diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 7 | ||||
| -rw-r--r-- | drivers/spi/spi_s3c24xx.c | 244 | ||||
| -rw-r--r-- | drivers/spi/spi_s3c24xx_fiq.S | 116 | ||||
| -rw-r--r-- | drivers/spi/spi_s3c24xx_fiq.h | 26 |
5 files changed, 390 insertions, 14 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index d7c1741c4c5b..6fa595e0c989 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -219,6 +219,17 @@ config SPI_S3C24XX help SPI driver for Samsung S3C24XX series ARM SoCs +config SPI_S3C24XX_FIQ + bool "S3C24XX driver with FIQ pseudo-DMA" + depends on SPI_S3C24XX + select FIQ + help + Enable FIQ support for the S3C24XX SPI driver to provide pseudo + DMA by using the fast-interrupt request framework, This allows + the driver to get DMA-like performance when there are either + no free DMA channels, or when doing transfers that required both + TX and RX data paths. + config SPI_S3C24XX_GPIO tristate "Samsung S3C24XX series SPI by GPIO" depends on ARCH_S3C2410 && EXPERIMENTAL diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index a909e39f7e7c..33faa7fa0ab8 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -32,7 +32,7 @@ obj-$(CONFIG_SPI_MPC52xx) += mpc52xx_spi.o obj-$(CONFIG_SPI_MPC8xxx) += spi_mpc8xxx.o obj-$(CONFIG_SPI_PPC4xx) += spi_ppc4xx.o obj-$(CONFIG_SPI_S3C24XX_GPIO) += spi_s3c24xx_gpio.o -obj-$(CONFIG_SPI_S3C24XX) += spi_s3c24xx.o +obj-$(CONFIG_SPI_S3C24XX) += spi_s3c24xx_hw.o obj-$(CONFIG_SPI_TXX9) += spi_txx9.o obj-$(CONFIG_SPI_XILINX) += xilinx_spi.o obj-$(CONFIG_SPI_XILINX_OF) += xilinx_spi_of.o @@ -41,6 +41,11 @@ obj-$(CONFIG_SPI_SH_SCI) += spi_sh_sci.o obj-$(CONFIG_SPI_SH_MSIOF) += spi_sh_msiof.o obj-$(CONFIG_SPI_STMP3XXX) += spi_stmp.o obj-$(CONFIG_SPI_NUC900) += spi_nuc900.o + +# special build for s3c24xx spi driver with fiq support +spi_s3c24xx_hw-y := spi_s3c24xx.o +spi_s3c24xx_hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi_s3c24xx_fiq.o + # ... add above this line ... # SPI protocol drivers (device/link on bus) diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c index 33d94f76b9ef..4b0d25b497ac 100644 --- a/drivers/spi/spi_s3c24xx.c +++ b/drivers/spi/spi_s3c24xx.c @@ -1,7 +1,7 @@ /* linux/drivers/spi/spi_s3c24xx.c * * Copyright (c) 2006 Ben Dooks - * Copyright (c) 2006 Simtec Electronics + * Copyright 2006-2009 Simtec Electronics * Ben Dooks <ben@simtec.co.uk> * * This program is free software; you can redistribute it and/or modify @@ -28,6 +28,11 @@ #include <plat/regs-spi.h> #include <mach/spi.h> +#include <plat/fiq.h> +#include <asm/fiq.h> + +#include "spi_s3c24xx_fiq.h" + /** * s3c24xx_spi_devstate - per device data * @hz: Last frequency calculated for @sppre field. @@ -42,6 +47,13 @@ struct s3c24xx_spi_devstate { u8 sppre; }; +enum spi_fiq_mode { + FIQ_MODE_NONE = 0, + FIQ_MODE_TX = 1, + FIQ_MODE_RX = 2, + FIQ_MODE_TXRX = 3, +}; + struct s3c24xx_spi { /* bitbang has to be first */ struct spi_bitbang bitbang; @@ -52,6 +64,11 @@ struct s3c24xx_spi { int len; int count; + struct fiq_handler fiq_handler; + enum spi_fiq_mode fiq_mode; + unsigned char fiq_inuse; + unsigned char fiq_claimed; + void (*set_cs)(struct s3c2410_spi_info *spi, int cs, int pol); @@ -67,6 +84,7 @@ struct s3c24xx_spi { struct s3c2410_spi_info *pdata; }; + #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT) #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP) @@ -127,7 +145,7 @@ static int s3c24xx_spi_update_state(struct spi_device *spi, } if (spi->mode != cs->mode) { - u8 spcon = SPCON_DEFAULT; + u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK; if (spi->mode & SPI_CPHA) spcon |= S3C2410_SPCON_CPHA_FMTB; @@ -214,13 +232,196 @@ static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count) return hw->tx ? hw->tx[count] : 0; } +#ifdef CONFIG_SPI_S3C24XX_FIQ +/* Support for FIQ based pseudo-DMA