/* 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
#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.
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;
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);
struct s3c2410_spi_info *pdata;
};
+
#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
}
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;
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;
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;
}
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;
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: */
--- /dev/null
+/* 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
projects / linux-beck.git / commitdiff