spi: reorganize drivers

Sort the SPI makefile and enforce the naming convention spi_*.c for
spi drivers.

This change also rolls the contents of atmel_spi.h into the .c file
since there is only one user of that particular include file.

v2: - Use 'spi-' prefix instead of 'spi_' to match what seems to be
      be the predominant pattern for subsystem prefixes.
    - Clean up filenames in Kconfig and header comment blocks

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 1093 insertions, 0 deletions

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
new file mode 100644
index 00000000000..82dee9a6c0d
--- /dev/null
+++ b/drivers/spi/spi-atmel.c
@@ -0,0 +1,1093 @@
+/*
+ * Driver for Atmel AT32 and AT91 SPI Controllers
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+
+#include <asm/io.h>
+#include <mach/board.h>
+#include <mach/gpio.h>
+#include <mach/cpu.h>
+
+/* SPI register offsets */
+#define SPI_CR					0x0000
+#define SPI_MR					0x0004
+#define SPI_RDR					0x0008
+#define SPI_TDR					0x000c
+#define SPI_SR					0x0010
+#define SPI_IER					0x0014
+#define SPI_IDR					0x0018
+#define SPI_IMR					0x001c
+#define SPI_CSR0				0x0030
+#define SPI_CSR1				0x0034
+#define SPI_CSR2				0x0038
+#define SPI_CSR3				0x003c
+#define SPI_RPR					0x0100
+#define SPI_RCR					0x0104
+#define SPI_TPR					0x0108
+#define SPI_TCR					0x010c
+#define SPI_RNPR				0x0110
+#define SPI_RNCR				0x0114
+#define SPI_TNPR				0x0118
+#define SPI_TNCR				0x011c
+#define SPI_PTCR				0x0120
+#define SPI_PTSR				0x0124
+
+/* Bitfields in CR */
+#define SPI_SPIEN_OFFSET			0
+#define SPI_SPIEN_SIZE				1
+#define SPI_SPIDIS_OFFSET			1
+#define SPI_SPIDIS_SIZE				1
+#define SPI_SWRST_OFFSET			7
+#define SPI_SWRST_SIZE				1
+#define SPI_LASTXFER_OFFSET			24
+#define SPI_LASTXFER_SIZE			1
+
+/* Bitfields in MR */
+#define SPI_MSTR_OFFSET				0
+#define SPI_MSTR_SIZE				1
+#define SPI_PS_OFFSET				1
+#define SPI_PS_SIZE				1
+#define SPI_PCSDEC_OFFSET			2
+#define SPI_PCSDEC_SIZE				1
+#define SPI_FDIV_OFFSET				3
+#define SPI_FDIV_SIZE				1
+#define SPI_MODFDIS_OFFSET			4
+#define SPI_MODFDIS_SIZE			1
+#define SPI_LLB_OFFSET				7
+#define SPI_LLB_SIZE				1
+#define SPI_PCS_OFFSET				16
+#define SPI_PCS_SIZE				4
+#define SPI_DLYBCS_OFFSET			24
+#define SPI_DLYBCS_SIZE				8
+
+/* Bitfields in RDR */
+#define SPI_RD_OFFSET				0
+#define SPI_RD_SIZE				16
+
+/* Bitfields in TDR */
+#define SPI_TD_OFFSET				0
+#define SPI_TD_SIZE				16
+
+/* Bitfields in SR */
+#define SPI_RDRF_OFFSET				0
+#define SPI_RDRF_SIZE				1
+#define SPI_TDRE_OFFSET				1
+#define SPI_TDRE_SIZE				1
+#define SPI_MODF_OFFSET				2
+#define SPI_MODF_SIZE				1
+#define SPI_OVRES_OFFSET			3
+#define SPI_OVRES_SIZE				1
+#define SPI_ENDRX_OFFSET			4
+#define SPI_ENDRX_SIZE				1
+#define SPI_ENDTX_OFFSET			5
+#define SPI_ENDTX_SIZE				1
+#define SPI_RXBUFF_OFFSET			6
+#define SPI_RXBUFF_SIZE				1
+#define SPI_TXBUFE_OFFSET			7
+#define SPI_TXBUFE_SIZE				1
+#define SPI_NSSR_OFFSET				8
+#define SPI_NSSR_SIZE				1
+#define SPI_TXEMPTY_OFFSET			9
+#define SPI_TXEMPTY_SIZE			1
+#define SPI_SPIENS_OFFSET			16
+#define SPI_SPIENS_SIZE				1
+
+/* Bitfields in CSR0 */
