memory: emif: errata i743: Prohibit usage of Power-Down mode

	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) &&

	    (EMIF_LP_MODE_PWR_DN == lpmode)) {

		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);