Commit d25abd9d authored by Nancy Chen's avatar Nancy Chen

ENGR00220989 [MX6SL]: DDR Controller measure unit workaround

[MX6SL]MMDC: DDR Controller's measure unit may return an incorrect
value when operating below 100 MHz
Signed-off-by: default avatarNancy Chen <>
parent 2a1c7b7e
......@@ -204,6 +204,42 @@ mmdc_podf1:
.macro mmdc_clk_lower_100MHz
/* Prior to reducing the DDR frequency (at 528/400 MHz),
read the Measure unit count bits (MU_UNIT_DEL_NUM) */
ldr r5, =0x8B8
ldr r6, [r8, r5]
/* Original MU unit count */
mov r6, r6, LSR #16
ldr r4, =0x3FF
and r6, r6, r4
/* Original MU unit count * 2 */
mov r1, r6, LSL #1
/* Bypass the automatic measure unit when below 100 MHz
by setting the Measure unit bypass enable bit (MU_BYP_EN) */
ldr r6, [r8, r5]
orr r6, r6, #0x400
str r6, [r8, r5]
/* Double the measure count value read in step 1 and program it in the
measurement bypass bits (MU_BYP_VAL) of the MMDC PHY Measure Unit
Register for the reduced frequency operation below 100 MHz */
ldr r6, [r8, r5]
ldr r4, =0x3FF
bic r6, r6, r4
orr r6, r6, r1
str r6, [r8, r5]
.macro mmdc_clk_above_100MHz
/* Make sure that the PHY measurement unit is NOT in bypass mode */
ldr r5, =0x8B8
ldr r6, [r8, r5]
bic r6, r6, #0x400
str r6, [r8, r5]
* mx6sl_ddr_iram
......@@ -281,10 +317,12 @@ poll_dvfs_set_1:
cmp r0, r1
beq set_to_24MHz
b done
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