+#define SPI_CPOL_OFFSET				0
+#define SPI_CPOL_SIZE				1
+#define SPI_NCPHA_OFFSET			1
+#define SPI_NCPHA_SIZE				1
+#define SPI_CSAAT_OFFSET			3
+#define SPI_CSAAT_SIZE				1
+#define SPI_BITS_OFFSET				4
+#define SPI_BITS_SIZE				4
+#define SPI_SCBR_OFFSET				8
+#define SPI_SCBR_SIZE				8
+#define SPI_DLYBS_OFFSET			16
+#define SPI_DLYBS_SIZE				8
+#define SPI_DLYBCT_OFFSET			24
+#define SPI_DLYBCT_SIZE				8
+
+/* Bitfields in RCR */
+#define SPI_RXCTR_OFFSET			0
+#define SPI_RXCTR_SIZE				16
+
+/* Bitfields in TCR */
+#define SPI_TXCTR_OFFSET			0
+#define SPI_TXCTR_SIZE				16
+
+/* Bitfields in RNCR */
+#define SPI_RXNCR_OFFSET			0
+#define SPI_RXNCR_SIZE				16
+
+/* Bitfields in TNCR */
+#define SPI_TXNCR_OFFSET			0
+#define SPI_TXNCR_SIZE				16
+
+/* Bitfields in PTCR */
+#define SPI_RXTEN_OFFSET			0
+#define SPI_RXTEN_SIZE				1
+#define SPI_RXTDIS_OFFSET			1
+#define SPI_RXTDIS_SIZE				1
+#define SPI_TXTEN_OFFSET			8
+#define SPI_TXTEN_SIZE				1
+#define SPI_TXTDIS_OFFSET			9
+#define SPI_TXTDIS_SIZE				1
+
+/* Constants for BITS */
+#define SPI_BITS_8_BPT				0
+#define SPI_BITS_9_BPT				1
+#define SPI_BITS_10_BPT				2
+#define SPI_BITS_11_BPT				3
+#define SPI_BITS_12_BPT				4
+#define SPI_BITS_13_BPT				5
+#define SPI_BITS_14_BPT				6
+#define SPI_BITS_15_BPT				7
+#define SPI_BITS_16_BPT				8
+
+/* Bit manipulation macros */
+#define SPI_BIT(name) \
+	(1 << SPI_##name##_OFFSET)
+#define SPI_BF(name,value) \
+	(((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
+#define SPI_BFEXT(name,value) \
+	(((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
+#define SPI_BFINS(name,value,old) \
+	( ((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
+	  | SPI_BF(name,value))
+
+/* Register access macros */
+#define spi_readl(port,reg) \
+	__raw_readl((port)->regs + SPI_##reg)
+#define spi_writel(port,reg,value) \
+	__raw_writel((value), (port)->regs + SPI_##reg)
+
+
+/*
+ * The core SPI transfer engine just talks to a register bank to set up
+ * DMA transfers; transfer queue progress is driven by IRQs.  The clock
+ * framework provides the base clock, subdivided for each spi_device.
+ */
+struct atmel_spi {
+	spinlock_t		lock;
+
+	void __iomem		*regs;
+	int			irq;
+	struct clk		*clk;
+	struct platform_device	*pdev;
+	struct spi_device	*stay;
+
+	u8			stopping;
+	struct list_head	queue;
+	struct spi_transfer	*current_transfer;
+	unsigned long		current_remaining_bytes;
+	struct spi_transfer	*next_transfer;
+	unsigned long		next_remaining_bytes;
+
+	void			*buffer;
+	dma_addr_t		buffer_dma;
+};
+
+/* Controller-specific per-slave state */
+struct atmel_spi_device {
+	unsigned int		npcs_pin;
+	u32			csr;
+};
+
+#define BUFFER_SIZE		PAGE_SIZE
+#define INVALID_DMA_ADDRESS	0xffffffff
+
+/*
+ * Version 2 of the SPI controller has
+ *  - CR.LASTXFER
+ *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
+ *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
+ *  - SPI_CSRx.CSAAT
+ *  - SPI_CSRx.SBCR allows faster clocking
+ *
+ * We can determine the controller version by reading the VERSION
+ * register, but I haven't checked that it exists on all chips, and
+ * this is cheaper anyway.
