTOM_CONFIG_EXTENDED_TEMP_PART;

        if (!is_custom_config_valid(cust_cfgs, emif->dev)) {
                devm_kfree(emif->dev, cust_cfgs);
                return;
        }

        emif->plat_data->custom_configs = cust_cfgs;
}

static void __init_or_module of_get_ddr_info(struct device_node *np_emif,
                struct device_node *np_ddr,
                struct ddr_device_info *dev_info)
{
        u32 density = 0, io_width = 0;
        int len;

        if (of_find_property(np_emif, "cs1-used", &len))
                dev_info->cs1_used = true;

        if (of_find_property(np_emif, "cal-resistor-per-cs", &len))
                dev_info->cal_resistors_per_cs = true;

        if (of_device_is_compatible(np_ddr, "jedec,lpddr2-s4"))
                dev_info->type = DDR_TYPE_LPDDR2_S4;
        else if (of_device_is_compatible(np_ddr, "jedec,lpddr2-s2"))
                dev_info->type = DDR_TYPE_LPDDR2_S2;

        of_property_read_u32(np_ddr, "density", &density);
        of_property_read_u32(np_ddr, "io-width", &io_width);

        /* Convert from density in Mb to the density encoding in jedc_ddr.h */
        if (density & (density - 1))
                dev_info->density = 0;
        else
                dev_info->density = __fls(density) - 5;

        /* Convert from io_width in bits to io_width encoding in jedc_ddr.h */
        if (io_width & (io_width - 1))
                dev_info->io_width = 0;
        else
                dev_info->io_width = __fls(io_width) - 1;
}

static struct emif_data * __init_or_module of_get_memory_device_details(
                struct device_node *np_emif, struct device *dev)
{
        struct emif_data                *emif = NULL;
        struct ddr_device_info          *dev_info = NULL;
        struct emif_platform_data       *pd = NULL;
        struct device_node              *np_ddr;
        int                             len;

        np_ddr = of_parse_phandle(np_emif, "device-handle", 0);
        if (!np_ddr)
                goto error;
        emif    = devm_kzalloc(dev, sizeof(struct emif_data), GFP_KERNEL);
        pd      = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
        dev_info = devm_kzalloc(dev, sizeof(*dev_info), GFP_KERNEL);

        if (!emif || !pd || !dev_info) {
                dev_err(dev, "%s: Out of memory!!\n",
                        __func__);
                goto error;
        }

        emif->plat_data         = pd;
        pd->device_info         = dev_info;
        emif->dev               = dev;
        emif->np_ddr            = np_ddr;
        emif->temperature_level = SDRAM_TEMP_NOMINAL;

        if (of_device_is_compatible(np_emif, "ti,emif-4d"))
                emif->plat_data->ip_rev = EMIF_4D;
        else if (of_device_is_compatible(np_emif, "ti,emif-4d5"))
                emif->plat_data->ip_rev = EMIF_4D5;

        of_property_read_u32(np_emif, "phy-type", &pd->phy_type);

        if (of_find_property(np_emif, "hw-caps-ll-interface", &len))
                pd->hw_caps |= EMIF_HW_CAPS_LL_INTERFACE;

        of_get_ddr_info(np_emif, np_ddr, dev_info);
        if (!is_dev_data_valid(pd->device_info->type, pd->device_info->density,
                        pd->device_info->io_width, pd->phy_type, pd->ip_rev,
                        emif->dev)) {
                dev_err(dev, "%s: invalid device data!!\n", __func__);
                goto error;
        }
        /*
         * For EMIF instances other than EMIF1 see if the devices connected
         * are exactly same as on EMIF1(which is typically the case). If so,
         * mark it as a duplicate of EMIF1. This will save some memory and
         * computation.
         */
        if (emif1 && emif1->np_ddr == np_ddr) {
                emif->duplicate = true;
                goto out;
        } else if (emif1) {
                dev_warn(emif->dev, "%s: Non-symmetric DDR geometry\n",
                        __func__);
        }

        of_get_custom_configs(np_emif, emif);
        emif->plat_data->timings = of_get_ddr_timings(np_ddr, emif->dev,
                                        emif->plat_data->device_info->type,
                                        &emif->plat_data->timings_arr_size);

        emif->plat_data->min_tck = of_get_min_tck(np_ddr, emif->dev);
        goto out;

error:
        return NULL;
out:
        return emif;
}

#else

static struct emif_data * __init_or_module of_get_memory_device_details(
                struct device_node *np_emif, struct device *dev)
{
        return NULL;
}

#endif

static struct emif_data *__init_or_module get_device_details(
                struct platform_device *pdev)
{
        u32                             size;
        struct emif_data                *emif = NULL;
        struct ddr_device_info          *dev_info;
        struct emif_custom_configs      *cust_cfgs;
        struct emif_platform_data       *pd;
        struct device                   *dev;
        void                            *temp;

        pd = pdev->dev.platform_data;
        dev = &pdev->dev;

        if (!(pd && pd->device_info && is_dev_data_valid(pd->device_info->type,
                        pd->device_info->density, pd->device_info->io_width,
                        pd->phy_type, pd->ip_rev, dev))) {
                dev_err(dev, "%s: invalid device data\n", __func__);
                goto error;
        }

        emif    = devm_kzalloc(dev, sizeof(*emif), GFP_KERNEL);
        temp    = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
        dev_info = devm_kzalloc(dev, sizeof(*dev_info), GFP_KERNEL);

        if (!emif || !pd || !dev_info) {
                dev_err(dev, "%s:%d: allocation error\n", __func__, __LINE__);
                goto error;
        }

        memcpy(temp, pd, sizeof(*pd));
        pd = temp;
        memcpy(dev_info, pd->device_info, sizeof(*dev_info));

        pd->device_info         = dev_info;
        emif->plat_data         = pd;
        emif->dev               = dev;
        emif->temperature_level = SDRAM_TEMP_NOMINAL;

