2 files changed, 1020 insertions, 4 deletions

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 7486d7ef0826..bd116eb8c738 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -21,6 +21,7 @@
 #include <linux/seq_file.h>
 #include <linux/module.h>
 #include <linux/list.h>
+#include <linux/spinlock.h>
 #include <memory/jedec_ddr.h>
 #include "emif.h"
 
@@ -37,20 +38,595 @@
  * @node:                       node in the device list
  * @base:                       base address of memory-mapped IO registers.
  * @dev:                        device pointer.
+ * @addressing                  table with addressing information from the spec
+ * @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.
  */
 struct emif_data {
         u8                              duplicate;
         u8                              temperature_level;
+        u8                              lpmode;
         struct list_head                node;
+        unsigned long                   irq_state;
         void __iomem                    *base;
         struct device                   *dev;
+        const struct lpddr2_addressing  *addressing;
+        struct emif_regs                *regs_cache[EMIF_MAX_NUM_FREQUENCIES];
+        struct emif_regs                *curr_regs;
         struct emif_platform_data       *plat_data;
 };
 
 static struct emif_data *emif1;
+static spinlock_t       emif_lock;
+static unsigned long    irq_state;
+static u32              t_ck; /* DDR clock period in ps */
 static LIST_HEAD(device_list);
 
+/*
+ * Calculate the period of DDR clock from frequency value
+ */
+static void set_ddr_clk_period(u32 freq)
+{
+        /* Divide 10^12 by frequency to get period in ps */
+        t_ck = (u32)DIV_ROUND_UP_ULL(1000000000000ull, freq);
+}
+
+/*
+ * Get the CL from SDRAM_CONFIG register
+ */
+static u32 get_cl(struct emif_data *emif)
+{
+        u32             cl;
+        void __iomem    *base = emif->base;
+
+        cl = (readl(base + EMIF_SDRAM_CONFIG) & CL_MASK) >> CL_SHIFT;
+
+        return cl;
+}
+
+static void set_lpmode(struct emif_data *emif, u8 lpmode)
+{
+        u32 temp;
+        void __iomem *base = emif->base;
+
+        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];
+}
+
+/*
+ * Find the the right timing table from the array of timing
+ * tables of the device using DDR clock frequency
+ */
+static const struct lpddr2_timings *get_timings_table(struct emif_data *emif,
+                u32 freq)
+{
+        u32                             i, min, max, freq_nearest;
+        const struct lpddr2_timings     *timings = NULL;
+        const struct lpddr2_timings     *timings_arr = emif->plat_data->timings;
+        struct                          device *dev = emif->dev;
+
+        /* Start with a very high frequency - 1GHz */
+        freq_nearest = 1000000000;
+
+        /*
+         * Find the timings table such that:
+         *  1. the frequency range covers the required frequency(safe) AND
+         *  2. the max_freq is closest to the required frequency(optimal)
+         */
+        for (i = 0; i < emif->plat_data->timings_arr_size; i++) {
+                max = timings_arr[i].max_freq;
+                min = timings_arr[i].min_freq;
+                if ((freq >= min) && (freq <= max) && (max < freq_nearest)) {
+                        freq_nearest = max;
+                        timings = &timings_arr[i];
+                }
+        }
+
+        if (!timings)
+                dev_err(dev, "%s: couldn't find timings for - %dHz\n",
+                        __func__, freq);
+
+        dev_dbg(dev, "%s: timings table: freq %d, speed bin freq %d\n",
+                __func__, freq, freq_nearest);
+
+        return timings;
+}
+
+static u32 get_sdram_ref_ctrl_shdw(u32 freq,
+                const struct lpddr2_addressing *addressing)
+{
+        u32 ref_ctrl_shdw = 0, val = 0, freq_khz, t_refi;
+
+        /* Scale down frequency and t_refi to avoid overflow */
+        freq_khz = freq / 1000;
+        t_refi = addressing->tREFI_ns / 100;
+
+        /*
+         * refresh rate to be set is 'tREFI(in us) * freq in MHz
+         * division by 10000 to account for change in units