+ */
+static bool atmel_spi_is_v2(void)
+{
+	return !cpu_is_at91rm9200();
+}
+
+/*
+ * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
+ * they assume that spi slave device state will not change on deselect, so
+ * that automagic deselection is OK.  ("NPCSx rises if no data is to be
+ * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
+ * controllers have CSAAT and friends.
+ *
+ * Since the CSAAT functionality is a bit weird on newer controllers as
+ * well, we use GPIO to control nCSx pins on all controllers, updating
+ * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
+ * support active-high chipselects despite the controller's belief that
+ * only active-low devices/systems exists.
+ *
+ * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
+ * right when driven with GPIO.  ("Mode Fault does not allow more than one
+ * Master on Chip Select 0.")  No workaround exists for that ... so for
+ * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
+ * and (c) will trigger that first erratum in some cases.
+ *
+ * TODO: Test if the atmel_spi_is_v2() branch below works on
+ * AT91RM9200 if we use some other register than CSR0. However, don't
+ * do this unconditionally since AP7000 has an errata where the BITS
+ * field in CSR0 overrides all other CSRs.
+ */
+
+static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct atmel_spi_device *asd = spi->controller_state;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr;
+
+	if (atmel_spi_is_v2()) {
+		/*
+		 * Always use CSR0. This ensures that the clock
+		 * switches to the correct idle polarity before we
+		 * toggle the CS.
+		 */
+		spi_writel(as, CSR0, asd->csr);
+		spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
+				| SPI_BIT(MSTR));
+		mr = spi_readl(as, MR);
+		gpio_set_value(asd->npcs_pin, active);
+	} else {
+		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
+		int i;
+		u32 csr;
+
+		/* Make sure clock polarity is correct */
+		for (i = 0; i < spi->master->num_chipselect; i++) {
+			csr = spi_readl(as, CSR0 + 4 * i);
+			if ((csr ^ cpol) & SPI_BIT(CPOL))
+				spi_writel(as, CSR0 + 4 * i,
+						csr ^ SPI_BIT(CPOL));
+		}
+
+		mr = spi_readl(as, MR);
+		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+		if (spi->chip_select != 0)
+			gpio_set_value(asd->npcs_pin, active);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
+			asd->npcs_pin, active ? " (high)" : "",
+			mr);
+}
+
+static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct atmel_spi_device *asd = spi->controller_state;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr;
+
+	/* only deactivate *this* device; sometimes transfers to
+	 * another device may be active when this routine is called.
+	 */
+	mr = spi_readl(as, MR);
+	if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
+		mr = SPI_BFINS(PCS, 0xf, mr);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
+			asd->npcs_pin, active ? " (low)" : "",
+			mr);
+
+	if (atmel_spi_is_v2() || spi->chip_select != 0)
+		gpio_set_value(asd->npcs_pin, !active);
+}
+
+static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
+					struct spi_transfer *xfer)
+{
+	return msg->transfers.prev == &xfer->transfer_list;
+}
+
+static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
+{
+	return xfer->delay_usecs == 0 && !xfer->cs_change;
+}
+
+static void atmel_spi_next_xfer_data(struct spi_master *master,
+				struct spi_transfer *xfer,
+				dma_addr_t *tx_dma,
+				dma_addr_t *rx_dma,
+				u32 *plen)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	u32			len = *plen;
+
+	/* use scratch buffer only when rx or tx data is unspecified */
+	if (xfer->rx_buf)
+		*rx_dma = xfer->rx_dma + xfer->len - *plen;
+	else {
+		*rx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+	}
+	if (xfer->tx_buf)
+		*tx_dma = xfer->tx_dma + xfer->len - *plen;
+	else {
+		*tx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+		memset(as->buffer, 0, len);
+		dma_sync_single_for_device(&as->pdev->dev,
+				as->buffer_dma, len, DMA_TO_DEVICE);
+	}
+
+	*plen = len;
+}
+
+/*
+ * Submit next transfer for DMA.
