Add Loongson-2K0300 APB DMA mux support
Subsystems (3)
v3 cover Add Loongson-2K0300 APB DMA mux support
Hi all:
Loongson-2K0300 integrates a CMC DMA controller with 8 physical channels. Peripheral DMA requests are not hard-wired to these channels; they are routed through the CHIP_CTRL13/14/15 DMA_MAP fields.
This series adds support for that DMA request router.
Patch 1 adds the DT binding constants for the peripheral request IDs and yaml file for the DMA mux.
Patch 2 adds the driver, Kconfig symbol and Makefile entry.
The driver registers with of_dma_router_register(). In the route allocation callback it validates the <request> <channel> <flags> specifier, programs the SoC-specific route register, and forwards <channel> <flags> to the parent CMC DMA controller.
Thanks.
Binbin.
=========
V3:
Patch(1/2):
- Merged the two commits containing the dt-binding header file and the YAML file; no other changes were made;
- Add Acked-by tag from Conor.
Patch(2/2):
- Append the dmamux object to the existing CMC DMA line;
- Add loongson2_dmamux_assign_bits() helper, no functional change;
- Add Reviewed-by tag from Frank.
Link to V2:
https://lore.kernel.org/all/[email protected]/
V2:
Patch(1/3):
- Drop LS2K0300_DMA_REQ_MAX as it is not part of the ABI;
Patch(2/3):
- A more detailed description of dma-cells;
- Add the dma_requests constraint
Patch(3/3):
- Drop loongson2_dmamux_map->shift;
- Move of_parse_phandle() into loongson2_dmamux_route_allocate() avoid UAF;
- Drop loongson2_dmamux->dma_np;
- Check dma_requests;
- Add devm_add_action_or_reset() instead of .remove();
- Replace metux() with spinlock(), which has lower overhead;
- Add loongson2_dmamux_route_free().
Link to V1:
https://lore.kernel.org/all/[email protected]/
Binbin Zhou (2):
dt-bindings: dma: Document DMA mux support for Loongson-2K0300
dmaengine: loongson: Add Loongson-2K0300 APB DMA mux driver
.../dma/loongson,ls2k0300-dmamux.yaml | 72 ++++ MAINTAINERS | 3 + drivers/dma/loongson/Makefile | 2 +- drivers/dma/loongson/loongson2-apb-dmamux.c | 404 ++++++++++++++++++ .../dt-bindings/dma/loongson,ls2k-dmamux.h | 53 +++ 5 files changed, 533 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml create mode 100644 drivers/dma/loongson/loongson2-apb-dmamux.c create mode 100644 include/dt-bindings/dma/loongson,ls2k-dmamux.h
base-commit: aff5e6a77fc69a7c490246465940d18422d7c631
Signature · 1 line
2.52.0
PATCH v3 1/2 dt-bindings: dma: Document DMA mux support for Loongson-2K0300
The DMA mux on Loongson-2K0300 is not a standalone hardware block. It is implemented as part of the chip configuration registers CHIP_CTRL13/14/15, which route peripheral DMA requests to the physical channels of the CMC DMA controller.
Document this as a DMA router. The #dma-cells = <3> specifier contains the peripheral request ID, the target CMC DMA channel, and channel configuration flags forwarded to the parent DMA controller.
--- .../dma/loongson,ls2k0300-dmamux.yaml | 72 +++++++++++++++++++ MAINTAINERS | 2 + .../dt-bindings/dma/loongson,ls2k-dmamux.h | 53 ++++++++++++++ 3 files changed, 127 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml create mode 100644 include/dt-bindings/dma/loongson,ls2k-dmamux.h
Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml new file +72 -0
@@ -0,0 +1,72 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dma/loongson,ls2k0300-dmamux.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Loongson-2 APB DMA MUX (DMA request router) + +maintainers: + - Binbin Zhou <[email protected]> + +allOf: + - $ref: /schemas/dma/dma-router.yaml# + +properties: + compatible: + const: loongson,ls2k0300-dmamux + + reg: + maxItems: 1 + + '#dma-cells': + const: 3 + description: | + Each cell represents the following: + 1. Peripheral request ID: This describes the corresponding bit field + for that peripheral in the configuration register; see ( + include/dt-bindings/dma/loongson,ls2k-dmamux.h) for details. + 2. Physical DMA channel (0-7): This not only represents the DMA + channel used by the peripheral but is also converted into a value for + the corresponding bit field in the configuration register, indicating + the legitimacy of that peripheral using that channel. + Specifically: + - I2S/SPI/UART/I2C: Require adjacent channels in pairs; valid + values are 0/1, 2/3, 4/5, 6/7; + - SM3/SM4/DES/AES: Single channel; valid values are limited to 0/1; + - CAN/ADC: Single channel; valid values range from 0 to 7. + 3. DMA Channel Configuration: A 32-bit mask used to specify + device-specific DMA channel configurations. + - Bit 6: Peripheral Address Increment Mode + 0x0: Disabled + 0x1: Enabled + - Bit 7: Memory Address Increment Mode + 0x0: Disabled + 0x1: Enabled + - Bits 12-13: Priority + 0x0: Low + 0x1: Medium + 0x2: High + 0x3: Very High + + dma-requests: + const: 22 + +required: + - compatible + - reg + - dma-requests + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/dma/loongson,ls2k-dmamux.h> + dma-router@16000134 { + compatible = "loongson,ls2k0300-dmamux"; + reg = <0x16000134 0xc>; + #dma-cells = <3>; + dma-masters = <&dma>; + dma-requests = <22>; + }; +...