+         */
+        val = t_refi * freq_khz / 10000;
+        ref_ctrl_shdw |= val << REFRESH_RATE_SHIFT;
+
+        return ref_ctrl_shdw;
+}
+
+static u32 get_sdram_tim_1_shdw(const struct lpddr2_timings *timings,
+                const struct lpddr2_min_tck *min_tck,
+                const struct lpddr2_addressing *addressing)
+{
+        u32 tim1 = 0, val = 0;
+
+        val = max(min_tck->tWTR, DIV_ROUND_UP(timings->tWTR, t_ck)) - 1;
+        tim1 |= val << T_WTR_SHIFT;
+
+        if (addressing->num_banks == B8)
+                val = DIV_ROUND_UP(timings->tFAW, t_ck*4);
+        else
+                val = max(min_tck->tRRD, DIV_ROUND_UP(timings->tRRD, t_ck));
+        tim1 |= (val - 1) << T_RRD_SHIFT;
+
+        val = DIV_ROUND_UP(timings->tRAS_min + timings->tRPab, t_ck) - 1;
+        tim1 |= val << T_RC_SHIFT;
+
+        val = max(min_tck->tRASmin, DIV_ROUND_UP(timings->tRAS_min, t_ck));
+        tim1 |= (val - 1) << T_RAS_SHIFT;
+
+        val = max(min_tck->tWR, DIV_ROUND_UP(timings->tWR, t_ck)) - 1;
+        tim1 |= val << T_WR_SHIFT;
+
+        val = max(min_tck->tRCD, DIV_ROUND_UP(timings->tRCD, t_ck)) - 1;
+        tim1 |= val << T_RCD_SHIFT;
+
+        val = max(min_tck->tRPab, DIV_ROUND_UP(timings->tRPab, t_ck)) - 1;
+        tim1 |= val << T_RP_SHIFT;
+
+        return tim1;
+}
+
+static u32 get_sdram_tim_1_shdw_derated(const struct lpddr2_timings *timings,
+                const struct lpddr2_min_tck *min_tck,
+                const struct lpddr2_addressing *addressing)
+{
+        u32 tim1 = 0, val = 0;
+
+        val = max(min_tck->tWTR, DIV_ROUND_UP(timings->tWTR, t_ck)) - 1;
+        tim1 = val << T_WTR_SHIFT;
+
+        /*
+         * tFAW is approximately 4 times tRRD. So add 1875*4 = 7500ps
+         * to tFAW for de-rating
+         */
+        if (addressing->num_banks == B8) {
+                val = DIV_ROUND_UP(timings->tFAW + 7500, 4 * t_ck) - 1;
+        } else {
+                val = DIV_ROUND_UP(timings->tRRD + 1875, t_ck);
+                val = max(min_tck->tRRD, val) - 1;
+        }
+        tim1 |= val << T_RRD_SHIFT;
+
+        val = DIV_ROUND_UP(timings->tRAS_min + timings->tRPab + 1875, t_ck);
+        tim1 |= (val - 1) << T_RC_SHIFT;
+
+        val = DIV_ROUND_UP(timings->tRAS_min + 1875, t_ck);
+        val = max(min_tck->tRASmin, val) - 1;
+        tim1 |= val << T_RAS_SHIFT;
+
+        val = max(min_tck->tWR, DIV_ROUND_UP(timings->tWR, t_ck)) - 1;
+        tim1 |= val << T_WR_SHIFT;
+
+        val = max(min_tck->tRCD, DIV_ROUND_UP(timings->tRCD + 1875, t_ck));
+        tim1 |= (val - 1) << T_RCD_SHIFT;
+
+        val = max(min_tck->tRPab, DIV_ROUND_UP(timings->tRPab + 1875, t_ck));
+        tim1 |= (val - 1) << T_RP_SHIFT;
+
+        return tim1;
+}
+
+static u32 get_sdram_tim_2_shdw(const struct lpddr2_timings *timings,
+                const struct lpddr2_min_tck *min_tck,
+                const struct lpddr2_addressing *addressing,
+                u32 type)
+{
+        u32 tim2 = 0, val = 0;
+
+        val = min_tck->tCKE - 1;
+        tim2 |= val << T_CKE_SHIFT;
+
+        val = max(min_tck->tRTP, DIV_ROUND_UP(timings->tRTP, t_ck)) - 1;
+        tim2 |= val << T_RTP_SHIFT;
+
+        /* tXSNR = tRFCab_ps + 10 ns(tRFCab_ps for LPDDR2). */
+        val = DIV_ROUND_UP(addressing->tRFCab_ps + 10000, t_ck) - 1;
+        tim2 |= val << T_XSNR_SHIFT;
+
+        /* XSRD same as XSNR for LPDDR2 */
+        tim2 |= val << T_XSRD_SHIFT;
+
+        val = max(min_tck->tXP, DIV_ROUND_UP(timings->tXP, t_ck)) - 1;
+        tim2 |= val << T_XP_SHIFT;
+
+        return tim2;
+}
+
+static u32 get_sdram_tim_3_shdw(const struct lpddr2_timings *timings,
+                const struct lpddr2_min_tck *min_tck,
+                const struct lpddr2_addressing *addressing,
+                u32 type, u32 ip_rev, u32 derated)
+{
+        u32 tim3 = 0, val = 0, t_dqsck;
+
+        val = timings->tRAS_max_ns / addressing->tREFI_ns - 1;
+        val = val > 0xF ? 0xF : val;
+        tim3 |= val << T_RAS_MAX_SHIFT;
+
+        val = DIV_ROUND_UP(addressing->tRFCab_ps, t_ck) - 1;
+        tim3 |= val << T_RFC_SHIFT;
+
+        t_dqsck = (derated == EMIF_DERATED_TIMINGS) ?