+ * lock is held, spi irq is blocked
+ */
+static void atmel_spi_next_xfer(struct spi_master *master,
+				struct spi_message *msg)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_transfer	*xfer;
+	u32			len, remaining;
+	u32			ieval;
+	dma_addr_t		tx_dma, rx_dma;
+
+	if (!as->current_transfer)
+		xfer = list_entry(msg->transfers.next,
+				struct spi_transfer, transfer_list);
+	else if (!as->next_transfer)
+		xfer = list_entry(as->current_transfer->transfer_list.next,
+				struct spi_transfer, transfer_list);
+	else
+		xfer = NULL;
+
+	if (xfer) {
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+
+		len = xfer->len;
+		atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
+		remaining = xfer->len - len;
+
+		spi_writel(as, RPR, rx_dma);
+		spi_writel(as, TPR, tx_dma);
+
+		if (msg->spi->bits_per_word > 8)
+			len >>= 1;
+		spi_writel(as, RCR, len);
+		spi_writel(as, TCR, len);
+
+		dev_dbg(&msg->spi->dev,
+			"  start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
+			xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
+			xfer->rx_buf, xfer->rx_dma);
+	} else {
+		xfer = as->next_transfer;
+		remaining = as->next_remaining_bytes;
+	}
+
+	as->current_transfer = xfer;
+	as->current_remaining_bytes = remaining;
+
+	if (remaining > 0)
+		len = remaining;
+	else if (!atmel_spi_xfer_is_last(msg, xfer)
+			&& atmel_spi_xfer_can_be_chained(xfer)) {
+		xfer = list_entry(xfer->transfer_list.next,
+				struct spi_transfer, transfer_list);
+		len = xfer->len;
+	} else
+		xfer = NULL;
+
+	as->next_transfer = xfer;
+
+	if (xfer) {
+		u32	total;
+
+		total = len;
+		atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
+		as->next_remaining_bytes = total - len;
+
+		spi_writel(as, RNPR, rx_dma);
+		spi_writel(as, TNPR, tx_dma);
+
+		if (msg->spi->bits_per_word > 8)
+			len >>= 1;
+		spi_writel(as, RNCR, len);
+		spi_writel(as, TNCR, len);
+
+		dev_dbg(&msg->spi->dev,
+			"  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
+			xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
+			xfer->rx_buf, xfer->rx_dma);
+		ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
+	} else {
+		spi_writel(as, RNCR, 0);
+		spi_writel(as, TNCR, 0);
+		ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
+	}
+
+	/* REVISIT: We're waiting for ENDRX before we start the next
+	 * transfer because we need to handle some difficult timing
+	 * issues otherwise. If we wait for ENDTX in one transfer and
+	 * then starts waiting for ENDRX in the next, it's difficult
+	 * to tell the difference between the ENDRX interrupt we're
+	 * actually waiting for and the ENDRX interrupt of the
+	 * previous transfer.
+	 *
+	 * It should be doable, though. Just not now...
+	 */
+	spi_writel(as, IER, ieval);
+	spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
+}
+
+static void atmel_spi_next_message(struct spi_master *master)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+	struct spi_device	*spi;
+
+	BUG_ON(as->current_transfer);
+
+	msg = list_entry(as->queue.next, struct spi_message, queue);
+	spi = msg->spi;
+
+	dev_dbg(master->dev.parent, "start message %p for %s\n",
+			msg, dev_name(&spi->dev));
+
+	/* select chip if it's not still active */
+	if (as->stay) {
+		if (as->stay != spi) {
+			cs_deactivate(as, as->stay);
+			cs_activate(as, spi);
+		}
+		as->stay = NULL;
+	} else
+		cs_activate(as, spi);
+
+	atmel_spi_next_xfer(master, msg);
+}
+
+/*
+ * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
+ *  - The buffer is either valid for CPU access, else NULL
+ *  - If the buffer is valid, so is its DMA address
+ *
+ * This driver manages the dma address unless message->is_dma_mapped.
