84 lines
1.9 KiB
Markdown
84 lines
1.9 KiB
Markdown
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!!! notice
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***Preliminary Info***
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RK3399 has SPI controller with following features:
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- 6 on-chip SPI controllers
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- Support master and slave mode, software-configurable
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- DMA-based or interrupt-based operation
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- Embedded two 32x16bits FIFO for TX and RX operation respectively
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On Helios64 the bus are divided into three types: unused, system (internal bus) and user application (external)
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| Bus | Usage | Remarks |
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|-----|-------|-----------|
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| 0 | Not Used | |
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| 1 | System | Bootable SPI Flash |
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| 2 | External | User Application |
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| 3 | Not Used | |
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| 4 | Not Used | |
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| 5 | System | Reserved for Production use only |
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## Internal Bus
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| Bus | Chip Select | Device | Remarks |
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|-----|-------------|---------|---------|
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| 1 | 0 | W25Q128JV | Bootable SPI Flash |
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| 5 | 0 | W25X20CL | SATA Controller ROM |
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### Bootable SPI Flash
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Helios64 is equipped with [Winbond W25Q128JV 3V 128M-Bit Serial Flash Memory](https://www.winbond.com/hq/product/code-storage-flash-memory/serial-nor-flash/?__locale=en&partNo=W25Q128JV)
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as a Bootable SPI NOR Flash.
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This flash contains
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- preloader & bootloader
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| Binaries | Offset | Remarks |
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|----------|--------|---------|
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| Preloader | 0x0040 | U-Boot TPL & SPL |
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| Bootloader | 0x4000 | U-Boot & ATF |
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- electronic nameplate data in Security Register
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## External Bus
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| Bus | Chip Select | Remarks |
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|-----|-------------|---------|
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| 2 | 0 | User Application |
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SPI Bus for user application is exposed on [UEXT Connector (P2)](/helios64/uext)
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| Pin | Signal Name |
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|-----|-------------|
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| 7 | MISO |
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| 8 | MOSI |
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| 9 | SCK |
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| 10 | SSEL |
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The pin voltage level is 3.3V
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## Usage in Linux
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### Enable SPIDEV in device tree
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To make SPI device accessible by user space application, we need to create a device tree node.
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After the node has been created, user application can access the device at
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`/dev/spidev5.0`
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!!! note
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*To Be Updated*
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