+                timings->tDQSCK_max_derated : timings->tDQSCK_max;
+        if (ip_rev == EMIF_4D5)
+                val = DIV_ROUND_UP(t_dqsck + 1000, t_ck) - 1;
+        else
+                val = DIV_ROUND_UP(t_dqsck, t_ck) - 1;
+
+        tim3 |= val << T_TDQSCKMAX_SHIFT;
+
+        val = DIV_ROUND_UP(timings->tZQCS, t_ck) - 1;
+        tim3 |= val << ZQ_ZQCS_SHIFT;
+
+        val = DIV_ROUND_UP(timings->tCKESR, t_ck);
+        val = max(min_tck->tCKESR, val) - 1;
+        tim3 |= val << T_CKESR_SHIFT;
+
+        if (ip_rev == EMIF_4D5) {
+                tim3 |= (EMIF_T_CSTA - 1) << T_CSTA_SHIFT;
+
+                val = DIV_ROUND_UP(EMIF_T_PDLL_UL, 128) - 1;
+                tim3 |= val << T_PDLL_UL_SHIFT;
+        }
+
+        return tim3;
+}
+
+static u32 get_read_idle_ctrl_shdw(u8 volt_ramp)
+{
+        u32 idle = 0, val = 0;
+
+        /*
+         * Maximum value in normal conditions and increased frequency
+         * when voltage is ramping
+         */
+        if (volt_ramp)
+                val = READ_IDLE_INTERVAL_DVFS / t_ck / 64 - 1;
+        else
+                val = 0x1FF;
+
+        /*
+         * READ_IDLE_CTRL register in EMIF4D has same offset and fields
+         * as DLL_CALIB_CTRL in EMIF4D5, so use the same shifts
+         */
+        idle |= val << DLL_CALIB_INTERVAL_SHIFT;
+        idle |= EMIF_READ_IDLE_LEN_VAL << ACK_WAIT_SHIFT;
+
+        return idle;
+}
+
+static u32 get_dll_calib_ctrl_shdw(u8 volt_ramp)
+{
+        u32 calib = 0, val = 0;
+
+        if (volt_ramp == DDR_VOLTAGE_RAMPING)
+                val = DLL_CALIB_INTERVAL_DVFS / t_ck / 16 - 1;
+        else
+                val = 0; /* Disabled when voltage is stable */
+
+        calib |= val << DLL_CALIB_INTERVAL_SHIFT;
+        calib |= DLL_CALIB_ACK_WAIT_VAL << ACK_WAIT_SHIFT;
+
+        return calib;
+}
+
+static u32 get_ddr_phy_ctrl_1_attilaphy_4d(const struct lpddr2_timings *timings,
+        u32 freq, u8 RL)
+{
+        u32 phy = EMIF_DDR_PHY_CTRL_1_BASE_VAL_ATTILAPHY, val = 0;
+
+        val = RL + DIV_ROUND_UP(timings->tDQSCK_max, t_ck) - 1;
+        phy |= val << READ_LATENCY_SHIFT_4D;
+
+        if (freq <= 100000000)
+                val = EMIF_DLL_SLAVE_DLY_CTRL_100_MHZ_AND_LESS_ATTILAPHY;
+        else if (freq <= 200000000)
+                val = EMIF_DLL_SLAVE_DLY_CTRL_200_MHZ_ATTILAPHY;
+        else
+                val = EMIF_DLL_SLAVE_DLY_CTRL_400_MHZ_ATTILAPHY;
+
+        phy |= val << DLL_SLAVE_DLY_CTRL_SHIFT_4D;
+
+        return phy;
+}
+
+static u32 get_phy_ctrl_1_intelliphy_4d5(u32 freq, u8 cl)
+{
+        u32 phy = EMIF_DDR_PHY_CTRL_1_BASE_VAL_INTELLIPHY, half_delay;
+
+        /*
+         * DLL operates at 266 MHz. If DDR frequency is near 266 MHz,
+         * half-delay is not needed else set half-delay
+         */
+        if (freq >= 265000000 && freq < 267000000)
+                half_delay = 0;
+        else
+                half_delay = 1;
+
+        phy |= half_delay << DLL_HALF_DELAY_SHIFT_4D5;
+        phy |= ((cl + DIV_ROUND_UP(EMIF_PHY_TOTAL_READ_LATENCY_INTELLIPHY_PS,
+                        t_ck) - 1) << READ_LATENCY_SHIFT_4D5);
+
+        return phy;
+}
+
+static u32 get_ext_phy_ctrl_2_intelliphy_4d5(void)
+{
+        u32 fifo_we_slave_ratio;
+
+        fifo_we_slave_ratio =  DIV_ROUND_CLOSEST(
+                EMIF_INTELLI_PHY_DQS_GATE_OPENING_DELAY_PS * 256 , t_ck);
+
+        return fifo_we_slave_ratio | fifo_we_slave_ratio << 11 |
+                fifo_we_slave_ratio << 22;
+}
+
+static u32 get_ext_phy_ctrl_3_intelliphy_4d5(void)
+{
+        u32 fifo_we_slave_ratio;
+
+        fifo_we_slave_ratio =  DIV_ROUND_CLOSEST(
+                EMIF_INTELLI_PHY_DQS_GATE_OPENING_DELAY_PS * 256 , t_ck);
+
+        return fifo_we_slave_ratio >> 10 | fifo_we_slave_ratio << 1 |
+                fifo_we_slave_ratio << 12 | fifo_we_slave_ratio << 23;
+}
+
+static u32 get_ext_phy_ctrl_4_intelliphy_4d5(void)
+{
+        u32 fifo_we_slave_ratio;
+
+        fifo_we_slave_ratio =  DIV_ROUND_CLOSEST(
+                EMIF_INTELLI_PHY_DQS_GATE_OPENING_DELAY_PS * 256 , t_ck);
+
+        return fifo_we_slave_ratio >> 9 | fifo_we_slave_ratio << 2 |
+                fifo_we_slave_ratio << 13;
+}
+
+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;
+
+        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) {