+ */
+static int
+atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
+{
+	struct device	*dev = &as->pdev->dev;
+
+	xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
+	if (xfer->tx_buf) {
+		/* tx_buf is a const void* where we need a void * for the dma
+		 * mapping */
+		void *nonconst_tx = (void *)xfer->tx_buf;
+
+		xfer->tx_dma = dma_map_single(dev,
+				nonconst_tx, xfer->len,
+				DMA_TO_DEVICE);
+		if (dma_mapping_error(dev, xfer->tx_dma))
+			return -ENOMEM;
+	}
+	if (xfer->rx_buf) {
+		xfer->rx_dma = dma_map_single(dev,
+				xfer->rx_buf, xfer->len,
+				DMA_FROM_DEVICE);
+		if (dma_mapping_error(dev, xfer->rx_dma)) {
+			if (xfer->tx_buf)
+				dma_unmap_single(dev,
+						xfer->tx_dma, xfer->len,
+						DMA_TO_DEVICE);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
+				     struct spi_transfer *xfer)
+{
+	if (xfer->tx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->dev.parent, xfer->tx_dma,
+				 xfer->len, DMA_TO_DEVICE);
+	if (xfer->rx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->dev.parent, xfer->rx_dma,
+				 xfer->len, DMA_FROM_DEVICE);
+}
+
+static void
+atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
+		struct spi_message *msg, int status, int stay)
+{
+	if (!stay || status < 0)
+		cs_deactivate(as, msg->spi);
+	else
+		as->stay = msg->spi;
+
+	list_del(&msg->queue);
+	msg->status = status;
+
+	dev_dbg(master->dev.parent,
+		"xfer complete: %u bytes transferred\n",
+		msg->actual_length);
+
+	spin_unlock(&as->lock);
+	msg->complete(msg->context);
+	spin_lock(&as->lock);
+
+	as->current_transfer = NULL;
+	as->next_transfer = NULL;
+
+	/* continue if needed */
+	if (list_empty(&as->queue) || as->stopping)
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+	else
+		atmel_spi_next_message(master);
+}
+
+static irqreturn_t
+atmel_spi_interrupt(int irq, void *dev_id)
+{
+	struct spi_master	*master = dev_id;
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+	struct spi_transfer	*xfer;
+	u32			status, pending, imr;
+	int			ret = IRQ_NONE;
+
+	spin_lock(&as->lock);
+
+	xfer = as->current_transfer;
+	msg = list_entry(as->queue.next, struct spi_message, queue);
+
+	imr = spi_readl(as, IMR);
+	status = spi_readl(as, SR);
+	pending = status & imr;
+
+	if (pending & SPI_BIT(OVRES)) {
+		int timeout;
+
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
+				     | SPI_BIT(OVRES)));
+
+		/*
+		 * When we get an overrun, we disregard the current
+		 * transfer. Data will not be copied back from any
+		 * bounce buffer and msg->actual_len will not be
+		 * updated with the last xfer.
+		 *
+		 * We will also not process any remaning transfers in
+		 * the message.
+		 *
+		 * First, stop the transfer and unmap the DMA buffers.
+		 */
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+		if (!msg->is_dma_mapped)
+			atmel_spi_dma_unmap_xfer(master, xfer);
+
+		/* REVISIT: udelay in irq is unfriendly */
+		if (xfer->delay_usecs)
+			udelay(xfer->delay_usecs);
+
+		dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
+			 spi_readl(as, TCR), spi_readl(as, RCR));
+
+		/*
+		 * Clean up DMA registers and make sure the data
+		 * registers are empty.
+		 */
+		spi_writel(as, RNCR, 0);
+		spi_writel(as, TNCR, 0);
+		spi_writel(as, RCR, 0);
+		spi_writel(as, TCR, 0);
+		for (timeout = 1000; timeout; timeout--)
+			if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
+				break;
+		if (!timeout)
+			dev_warn(master->dev.parent,
+				 "timeout waiting for TXEMPTY");
+		while (spi_readl(as, SR) & SPI_BIT(RDRF))
+			spi_readl(as, RDR);
+
+		/* Clear any overrun happening while cleaning up */
+		spi_readl(as, SR);
+
+		atmel_spi_msg_done(master, as, msg, -EIO, 0);
+	} else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, pending);
+
+		if (as->current_remaining_bytes == 0) {
+			msg->actual_length += xfer->len;
+
+			if (!msg->is_dma_mapped)
+				atmel_spi_dma_unmap_xfer(master, xfer);
+
+			/* REVISIT: udelay in irq is unfriendly */
+			if (xfer->delay_usecs)
+				udelay(xfer->delay_usecs);
+
+			if (atmel_spi_xfer_is_last(msg, xfer)) {
+				/* report completed message */
+				atmel_spi_msg_done(master, as, msg, 0,
+						xfer->cs_change);
+			} else {
+				if (xfer->cs_change) {
+					cs_deactivate(as, msg->spi);
+					udelay(1);
+					cs_activate(as, msg->spi);
+				}
+
+				/*
+				 * Not done yet. Submit the next transfer.