to improve the transfer speed. + * + * This code uses the assembly helper in spi_s3c24xx_spi.S which is + * used by the FIQ core to move data between main memory and the peripheral + * block. Since this is code running on the processor, there is no problem + * with cache coherency of the buffers, so we can use any buffer we like. + */ + +/** + * struct spi_fiq_code - FIQ code and header + * @length: The length of the code fragment, excluding this header. + * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at. + * @data: The code itself to install as a FIQ handler. + */ +struct spi_fiq_code { + u32 length; + u32 ack_offset; + u8 data[0]; +}; + +extern struct spi_fiq_code s3c24xx_spi_fiq_txrx; +extern struct spi_fiq_code s3c24xx_spi_fiq_tx; +extern struct spi_fiq_code s3c24xx_spi_fiq_rx; + +/** + * ack_bit - turn IRQ into IRQ acknowledgement bit + * @irq: The interrupt number + * + * Returns the bit to write to the interrupt acknowledge register. + */ +static inline u32 ack_bit(unsigned int irq) +{ + return 1 << (irq - IRQ_EINT0); +} + +/** + * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer + * @hw: The hardware state. + * + * Claim the FIQ handler (only one can be active at any one time) and + * then setup the correct transfer code for this transfer. + * + * This call updates all the necessary state information if sucessful, + * so the caller does not need to do anything more than start the transfer + * as normal, since the IRQ will have been re-routed to the FIQ handler. +*/ +void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw) +{ + struct pt_regs regs; + enum spi_fiq_mode mode; + struct spi_fiq_code *code; + int ret; + + if (!hw->fiq_claimed) { + /* try and claim fiq if we haven't got it, and if not + * then return and simply use another transfer method */ + + ret = claim_fiq(&hw->fiq_handler); + if (ret) + return; + } + + if (hw->tx && !hw->rx) + mode = FIQ_MODE_TX; + else if (hw->rx && !hw->tx) + mode = FIQ_MODE_RX; + else + mode = FIQ_MODE_TXRX; + + regs.uregs[fiq_rspi] = (long)hw->regs; + regs.uregs[fiq_rrx] = (long)hw->rx; + regs.uregs[fiq_rtx] = (long)hw->tx + 1; + regs.uregs[fiq_rcount] = hw->len - 1; + regs.uregs[fiq_rirq] = (long)S3C24XX_VA_IRQ; + + set_fiq_regs(®s); + + if (hw->fiq_mode != mode) { + u32 *ack_ptr; + + hw->fiq_mode = mode; + + switch (mode) { + case FIQ_MODE_TX: + code = &s3c24xx_spi_fiq_tx; + break; + case FIQ_MODE_RX: + code = &s3c24xx_spi_fiq_rx; + break; + case FIQ_MODE_TXRX: + code = &s3c24xx_spi_fiq_txrx; + break; + default: + code = NULL; + } + + BUG_ON(!code); + + ack_ptr = (u32 *)&code->data[code->ack_offset]; + *ack_ptr = ack_bit(hw->irq); + + set_fiq_handler(&code->data, code->length); + } + + s3c24xx_set_fiq(hw->irq, true); + + hw->fiq_mode = mode; + hw->fiq_inuse = 1; +} + +/** + * s3c24xx_spi_fiqop - FIQ core code callback + * @pw: Data registered with the handler + * @release: Whether this is a release or a return. + * + * Called by the FIQ code when another module wants to use the FIQ, so + * return whether we are currently using this or not and then update our + * internal state. + */ +static int s3c24xx_spi_fiqop(void *pw, int release) +{ + struct s3c24xx_spi *hw = pw; + int ret = 0; + + if (release) { + if (hw->fiq_inuse) + ret = -EBUSY; + + /* note, we do not need to unroute the FIQ, as the FIQ + * vector code de-routes it to signal the end of transfer */ + + hw->fiq_mode = FIQ_MODE_NONE; + hw->fiq_claimed = 0; + } else { + hw->fiq_claimed = 1; + } + + return ret; +} + +/** + * s3c24xx_spi_initfiq - setup the information for the FIQ core + * @hw: The hardware state. + * + * Setup the fiq_handler block to pass to the FIQ core. + */ +static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw) +{ + hw->fiq_handler.dev_id = hw; + hw->fiq_handler.name = dev_name(hw->dev); + hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop; +} + +/** + * s3c24xx_spi_usefiq - return if we should be using FIQ. + * @hw: The hardware state. + * + * Return true if the platform data specifies whether this channel is + * allowed to use the FIQ. + */ +static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw) +{ + return hw->pdata->use_fiq; +} + +/** + * s3c24xx_spi_usingfiq - return if channel is using FIQ + * @spi: The hardware state. + * + * Return whether the channel is currently using the FIQ (separate from + * whether the FIQ is claimed). + */ +static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi) +{ + return spi->fiq_inuse; +} +#else + +static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { } +static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { } +static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; } +static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; } + +#endif /* CONFIG_SPI_S3C24XX_FIQ */ + static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t) { struct s3c24xx_spi *hw = to_hw(spi); - dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n", - t->tx_buf, t->rx_buf, t->len); - hw->tx = t->tx_buf; hw->rx = t->rx_buf; hw->len = t->len; @@ -228,11 +429,14 @@ static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t) init_completion(&hw->done); + hw->fiq_inuse = 0; + if (s3c24xx_spi_usefiq(hw) && t->len >= 3) + s3c24xx_spi_tryfiq(hw); + /* send the first byte */ writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT); wait_for_completion(&hw->done); - return hw->count; } @@ -254,17 +458,27 @@ static irqreturn_t s3c24xx_spi_irq(int irq, void *dev) goto irq_done; } - hw->count++; + if (!s3c24xx_spi_usingfiq(hw)) { + hw->count++; - if (hw->rx) - hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT); + if (hw->rx) + hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT); - count++; + count++; + + if (count < hw->len) + writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT); + else + complete(&hw->done); + } else { + hw->count = hw->len; + hw->fiq_inuse = 0; + + if (hw->rx) + hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT); - if (count < hw->len) - writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT); - else complete(&hw->done); + } irq_done: return IRQ_HANDLED; @@ -322,6 +536,10 @@ static int __init s3c24xx_spi_probe(struct platform_device *pdev) platform_set_drvdata(pdev, hw); init_completion(&hw->done); + /* initialise fiq handler */ + + s3c24xx_spi_initfiq(hw); + /* setup the master state. */ /* the spi->mode bits understood by this driver: */ diff --git a/drivers/spi/spi_s3c24xx_fiq.S b/drivers/spi/spi_s3c24xx_fiq.S new file mode 100644 index 000000000000..3793cae361db --- /dev/null +++ b/drivers/spi/spi_s3c24xx_fiq.S @@ -0,0 +1,116 @@ +/* linux/drivers/spi/spi_s3c24xx_fiq.S + * + * Copyright 2009 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * + * S3C24XX SPI - FIQ pseudo-DMA transfer code + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#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 diff --git a/drivers/spi/spi_s3c24xx_fiq.h b/drivers/spi/spi_s3c24xx_fiq.h new file mode 100644 index 000000000000..a5950bb25b51 --- /dev/null +++ b/drivers/spi/spi_s3c24xx_fiq.h @@ -0,0 +1,26 @@ +/* linux/drivers/spi/spi_s3c24xx_fiq.h + * + * Copyright 2009 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * + * S3C24XX SPI - FIQ pseudo-DMA transfer support + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +/* We have R8 through R13 to play with */ + +#ifdef __ASSEMBLY__ +#define __REG_NR(x) r##x +#else +#define __REG_NR(x) (x) +#endif + +#define fiq_rspi __REG_NR(8) +#define fiq_rtmp __REG_NR(9) +#define fiq_rrx __REG_NR(10) +#define fiq_rtx __REG_NR(11) +#define fiq_rcount __REG_NR(12) +#define fiq_rirq __REG_NR(13) |