+                timeout = 0;
+        } else {
+                timeout = __fls(timeout) - 3;
+                if (timeout & (timeout - 1))
+                        timeout++;
+        }
+
+        switch (lpmode) {
+        case EMIF_LP_MODE_CLOCK_STOP:
+                pwr_mgmt_ctrl = (timeout << CS_TIM_SHIFT) |
+                                        SR_TIM_MASK | PD_TIM_MASK;
+                break;
+        case EMIF_LP_MODE_SELF_REFRESH:
+                /* Workaround for errata i735 */
+                if (timeout < 6)
+                        timeout = 6;
+
+                pwr_mgmt_ctrl = (timeout << SR_TIM_SHIFT) |
+                                        CS_TIM_MASK | PD_TIM_MASK;
+                break;
+        case EMIF_LP_MODE_PWR_DN:
+                pwr_mgmt_ctrl = (timeout << PD_TIM_SHIFT) |
+                                        CS_TIM_MASK | SR_TIM_MASK;
+                break;
+        case EMIF_LP_MODE_DISABLE:
+        default:
+                pwr_mgmt_ctrl = CS_TIM_MASK |
+                                        PD_TIM_MASK | SR_TIM_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;
+}
+
+/*
+ * Program EMIF shadow registers that are not dependent on temperature
+ * or voltage
+ */
+static void setup_registers(struct emif_data *emif, struct emif_regs *regs)
+{
+        void __iomem    *base = emif->base;
+
+        writel(regs->sdram_tim2_shdw, base + EMIF_SDRAM_TIMING_2_SHDW);
+        writel(regs->phy_ctrl_1_shdw, base + EMIF_DDR_PHY_CTRL_1_SHDW);
+
+        /* Settings specific for EMIF4D5 */
+        if (emif->plat_data->ip_rev != EMIF_4D5)
+                return;
+        writel(regs->ext_phy_ctrl_2_shdw, base + EMIF_EXT_PHY_CTRL_2_SHDW);
+        writel(regs->ext_phy_ctrl_3_shdw, base + EMIF_EXT_PHY_CTRL_3_SHDW);
+        writel(regs->ext_phy_ctrl_4_shdw, base + EMIF_EXT_PHY_CTRL_4_SHDW);
+}
+
+/*
+ * When voltage ramps dll calibration and forced read idle should
+ * happen more often
+ */
+static void setup_volt_sensitive_regs(struct emif_data *emif,
+                struct emif_regs *regs, u32 volt_state)
+{
+        u32             calib_ctrl;
+        void __iomem    *base = emif->base;
+
+        /*
+         * EMIF_READ_IDLE_CTRL in EMIF4D refers to the same register as
+         * EMIF_DLL_CALIB_CTRL in EMIF4D5 and dll_calib_ctrl_shadow_*
+         * is an alias of the respective read_idle_ctrl_shdw_* (members of
+         * a union). So, the below code takes care of both cases
+         */
+        if (volt_state == DDR_VOLTAGE_RAMPING)
+                calib_ctrl = regs->dll_calib_ctrl_shdw_volt_ramp;
+        else
+                calib_ctrl = regs->dll_calib_ctrl_shdw_normal;
+
+        writel(calib_ctrl, base + EMIF_DLL_CALIB_CTRL_SHDW);
+}
+
+/*
+ * 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 void get_default_timings(struct emif_data *emif)
 {
         struct emif_platform_data *pd = emif->plat_data;
@@ -234,10 +810,8 @@ static int __init_or_module emif_probe(struct platform_device *pdev)
                 goto error;
         }
 
-        if (!emif1)
-                emif1 = emif;
-
         list_add(&emif->node, &device_list);
+        emif->addressing = get_addressing_table(emif->plat_data->device_info);
 
         /* Save pointers to each other in emif and device structures */
         emif->dev = &pdev->dev;
@@ -257,6 +831,18 @@ static int __init_or_module emif_probe(struct platform_device *pdev)
                 goto error;
         }
 
+        /* One-time actions taken on probing the first device */
+        if (!emif1) {
+                emif1 = emif;
+                spin_lock_init(&emif_lock);
+
+                /*
+                 * 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\n",
                 __func__, emif->base);
 
@@ -265,6 +851,308 @@ error:
         return -ENODEV;
 }
 
+static int get_emif_reg_values(struct emif_data *emif, u32 freq,
+                struct emif_regs *regs)
+{
+        u32                             cs1_used, ip_rev, phy_type;
+        u32                             cl, type;
+        const struct lpddr2_timings     *timings;
+        const struct lpddr2_min_tck     *min_tck;
+        const struct ddr_device_info    *device_info;
+        const struct lpddr2_addressing  *addressing;