+				 *
+				 * FIXME handle protocol options for xfer
+				 */
+				atmel_spi_next_xfer(master, msg);
+			}
+		} else {
+			/*
+			 * Keep going, we still have data to send in
+			 * the current transfer.
+			 */
+			atmel_spi_next_xfer(master, msg);
+		}
+	}
+
+	spin_unlock(&as->lock);
+
+	return ret;
+}
+
+static int atmel_spi_setup(struct spi_device *spi)
+{
+	struct atmel_spi	*as;
+	struct atmel_spi_device	*asd;
+	u32			scbr, csr;
+	unsigned int		bits = spi->bits_per_word;
+	unsigned long		bus_hz;
+	unsigned int		npcs_pin;
+	int			ret;
+
+	as = spi_master_get_devdata(spi->master);
+
+	if (as->stopping)
+		return -ESHUTDOWN;
+
+	if (spi->chip_select > spi->master->num_chipselect) {
+		dev_dbg(&spi->dev,
+				"setup: invalid chipselect %u (%u defined)\n",
+				spi->chip_select, spi->master->num_chipselect);
+		return -EINVAL;
+	}
+
+	if (bits < 8 || bits > 16) {
+		dev_dbg(&spi->dev,
+				"setup: invalid bits_per_word %u (8 to 16)\n",
+				bits);
+		return -EINVAL;
+	}
+
+	/* see notes above re chipselect */
+	if (!atmel_spi_is_v2()
+			&& spi->chip_select == 0
+			&& (spi->mode & SPI_CS_HIGH)) {
+		dev_dbg(&spi->dev, "setup: can't be active-high\n");
+		return -EINVAL;
+	}
+
+	/* v1 chips start out at half the peripheral bus speed. */
+	bus_hz = clk_get_rate(as->clk);
+	if (!atmel_spi_is_v2())
+		bus_hz /= 2;
+
+	if (spi->max_speed_hz) {
+		/*
+		 * Calculate the lowest divider that satisfies the
+		 * constraint, assuming div32/fdiv/mbz == 0.
+		 */
+		scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz);
+
+		/*
+		 * If the resulting divider doesn't fit into the
+		 * register bitfield, we can't satisfy the constraint.
+		 */
+		if (scbr >= (1 << SPI_SCBR_SIZE)) {
+			dev_dbg(&spi->dev,
+				"setup: %d Hz too slow, scbr %u; min %ld Hz\n",
+				spi->max_speed_hz, scbr, bus_hz/255);
+			return -EINVAL;
+		}
+	} else
+		/* speed zero means "as slow as possible" */
+		scbr = 0xff;
+
+	csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
+	if (spi->mode & SPI_CPOL)
+		csr |= SPI_BIT(CPOL);
+	if (!(spi->mode & SPI_CPHA))
+		csr |= SPI_BIT(NCPHA);
+
+	/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
+	 *
+	 * DLYBCT would add delays between words, slowing down transfers.
+	 * It could potentially be useful to cope with DMA bottlenecks, but
+	 * in those cases it's probably best to just use a lower bitrate.