MAINTAINERS +2 -0
@@ -15351,9 +15351,11 @@ M: Binbin Zhou <[email protected]> L: [email protected] S: Maintained F: Documentation/devicetree/bindings/dma/loongson,ls2k0300-dma.yaml +F: Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml F: Documentation/devicetree/bindings/dma/loongson,ls2x-apbdma.yaml F: drivers/dma/loongson/loongson2-apb-cmc-dma.c F: drivers/dma/loongson/loongson2-apb-dma.c +F: include/dt-bindings/dma/loongson,ls2k-dmamux.h LOONGSON LS2X I2C DRIVER M: Binbin Zhou <[email protected]>
include/dt-bindings/dma/loongson,ls2k-dmamux.h new file +53 -0
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Signature · 1 line
2.52.0
Re: [PATCH v3 1/2] dt-bindings: dma: Document DMA mux support for Loongson-2K0300
Quoted 5 lines · Binbin Zhou
The DMA mux on Loongson-2K0300 is not a standalone hardware block. It is implemented as part of the chip configuration registers CHIP_CTRL13/14/15, which route peripheral DMA requests to the physical channels of the CMC DMA controller.
Quoted 7 lines
Document this as a DMA router. The #dma-cells = <3> specifier contains the peripheral request ID, the target CMC DMA channel, and channel configuration flags forwarded to the parent DMA controller.
Acked-by Conor Dooley <[email protected]>Signed-off-by Binbin Zhou <[email protected]>---
Quoted 163 lines
.../dma/loongson,ls2k0300-dmamux.yaml | 72 +++++++++++++++++++ MAINTAINERS | 2 + .../dt-bindings/dma/loongson,ls2k-dmamux.h | 53 ++++++++++++++ 3 files changed, 127 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml create mode 100644 include/dt-bindings/dma/loongson,ls2k-dmamux.hDocumentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml new file +72
-0@@ -0,0 +1,72 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dma/loongson,ls2k0300-dmamux.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Loongson-2 APB DMA MUX (DMA request router) + +maintainers: + - Binbin Zhou <[email protected]> + +allOf: + - $ref: /schemas/dma/dma-router.yaml# + +properties: + compatible: + const: loongson,ls2k0300-dmamux + + reg: + maxItems: 1 + + '#dma-cells': + const: 3 + description: | + Each cell represents the following: + 1. Peripheral request ID: This describes the corresponding bit field + for that peripheral in the configuration register; see ( + include/dt-bindings/dma/loongson,ls2k-dmamux.h) for details. + 2. Physical DMA channel (0-7): This not only represents the DMA + channel used by the peripheral but is also converted into a value for + the corresponding bit field in the configuration register, indicating + the legitimacy of that peripheral using that channel. + Specifically: + - I2S/SPI/UART/I2C: Require adjacent channels in pairs; valid + values are 0/1, 2/3, 4/5, 6/7; + - SM3/SM4/DES/AES: Single channel; valid values are limited to 0/1; + - CAN/ADC: Single channel; valid values range from 0 to 7. + 3. DMA Channel Configuration: A 32-bit mask used to specify + device-specific DMA channel configurations. + - Bit 6: Peripheral Address Increment Mode + 0x0: Disabled + 0x1: Enabled + - Bit 7: Memory Address Increment Mode + 0x0: Disabled + 0x1: Enabled + - Bits 12-13: Priority + 0x0: Low + 0x1: Medium + 0x2: High + 0x3: Very High + + dma-requests: + const: 22 + +required: + - compatible + - reg + - dma-requests + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/dma/loongson,ls2k-dmamux.h> + dma-router@16000134 { + compatible = "loongson,ls2k0300-dmamux"; + reg = <0x16000134 0xc>; + #dma-cells = <3>; + dma-masters = <&dma>; + dma-requests = <22>; + }; +...MAINTAINERS +2