+        struct emif_data                *emif_for_calc;
+        struct device                   *dev;
+        const struct emif_custom_configs *custom_configs;
+
+        dev = emif->dev;
+        /*
+         * If the devices on this EMIF instance is duplicate of EMIF1,
+         * use EMIF1 details for the calculation
+         */
+        emif_for_calc   = emif->duplicate ? emif1 : emif;
+        timings         = get_timings_table(emif_for_calc, freq);
+        addressing      = emif_for_calc->addressing;
+        if (!timings || !addressing) {
+                dev_err(dev, "%s: not enough data available for %dHz",
+                        __func__, freq);
+                return -1;
+        }
+
+        device_info     = emif_for_calc->plat_data->device_info;
+        type            = device_info->type;
+        cs1_used        = device_info->cs1_used;
+        ip_rev          = emif_for_calc->plat_data->ip_rev;
+        phy_type        = emif_for_calc->plat_data->phy_type;
+
+        min_tck         = emif_for_calc->plat_data->min_tck;
+        custom_configs  = emif_for_calc->plat_data->custom_configs;
+
+        set_ddr_clk_period(freq);
+
+        regs->ref_ctrl_shdw = get_sdram_ref_ctrl_shdw(freq, addressing);
+        regs->sdram_tim1_shdw = get_sdram_tim_1_shdw(timings, min_tck,
+                        addressing);
+        regs->sdram_tim2_shdw = get_sdram_tim_2_shdw(timings, min_tck,
+                        addressing, type);
+        regs->sdram_tim3_shdw = get_sdram_tim_3_shdw(timings, min_tck,
+                addressing, type, ip_rev, EMIF_NORMAL_TIMINGS);
+
+        cl = get_cl(emif);
+
+        if (phy_type == EMIF_PHY_TYPE_ATTILAPHY && ip_rev == EMIF_4D) {
+                regs->phy_ctrl_1_shdw = get_ddr_phy_ctrl_1_attilaphy_4d(
+                        timings, freq, cl);
+        } else if (phy_type == EMIF_PHY_TYPE_INTELLIPHY && ip_rev == EMIF_4D5) {
+                regs->phy_ctrl_1_shdw = get_phy_ctrl_1_intelliphy_4d5(freq, cl);
+                regs->ext_phy_ctrl_2_shdw = get_ext_phy_ctrl_2_intelliphy_4d5();
+                regs->ext_phy_ctrl_3_shdw = get_ext_phy_ctrl_3_intelliphy_4d5();
+                regs->ext_phy_ctrl_4_shdw = get_ext_phy_ctrl_4_intelliphy_4d5();
+        } else {
+                return -1;
+        }
+
+        /* Only timeout values in pwr_mgmt_ctrl_shdw register */
+        regs->pwr_mgmt_ctrl_shdw =
+                get_pwr_mgmt_ctrl(freq, emif_for_calc, ip_rev) &
+                (CS_TIM_MASK | SR_TIM_MASK | PD_TIM_MASK);
+
+        if (ip_rev & EMIF_4D) {
+                regs->read_idle_ctrl_shdw_normal =
+                        get_read_idle_ctrl_shdw(DDR_VOLTAGE_STABLE);
+
+                regs->read_idle_ctrl_shdw_volt_ramp =
+                        get_read_idle_ctrl_shdw(DDR_VOLTAGE_RAMPING);
+        } else if (ip_rev & EMIF_4D5) {
+                regs->dll_calib_ctrl_shdw_normal =
+                        get_dll_calib_ctrl_shdw(DDR_VOLTAGE_STABLE);
+
+                regs->dll_calib_ctrl_shdw_volt_ramp =
+                        get_dll_calib_ctrl_shdw(DDR_VOLTAGE_RAMPING);
+        }
+
+        if (type == DDR_TYPE_LPDDR2_S2 || type == DDR_TYPE_LPDDR2_S4) {
+                regs->ref_ctrl_shdw_derated = get_sdram_ref_ctrl_shdw(freq / 4,
+                        addressing);
+
+                regs->sdram_tim1_shdw_derated =
+                        get_sdram_tim_1_shdw_derated(timings, min_tck,
+                                addressing);
+
+                regs->sdram_tim3_shdw_derated = get_sdram_tim_3_shdw(timings,
+                        min_tck, addressing, type, ip_rev,
+                        EMIF_DERATED_TIMINGS);
+        }
+
+        regs->freq = freq;
+
+        return 0;
+}
+
+/*
+ * get_regs() - gets the cached emif_regs structure for a given EMIF instance
+ * given frequency(freq):
+ *
+ * As an optimisation, every EMIF instance other than EMIF1 shares the
+ * register cache with EMIF1 if the devices connected on this instance
+ * are same as that on EMIF1(indicated by the duplicate flag)
+ *
+ * If we do not have an entry corresponding to the frequency given, we
+ * allocate a new entry and calculate the values
+ *
+ * Upon finding the right reg dump, save it in curr_regs. It can be
+ * directly used for thermal de-rating and voltage ramping changes.