        /*
         * For EMIF instances other than EMIF1 see if the devices connected
         * are exactly same as on EMIF1(which is typically the case). If so,
         * mark it as a duplicate of EMIF1 and skip copying timings data.
         * This will save some memory and some computation later.
         */
        emif->duplicate = emif1 && (memcmp(dev_info,
                emif1->plat_data->device_info,
                sizeof(struct ddr_device_info)) == 0);

        if (emif->duplicate) {
                pd->timings = NULL;
                pd->min_tck = NULL;
                goto out;
        } else if (emif1) {
                dev_warn(emif->dev, "%s: Non-symmetric DDR geometry\n",
                        __func__);
        }

        /*
         * Copy custom configs - ignore allocation error, if any, as
         * custom_configs is not very critical
         */
        cust_cfgs = pd->custom_configs;
        if (cust_cfgs && is_custom_config_valid(cust_cfgs, dev)) {
                temp = devm_kzalloc(dev, sizeof(*cust_cfgs), GFP_KERNEL);
                if (temp)
                        memcpy(temp, cust_cfgs, sizeof(*cust_cfgs));
                else
                        dev_warn(dev, "%s:%d: allocation error\n", __func__,
                                __LINE__);
                pd->custom_configs = temp;
        }

        /*
         * Copy timings and min-tck values from platform data. If it is not
         * available or if memory allocation fails, use JEDEC defaults
         */
        size = sizeof(struct lpddr2_timings) * pd->timings_arr_size;
        if (pd->timings) {
                temp = devm_kzalloc(dev, size, GFP_KERNEL);
                if (temp) {
                        memcpy(temp, pd->timings, size);
                        pd->timings = temp;
                } else {
                        dev_warn(dev, "%s:%d: allocation error\n", __func__,
                                __LINE__);
                        get_default_timings(emif);
                }
        } else {
                get_default_timings(emif);
        }

        if (pd->min_tck) {
                temp = devm_kzalloc(dev, sizeof(*pd->min_tck), GFP_KERNEL);
                if (temp) {
                        memcpy(temp, pd->min_tck, sizeof(*pd->min_tck));
                        pd->min_tck = temp;
                } else {
                        dev_warn(dev, "%s:%d: allocation error\n", __func__,
                                __LINE__);
                        pd->min_tck = &lpddr2_jedec_min_tck;
                }
        } else {
                pd->min_tck = &lpddr2_jedec_min_tck;
        }

out:
        return emif;

error:
        return NULL;
}

static int __init_or_module emif_probe(struct platform_device *pdev)
{
        struct emif_data        *emif;
        struct resource         *res;
        int                     irq;

        if (pdev->dev.of_node)
                emif = of_get_memory_device_details(pdev->dev.of_node, &pdev->dev);
        else
                emif = get_device_details(pdev);

        if (!emif) {
                pr_err("%s: error getting device data\n", __func__);
                goto error;
        }

        list_add(&emif->node, &device_list);

        /* Save pointers to each other in emif and device structures */
        emif->dev = &pdev->dev;
        platform_set_drvdata(pdev, emif);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        emif->base = devm_ioremap_resource(emif->dev, res);
        if (IS_ERR(emif->base))
                goto error;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                goto error;

        emif_onetime_settings(emif);
        emif_debugfs_init(emif);
        disable_and_clear_all_interrupts(emif);
        setup_interrupts(emif, irq);

        /* One-time actions taken on probing the first device */
        if (!emif1) {
                emif1 = emif;

                /*
                 * TODO: register notifiers for frequency and voltage
                 * change here once the respective frameworks are
                 * available
                 */
        }

        dev_info(&pdev->dev, "%s: device configured with addr = %p and IRQ%d\n",
                __func__, emif->base, irq);

        return 0;
error:
        return -ENODEV;
}

static int __exit emif_remove(struct platform_device *pdev)
{
        struct emif_data *emif = platform_get_drvdata(pdev);

        emif_debugfs_exit(emif);

        return 0;
}

static void emif_shutdown(struct platform_device *pdev)
{
        struct emif_data        *emif = platform_get_drvdata(pdev);

        disable_and_clear_all_interrupts(emif);
}

#if defined(CONFIG_OF)
static const struct of_device_id emif_of_match[] = {
                { .compatible = "ti,emif-4d" },
                { .compatible = "ti,emif-4d5" },
                {},
};
MODULE_DEVICE_TABLE(of, emif_of_match);
#endif

static struct platform_driver emif_driver = {
        .remove         = __exit_p(emif_remove),
        .shutdown       = emif_shutdown,
        .driver = {
                .name = "emif",
                .of_match_table = of_match_ptr(emif_of_match),
        },
};

module_platform_driver_probe(emif_driver, emif_probe);

MODULE_DESCRIPTION("TI EMIF SDRAM Controller Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:emif");
MODULE_AUTHOR("Texas Instruments Inc");