/* SPDX-License-Identifier: GPL-2.0-only */ /* linux/drivers/spi/spi_s3c24xx_fiq.S * * Copyright 2009 Simtec Electronics * Ben Dooks <ben@simtec.co.uk> * * S3C24XX SPI - FIQ pseudo-DMA transfer code */ #include <linux/linkage.h> #include <asm/assembler.h> #include <mach/map.h> #include <mach/regs-irq.h> #include <plat/regs-spi.h> #include "spi-s3c24xx-fiq.h" .text @ entry to these routines is as follows, with the register names @ defined in fiq.h so that they can be shared with the C files which @ setup the calling registers. @ @ fiq_rirq The base of the IRQ registers to find S3C2410_SRCPND @ fiq_rtmp Temporary register to hold tx/rx data @ fiq_rspi The base of the SPI register block @ fiq_rtx The tx buffer pointer @ fiq_rrx The rx buffer pointer @ fiq_rcount The number of bytes to move @ each entry starts with a word entry of how long it is @ and an offset to the irq acknowledgment word ENTRY(s3c24xx_spi_fiq_rx) s3c24xx_spi_fix_rx: .word fiq_rx_end - fiq_rx_start .word fiq_rx_irq_ack - fiq_rx_start fiq_rx_start: ldr fiq_rtmp, fiq_rx_irq_ack str fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ] ldrb fiq_rtmp, [ fiq_rspi, # S3C2410_SPRDAT ] strb fiq_rtmp, [ fiq_rrx ], #1 mov fiq_rtmp, #0xff strb fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ] subs fiq_rcount, fiq_rcount, #1 subnes pc, lr, #4 @@ return, still have work to do @@ set IRQ controller so that next op will trigger IRQ mov fiq_rtmp, #0 str fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD - S3C24XX_VA_IRQ ] subs pc, lr, #4 fiq_rx_irq_ack: .word 0 fiq_rx_end: ENTRY(s3c24xx_spi_fiq_txrx) s3c24xx_spi_fiq_txrx: .word fiq_txrx_end - fiq_txrx_start .word fiq_txrx_irq_ack - fiq_txrx_start fiq_txrx_start: ldrb fiq_rtmp, [ fiq_rspi, # S3C2410_SPRDAT ] strb fiq_rtmp, [ fiq_rrx ], #1 ldr fiq_rtmp, fiq_txrx_irq_ack str fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ] ldrb fiq_rtmp, [ fiq_rtx ], #1 strb fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ] subs fiq_rcount, fiq_rcount, #1 subnes pc, lr, #4 @@ return, still have work to do mov fiq_rtmp, #0 str fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD - S3C24XX_VA_IRQ ] subs pc, lr, #4 fiq_txrx_irq_ack: .word 0 fiq_txrx_end: ENTRY(s3c24xx_spi_fiq_tx) s3c24xx_spi_fix_tx: .word fiq_tx_end - fiq_tx_start .word fiq_tx_irq_ack - fiq_tx_start fiq_tx_start: ldrb fiq_rtmp, [ fiq_rspi, # S3C2410_SPRDAT ] ldr fiq_rtmp, fiq_tx_irq_ack str fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ] ldrb fiq_rtmp, [ fiq_rtx ], #1 strb fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ] subs fiq_rcount, fiq_rcount, #1 subnes pc, lr, #4 @@ return, still have work to do mov fiq_rtmp, #0 str fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD - S3C24XX_VA_IRQ ] subs pc, lr, #4 fiq_tx_irq_ack: .word 0 fiq_tx_end: .end