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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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8051effcbc
This patch is V2 of SPI Master support for the SuperH MSIOF. Full duplex, spi mode 0-3, active high cs, 3-wire and lsb first should all be supported, but the driver has so far only been tested with "mmc_spi". The MSIOF hardware comes with 32-bit FIFOs for receive and transmit, and this driver simply breaks the SPI messages into FIFO-sized chunks. The MSIOF hardware manages the pins for clock, receive and transmit (sck/miso/mosi), but the chip select pin is managed by software and must be configured as a regular GPIO pin by the board code. Performance wise there is still room for improvement, but on a Ecovec board with the built-in sh7724 MSIOF0 this driver gets Mini-sd read speeds of about half a megabyte per second. Future work include better clock setup and merging of 8-bit transfers into 32-bit words to reduce interrupt load and improve throughput. Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
11 lines
185 B
C
11 lines
185 B
C
#ifndef __SPI_SH_MSIOF_H__
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#define __SPI_SH_MSIOF_H__
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struct sh_msiof_spi_info {
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int tx_fifo_override;
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int rx_fifo_override;
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u16 num_chipselect;
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};
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#endif /* __SPI_SH_MSIOF_H__ */
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