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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: LPDDR2 SDRAM compliant to JEDEC JESD209-2
maintainers:
- Krzysztof Kozlowski <krzk@kernel.org>
properties:
compatible:
oneOf:
- items:
- enum:
- elpida,ECB240ABACN
- elpida,B8132B2PB-6D-F
- enum:
- jedec,lpddr2-s4
- items:
- enum:
- jedec,lpddr2-s2
- items:
- enum:
- jedec,lpddr2-nvm
revision-id1:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 255
description: |
Revision 1 value of SDRAM chip. Obtained from device datasheet.
Property is deprecated, use revision-id instead.
deprecated: true
revision-id2:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 255
description: |
Revision 2 value of SDRAM chip. Obtained from device datasheet.
Property is deprecated, use revision-id instead.
deprecated: true
revision-id:
$ref: /schemas/types.yaml#/definitions/uint32-array
description: |
Revision IDs read from Mode Register 6 and 7. One byte per uint32 cell (i.e. <MR6 MR7>).
minItems: 2
maxItems: 2
items:
minimum: 0
maximum: 255
density:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Density in megabits of SDRAM chip. Obtained from device datasheet.
enum:
- 64
- 128
- 256
- 512
- 1024
- 2048
- 4096
- 8192
- 16384
- 32768
io-width:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
IO bus width in bits of SDRAM chip. Obtained from device datasheet.
enum:
- 32
- 16
- 8
tRRD-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Active bank a to active bank b in terms of number of clock cycles.
Obtained from device datasheet.
tWTR-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Internal WRITE-to-READ command delay in terms of number of clock cycles.
Obtained from device datasheet.
tXP-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Exit power-down to next valid command delay in terms of number of clock
cycles. Obtained from device datasheet.
tRTP-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Internal READ to PRECHARGE command delay in terms of number of clock
cycles. Obtained from device datasheet.
tCKE-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
CKE minimum pulse width (HIGH and LOW pulse width) in terms of number
of clock cycles. Obtained from device datasheet.
tRPab-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Row precharge time (all banks) in terms of number of clock cycles.
Obtained from device datasheet.
tRCD-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
RAS-to-CAS delay in terms of number of clock cycles. Obtained from
device datasheet.
tWR-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
WRITE recovery time in terms of number of clock cycles. Obtained from
device datasheet.
tRASmin-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Row active time in terms of number of clock cycles. Obtained from device
datasheet.
tCKESR-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
CKE minimum pulse width during SELF REFRESH (low pulse width during
SELF REFRESH) in terms of number of clock cycles. Obtained from device
datasheet.
tFAW-min-tck:
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 16
description: |
Four-bank activate window in terms of number of clock cycles. Obtained
from device datasheet.
patternProperties:
"^lpddr2-timings":
$ref: jedec,lpddr2-timings.yaml
description: |
The lpddr2 node may have one or more child nodes of type "lpddr2-timings".
"lpddr2-timings" provides AC timing parameters of the device for
a given speed-bin. The user may provide the timings for as many
speed-bins as is required.
required:
- compatible
- density
- io-width
additionalProperties: false
examples:
- |
elpida_ECB240ABACN: lpddr2 {
compatible = "elpida,ECB240ABACN", "jedec,lpddr2-s4";
density = <2048>;
io-width = <32>;
revision-id = <1 0>;
tRPab-min-tck = <3>;
tRCD-min-tck = <3>;
tWR-min-tck = <3>;
tRASmin-min-tck = <3>;
tRRD-min-tck = <2>;
tWTR-min-tck = <2>;
tXP-min-tck = <2>;
tRTP-min-tck = <2>;
tCKE-min-tck = <3>;
tCKESR-min-tck = <3>;
tFAW-min-tck = <8>;
timings_elpida_ECB240ABACN_400mhz: lpddr2-timings0 {
compatible = "jedec,lpddr2-timings";
min-freq = <10000000>;
max-freq = <400000000>;
tRPab = <21000>;
tRCD = <18000>;
tWR = <15000>;
tRAS-min = <42000>;
tRRD = <10000>;
tWTR = <7500>;
tXP = <7500>;
tRTP = <7500>;
tCKESR = <15000>;
tDQSCK-max = <5500>;
tFAW = <50000>;
tZQCS = <90000>;
tZQCL = <360000>;
tZQinit = <1000000>;
tRAS-max-ns = <70000>;
};
timings_elpida_ECB240ABACN_200mhz: lpddr2-timings1 {
compatible = "jedec,lpddr2-timings";
min-freq = <10000000>;
max-freq = <200000000>;
tRPab = <21000>;
tRCD = <18000>;
tWR = <15000>;
tRAS-min = <42000>;
tRRD = <10000>;
tWTR = <10000>;
tXP = <7500>;
tRTP = <7500>;
tCKESR = <15000>;
tDQSCK-max = <5500>;
tFAW = <50000>;
tZQCS = <90000>;
tZQCL = <360000>;
tZQinit = <1000000>;
tRAS-max-ns = <70000>;
};
};
|