+ */
+static struct emif_regs *get_regs(struct emif_data *emif, u32 freq)
+{
+        int                     i;
+        struct emif_regs        **regs_cache;
+        struct emif_regs        *regs = NULL;
+        struct device           *dev;
+
+        dev = emif->dev;
+        if (emif->curr_regs && emif->curr_regs->freq == freq) {
+                dev_dbg(dev, "%s: using curr_regs - %u Hz", __func__, freq);
+                return emif->curr_regs;
+        }
+
+        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++) {
+                if (regs_cache[i]->freq == freq) {
+                        regs = regs_cache[i];
+                        dev_dbg(dev,
+                                "%s: reg dump found in reg cache for %u Hz\n",
+                                __func__, freq);
+                        break;
+                }
+        }
+
+        /*
+         * If we don't have an entry for this frequency in the cache create one
+         * and calculate the values
+         */
+        if (!regs) {
+                regs = devm_kzalloc(emif->dev, sizeof(*regs), GFP_ATOMIC);
+                if (!regs)
+                        return NULL;
+
+                if (get_emif_reg_values(emif, freq, regs)) {
+                        devm_kfree(emif->dev, regs);
+                        return NULL;
+                }
+
+                /*
+                 * Now look for an un-used entry in the cache and save the
+                 * newly created struct. If there are no free entries
+                 * over-write the last entry
+                 */
+                for (i = 0; i < EMIF_MAX_NUM_FREQUENCIES && regs_cache[i]; i++)
+                        ;
+
+                if (i >= EMIF_MAX_NUM_FREQUENCIES) {
+                        dev_warn(dev, "%s: regs_cache full - reusing a slot!!\n",
+                                __func__);
+                        i = EMIF_MAX_NUM_FREQUENCIES - 1;
+                        devm_kfree(emif->dev, regs_cache[i]);
+                }
+                regs_cache[i] = regs;
+        }
+
+        return regs;
+}
+
+static void do_volt_notify_handling(struct emif_data *emif, u32 volt_state)
+{
+        dev_dbg(emif->dev, "%s: voltage notification : %d", __func__,
+                volt_state);
+
+        if (!emif->curr_regs) {
+                dev_err(emif->dev,
+                        "%s: volt-notify before registers are ready: %d\n",
+                        __func__, volt_state);
+                return;
+        }
+
+        setup_volt_sensitive_regs(emif, emif->curr_regs, volt_state);
+}
+
+/*
+ * TODO: voltage notify handling should be hooked up to
+ * regulator framework as soon as the necessary support
+ * is available in mainline kernel. This function is un-used
+ * right now.
+ */
+static void __attribute__((unused)) volt_notify_handling(u32 volt_state)
+{
+        struct emif_data *emif;
+
+        spin_lock_irqsave(&emif_lock, irq_state);
+
+        list_for_each_entry(emif, &device_list, node)
+                do_volt_notify_handling(emif, volt_state);
+        do_freq_update();
+
+        spin_unlock_irqrestore(&emif_lock, irq_state);
+}
+
+static void do_freq_pre_notify_handling(struct emif_data *emif, u32 new_freq)
+{
+        struct emif_regs *regs;
+
+        regs = get_regs(emif, new_freq);
+        if (!regs)
+                return;
+
+        emif->curr_regs = regs;
+
+        /*
+         * Update the shadow registers:
+         * Temperature and voltage-ramp sensitive settings are also configured
+         * in terms of DDR cycles. So, we need to update them too when there
+         * is a freq change
+         */
+        dev_dbg(emif->dev, "%s: setting up shadow registers for %uHz",
+                __func__, new_freq);
+        setup_registers(emif, regs);
+        setup_temperature_sensitive_regs(emif, regs);
+        setup_volt_sensitive_regs(emif, regs, DDR_VOLTAGE_STABLE);
+
+        /*
+         * Part of workaround for errata i728. See do_freq_update()
+         * for more details
+         */
+        if (emif->lpmode == EMIF_LP_MODE_SELF_REFRESH)
+                set_lpmode(emif, EMIF_LP_MODE_DISABLE);
+}
+
+/*
+ * TODO: frequency notify handling should be hooked up to
+ * clock framework as soon as the necessary support is
+ * available in mainline kernel. This function is un-used
+ * right now.