-0@@ -15351,9 +15351,11 @@ M: Binbin Zhou <[email protected]> L: [email protected] S: Maintained F: Documentation/devicetree/bindings/dma/loongson,ls2k0300-dma.yaml +F: Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml F: Documentation/devicetree/bindings/dma/loongson,ls2x-apbdma.yaml F: drivers/dma/loongson/loongson2-apb-cmc-dma.c F: drivers/dma/loongson/loongson2-apb-dma.c +F: include/dt-bindings/dma/loongson,ls2k-dmamux.h LOONGSON LS2X I2C DRIVER M: Binbin Zhou <[email protected]>include/dt-bindings/dma/loongson,ls2k-dmamux.h new file +53
-1@@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */ +/* +* Loongson-2 SoC DMA Mux dt-bindings +* +* DMA specifier format: +* dmas = <&dma_mux <request> <channel> <flags>>; +* +* The <channel> cell selects a physical CMC DMA channel (0-7) +* For peripherals using channel pairs (UART, I2C, SPI2/3, I2S), +* the channel number selects the pair: 0/1 -> pair 0, 2/3 -> pair 1, +* 4/5 -> pair 2, 6/7 -> pair 3. +* +* Copyright (C) 2026 Loongson Technology Corporation Limited +*/ + +#ifndef _DT_BINDINGS_DMA_LOONGSON_LS2K_DMAMUX_H +#define _DT_BINDINGS_DMA_LOONGSON_LS2K_DMAMUX_H + +/* UART controllers */ +#define LS2K0300_DMA_UART0 0 +#define LS2K0300_DMA_UART1 1 +#define LS2K0300_DMA_UART2 2 +#define LS2K0300_DMA_UART3 3 +#define LS2K0300_DMA_UART4 4 +#define LS2K0300_DMA_UART5 5 +#define LS2K0300_DMA_UART6 6 +#define LS2K0300_DMA_UART7 7 +#define LS2K0300_DMA_UART8 8 +#define LS2K0300_DMA_UART9 9 + +/* I2C controllers */ +#define LS2K0300_DMA_I2C0 10 +#define LS2K0300_DMA_I2C1 11 +#define LS2K0300_DMA_I2C2 12 +#define LS2K0300_DMA_I2C3 13 + +/* SPI controllers (IO mode) */ +#define LS2K0300_DMA_SPI2 14 +#define LS2K0300_DMA_SPI3 15 + +/* I2S controller */ +#define LS2K0300_DMA_I2S 16 + +/* ADC controller */ +#define LS2K0300_DMA_ADC 17 + +/* CAN-FD controllers */ +#define LS2K0300_DMA_CAN0 18 +#define LS2K0300_DMA_CAN1 19 +#define LS2K0300_DMA_CAN2 20 +#define LS2K0300_DMA_CAN3 21 + +#endif /* _DT_BINDINGS_DMA_LOONGSON_LS2K_DMAMUX_H */ --2.52.0
PATCH v3 2/2 dmaengine: loongson: Add Loongson-2K0300 APB DMA mux driver
In reply to Binbin ZhouThe Loongson-2K0300 DMA mux is not a standalone DMA controller. It is implemented as a set of routing fields in the chip global configuration registers CHIP_CTRL13/14/15, which select which physical channel of the on-chip CMC DMA controller handles each peripheral DMA request.
Add a driver that exposes these routing fields as an OF DMA router. The router's allocation callback validates the <request> <channel> <flags> specifier, programs the corresponding CHIP_CTRL register field, and then rewrites the specifier to <channel> <flags> so that the parent CMC DMA controller's xlate is used.
--- MAINTAINERS | 1 + drivers/dma/loongson/Makefile | 2 +- drivers/dma/loongson/loongson2-apb-dmamux.c | 404 ++++++++++++++++++++ 3 files changed, 406 insertions(+), 1 deletion(-) create mode 100644 drivers/dma/loongson/loongson2-apb-dmamux.c
MAINTAINERS +1 -0
@@ -15355,6 +15355,7 @@ F: Documentation/devicetree/bindings/dma/loongson,ls2k0300-dmamux.yaml F: Documentation/devicetree/bindings/dma/loongson,ls2x-apbdma.yaml F: drivers/dma/loongson/loongson2-apb-cmc-dma.c F: drivers/dma/loongson/loongson2-apb-dma.c +F: drivers/dma/loongson/loongson2-apb-dmamux.c F: include/dt-bindings/dma/loongson,ls2k-dmamux.h LOONGSON LS2X I2C DRIVER
drivers/dma/loongson/Makefile +1 -1
@@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-$(CONFIG_LOONGSON1_APB_DMA) += loongson1-apb-dma.o obj-$(CONFIG_LOONGSON2_APB_DMA) += loongson2-apb-dma.o -obj-$(CONFIG_LOONGSON2_APB_CMC_DMA) += loongson2-apb-cmc-dma.o +obj-$(CONFIG_LOONGSON2_APB_CMC_DMA) += loongson2-apb-cmc-dma.o loongson2-apb-dmamux.o
drivers/dma/loongson/loongson2-apb-dmamux.c new file +404 -0
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2.52.0