114 lines
3.0 KiB
Plaintext
114 lines
3.0 KiB
Plaintext
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* Freescale Smart Direct Memory Access (SDMA) Controller for i.MX
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Required properties:
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- compatible : Should be one of
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"fsl,imx25-sdma"
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"fsl,imx31-sdma", "fsl,imx31-to1-sdma", "fsl,imx31-to2-sdma"
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"fsl,imx35-sdma", "fsl,imx35-to1-sdma", "fsl,imx35-to2-sdma"
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"fsl,imx51-sdma"
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"fsl,imx53-sdma"
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"fsl,imx6q-sdma"
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"fsl,imx7d-sdma"
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The -to variants should be preferred since they allow to determine the
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correct ROM script addresses needed for the driver to work without additional
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firmware.
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- reg : Should contain SDMA registers location and length
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- interrupts : Should contain SDMA interrupt
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- #dma-cells : Must be <3>.
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The first cell specifies the DMA request/event ID. See details below
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about the second and third cell.
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- fsl,sdma-ram-script-name : Should contain the full path of SDMA RAM
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scripts firmware
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The second cell of dma phandle specifies the peripheral type of DMA transfer.
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The full ID of peripheral types can be found below.
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ID transfer type
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---------------------
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0 MCU domain SSI
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1 Shared SSI
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2 MMC
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3 SDHC
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4 MCU domain UART
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5 Shared UART
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6 FIRI
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7 MCU domain CSPI
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8 Shared CSPI
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9 SIM
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10 ATA
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11 CCM
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12 External peripheral
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13 Memory Stick Host Controller
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14 Shared Memory Stick Host Controller
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15 DSP
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16 Memory
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17 FIFO type Memory
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18 SPDIF
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19 IPU Memory
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20 ASRC
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21 ESAI
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22 SSI Dual FIFO (needs firmware ver >= 2)
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23 Shared ASRC
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24 SAI
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The third cell specifies the transfer priority as below.
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ID transfer priority
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-------------------------
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0 High
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1 Medium
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2 Low
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Optional properties:
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- gpr : The phandle to the General Purpose Register (GPR) node.
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- fsl,sdma-event-remap : Register bits of sdma event remap, the format is
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<reg shift val>.
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reg is the GPR register offset.
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shift is the bit position inside the GPR register.
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val is the value of the bit (0 or 1).
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Examples:
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sdma@83fb0000 {
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compatible = "fsl,imx51-sdma", "fsl,imx35-sdma";
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reg = <0x83fb0000 0x4000>;
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interrupts = <6>;
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#dma-cells = <3>;
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fsl,sdma-ram-script-name = "sdma-imx51.bin";
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};
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DMA clients connected to the i.MX SDMA controller must use the format
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described in the dma.txt file.
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Examples:
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ssi2: ssi@70014000 {
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compatible = "fsl,imx51-ssi", "fsl,imx21-ssi";
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reg = <0x70014000 0x4000>;
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interrupts = <30>;
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clocks = <&clks 49>;
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dmas = <&sdma 24 1 0>,
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<&sdma 25 1 0>;
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dma-names = "rx", "tx";
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fsl,fifo-depth = <15>;
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};
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Using the fsl,sdma-event-remap property:
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If we want to use SDMA on the SAI1 port on a MX6SX:
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&sdma {
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gpr = <&gpr>;
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/* SDMA events remap for SAI1_RX and SAI1_TX */
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fsl,sdma-event-remap = <0 15 1>, <0 16 1>;
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};
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The fsl,sdma-event-remap property in this case has two values:
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- <0 15 1> means that the offset is 0, so GPR0 is the register of the
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SDMA remap. Bit 15 of GPR0 selects between UART4_RX and SAI1_RX.
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Setting bit 15 to 1 selects SAI1_RX.
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- <0 16 1> means that the offset is 0, so GPR0 is the register of the
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SDMA remap. Bit 16 of GPR0 selects between UART4_TX and SAI1_TX.
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Setting bit 16 to 1 selects SAI1_TX.
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