+ */
+static void __attribute__((unused)) freq_pre_notify_handling(u32 new_freq)
+{
+        struct emif_data *emif;
+
+        /*
+         * NOTE: we are taking the spin-lock here and releases it
+         * only in post-notifier. This doesn't look good and
+         * Sparse complains about it, but this seems to be
+         * un-avoidable. We need to lock a sequence of events
+         * that is split between EMIF and clock framework.
+         *
+         * 1. EMIF driver updates EMIF timings in shadow registers in the
+         *    frequency pre-notify callback from clock framework
+         * 2. clock framework sets up the registers for the new frequency
+         * 3. clock framework initiates a hw-sequence that updates
+         *    the frequency EMIF timings synchronously.
+         *
+         * All these 3 steps should be performed as an atomic operation
+         * vis-a-vis similar sequence in the EMIF interrupt handler
+         * for temperature events. Otherwise, there could be race
+         * conditions that could result in incorrect EMIF timings for
+         * a given frequency
+         */
+        spin_lock_irqsave(&emif_lock, irq_state);
+
+        list_for_each_entry(emif, &device_list, node)
+                do_freq_pre_notify_handling(emif, new_freq);
+}
+
+static void do_freq_post_notify_handling(struct emif_data *emif)
+{
+        /*
+         * Part of workaround for errata i728. See do_freq_update()
+         * for more details
+         */
+        if (emif->lpmode == EMIF_LP_MODE_SELF_REFRESH)
+                set_lpmode(emif, EMIF_LP_MODE_SELF_REFRESH);
+}
+
+/*
+ * TODO: frequency notify handling should be hooked up to
+ * clock framework as soon as the necessary support is
+ * available in mainline kernel. This function is un-used
+ * right now.
+ */
+static void __attribute__((unused)) freq_post_notify_handling(void)
+{
+        struct emif_data *emif;
+
+        list_for_each_entry(emif, &device_list, node)
+                do_freq_post_notify_handling(emif);
+
+        /*
+         * Lock is done in pre-notify handler. See freq_pre_notify_handling()
+         * for more details
+         */
+        spin_unlock_irqrestore(&emif_lock, irq_state);
+}
+
 static struct platform_driver emif_driver = {
         .driver = {
                 .name = "emif",
diff --git a/drivers/memory/emif.h b/drivers/memory/emif.h
index 692b2a864e7b..bfe08bae961a 100644
--- a/drivers/memory/emif.h
+++ b/drivers/memory/emif.h
@@ -19,6 +19,103 @@
  */
 #define EMIF_MAX_NUM_FREQUENCIES                        6
 
+/* State of the core voltage */
+#define DDR_VOLTAGE_STABLE                              0
+#define DDR_VOLTAGE_RAMPING                             1
+
+/* Defines for timing De-rating */
+#define EMIF_NORMAL_TIMINGS                             0
+#define EMIF_DERATED_TIMINGS                            1
+
+/* Length of the forced read idle period in terms of cycles */
+#define EMIF_READ_IDLE_LEN_VAL                          5
+
+/*
+ * forced read idle interval to be used when voltage
+ * is changed as part of DVFS/DPS - 1ms
+ */
+#define READ_IDLE_INTERVAL_DVFS                         (1*1000000)
+
+/*
+ * Forced read idle interval to be used when voltage is stable
+ * 50us - or maximum value will do
+ */
+#define READ_IDLE_INTERVAL_NORMAL                       (50*1000000)
+
+/* DLL calibration interval when voltage is NOT stable - 1us */
+#define DLL_CALIB_INTERVAL_DVFS                         (1*1000000)
+
+#define DLL_CALIB_ACK_WAIT_VAL                          5
+
+/* Interval between ZQCS commands - hw team recommended value */
+#define EMIF_ZQCS_INTERVAL_US                           (50*1000)
+/* Enable ZQ Calibration on exiting Self-refresh */
+#define ZQ_SFEXITEN_ENABLE                              1
+/*
+ * ZQ Calibration simultaneously on both chip-selects:
+ * Needs one calibration resistor per CS
+ */
+#define ZQ_DUALCALEN_DISABLE                            0
+#define ZQ_DUALCALEN_ENABLE                             1
+
+#define T_ZQCS_DEFAULT_NS                               90
+#define T_ZQCL_DEFAULT_NS                               360
+#define T_ZQINIT_DEFAULT_NS                             1000
+
+/* DPD_EN */
+#define DPD_DISABLE                                     0
+#define DPD_ENABLE                                      1
+
+/*
+ * Default values for the low-power entry to be used if not provided by user.
+ * OMAP4/5 has a hw bug(i735) due to which this value can not be less than 512
+ * Timeout values are in DDR clock 'cycles' and frequency threshold in Hz
+ */
+#define EMIF_LP_MODE_TIMEOUT_PERFORMANCE                2048
+#define EMIF_LP_MODE_TIMEOUT_POWER                      512
+#define EMIF_LP_MODE_FREQ_THRESHOLD                     400000000
+
+/* DDR_PHY_CTRL_1 values for EMIF4D - ATTILA PHY combination */
+#define EMIF_DDR_PHY_CTRL_1_BASE_VAL_ATTILAPHY          0x049FF000
+#define EMIF_DLL_SLAVE_DLY_CTRL_400_MHZ_ATTILAPHY       0x41
+#define EMIF_DLL_SLAVE_DLY_CTRL_200_MHZ_ATTILAPHY       0x80
+#define EMIF_DLL_SLAVE_DLY_CTRL_100_MHZ_AND_LESS_ATTILAPHY 0xFF
+
+/* DDR_PHY_CTRL_1 values for EMIF4D5 INTELLIPHY combination */
+#define EMIF_DDR_PHY_CTRL_1_BASE_VAL_INTELLIPHY         0x0E084200
+#define EMIF_PHY_TOTAL_READ_LATENCY_INTELLIPHY_PS       10000
+
+/* TEMP_ALERT_CONFIG - corresponding to temp gradient 5 C/s */
+#define TEMP_ALERT_POLL_INTERVAL_DEFAULT_MS             360
+
+#define EMIF_T_CSTA                                     3
+#define EMIF_T_PDLL_UL                                  128
+
+/* External PHY control registers magic values */
+#define EMIF_EXT_PHY_CTRL_1_VAL                         0x04020080
+#define EMIF_EXT_PHY_CTRL_5_VAL                         0x04010040
+#define EMIF_EXT_PHY_CTRL_6_VAL                         0x01004010
+#define EMIF_EXT_PHY_CTRL_7_VAL                         0x00001004
+#define EMIF_EXT_PHY_CTRL_8_VAL                         0x04010040
+#define EMIF_EXT_PHY_CTRL_9_VAL                         0x01004010
+#define EMIF_EXT_PHY_CTRL_10_VAL                        0x00001004
+#define EMIF_EXT_PHY_CTRL_11_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_12_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_13_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_14_VAL                        0x80080080
+#define EMIF_EXT_PHY_CTRL_15_VAL                        0x00800800
+#define EMIF_EXT_PHY_CTRL_16_VAL                        0x08102040
+#define EMIF_EXT_PHY_CTRL_17_VAL                        0x00000001
+#define EMIF_EXT_PHY_CTRL_18_VAL                        0x540A8150
+#define EMIF_EXT_PHY_CTRL_19_VAL                        0xA81502A0
+#define EMIF_EXT_PHY_CTRL_20_VAL                        0x002A0540
+#define EMIF_EXT_PHY_CTRL_21_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_22_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_23_VAL                        0x00000000
+#define EMIF_EXT_PHY_CTRL_24_VAL                        0x00000077
+
+#define EMIF_INTELLI_PHY_DQS_GATE_OPENING_DELAY_PS      1200
+
 /* Registers offset */
 #define EMIF_MODULE_ID_AND_REVISION                     0x0000
 #define EMIF_STATUS                                     0x0004
@@ -458,4 +555,35 @@
 #define READ_LATENCY_SHDW_SHIFT                         0
 #define READ_LATENCY_SHDW_MASK                          (0x1f << 0)
 
-#endif
+#ifndef __ASSEMBLY__
+/*
+ * Structure containing shadow of important registers in EMIF
+ * The calculation function fills in this structure to be later used for
+ * initialisation and DVFS
+ */
+struct emif_regs {
+        u32 freq;
+        u32 ref_ctrl_shdw;
+        u32 ref_ctrl_shdw_derated;
+        u32 sdram_tim1_shdw;
+        u32 sdram_tim1_shdw_derated;
+        u32 sdram_tim2_shdw;
+        u32 sdram_tim3_shdw;
+        u32 sdram_tim3_shdw_derated;
+        u32 pwr_mgmt_ctrl_shdw;
+        union {
+                u32 read_idle_ctrl_shdw_normal;
+                u32 dll_calib_ctrl_shdw_normal;
+        };
+        union {
+                u32 read_idle_ctrl_shdw_volt_ramp;
+                u32 dll_calib_ctrl_shdw_volt_ramp;
+        };
+
+        u32 phy_ctrl_1_shdw;
+        u32 ext_phy_ctrl_2_shdw;
+        u32 ext_phy_ctrl_3_shdw;
+        u32 ext_phy_ctrl_4_shdw;
+};
+#endif /* __ASSEMBLY__ */
+#endif /* __EMIF_H */