+	 */
+	csr |= SPI_BF(DLYBS, 0);
+	csr |= SPI_BF(DLYBCT, 0);
+
+	/* chipselect must have been muxed as GPIO (e.g. in board setup) */
+	npcs_pin = (unsigned int)spi->controller_data;
+	asd = spi->controller_state;
+	if (!asd) {
+		asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
+		if (!asd)
+			return -ENOMEM;
+
+		ret = gpio_request(npcs_pin, dev_name(&spi->dev));
+		if (ret) {
+			kfree(asd);
+			return ret;
+		}
+
+		asd->npcs_pin = npcs_pin;
+		spi->controller_state = asd;
+		gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
+	} else {
+		unsigned long		flags;
+
+		spin_lock_irqsave(&as->lock, flags);
+		if (as->stay == spi)
+			as->stay = NULL;
+		cs_deactivate(as, spi);
+		spin_unlock_irqrestore(&as->lock, flags);
+	}
+
+	asd->csr = csr;
+
+	dev_dbg(&spi->dev,
+		"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
+		bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
+
+	if (!atmel_spi_is_v2())
+		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+
+	return 0;
+}
+
+static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
+{
+	struct atmel_spi	*as;
+	struct spi_transfer	*xfer;
+	unsigned long		flags;
+	struct device		*controller = spi->master->dev.parent;
+	u8			bits;
+	struct atmel_spi_device	*asd;
+
+	as = spi_master_get_devdata(spi->master);
+
+	dev_dbg(controller, "new message %p submitted for %s\n",
+			msg, dev_name(&spi->dev));
+
+	if (unlikely(list_empty(&msg->transfers)))
+		return -EINVAL;
+
+	if (as->stopping)
+		return -ESHUTDOWN;
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
+			dev_dbg(&spi->dev, "missing rx or tx buf\n");
+			return -EINVAL;
+		}
+
+		if (xfer->bits_per_word) {
+			asd = spi->controller_state;
+			bits = (asd->csr >> 4) & 0xf;
+			if (bits != xfer->bits_per_word - 8) {
+				dev_dbg(&spi->dev, "you can't yet change "
+					 "bits_per_word in transfers\n");
+				return -ENOPROTOOPT;
+			}
+		}
+
+		/* FIXME implement these protocol options!! */
+		if (xfer->speed_hz) {
+			dev_dbg(&spi->dev, "no protocol options yet\n");
+			return -ENOPROTOOPT;
+		}
+
+		/*
+		 * DMA map early, for performance (empties dcache ASAP) and
+		 * better fault reporting.  This is a DMA-only driver.
+		 *
+		 * NOTE that if dma_unmap_single() ever starts to do work on
+		 * platforms supported by this driver, we would need to clean
+		 * up mappings for previously-mapped transfers.
+		 */
+		if (!msg->is_dma_mapped) {
+			if (atmel_spi_dma_map_xfer(as, xfer) < 0)
+				return -ENOMEM;
+		}
+	}
+
+#ifdef VERBOSE
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		dev_dbg(controller,
+			"  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
+			xfer, xfer->len,
+			xfer->tx_buf, xfer->tx_dma,
+			xfer->rx_buf, xfer->rx_dma);
+	}
+#endif
+
+	msg->status = -EINPROGRESS;
+	msg->actual_length = 0;
+
+	spin_lock_irqsave(&as->lock, flags);
+	list_add_tail(&msg->queue, &as->queue);
+	if (!as->current_transfer)
+		atmel_spi_next_message(spi->master);
+	spin_unlock_irqrestore(&as->lock, flags);
+
+	return 0;
+}
+
+static void atmel_spi_cleanup(struct spi_device *spi)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(spi->master);
+	struct atmel_spi_device	*asd = spi->controller_state;
+	unsigned		gpio = (unsigned) spi->controller_data;
+	unsigned long		flags;
+
+	if (!asd)
+		return;
+
+	spin_lock_irqsave(&as->lock, flags);
+	if (as->stay == spi) {
+		as->stay = NULL;
+		cs_deactivate(as, spi);
+	}
+	spin_unlock_irqrestore(&as->lock, flags);
+
+	spi->controller_state = NULL;
+	gpio_free(gpio);
+	kfree(asd);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int __init atmel_spi_probe(struct platform_device *pdev)
+{
+	struct resource		*regs;
+	int			irq;
+	struct clk		*clk;
+	int			ret;
+	struct spi_master	*master;
+	struct atmel_spi	*as;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs)
+		return -ENXIO;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	clk = clk_get(&pdev->dev, "spi_clk");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	/* setup spi core then atmel-specific driver state */
+	ret = -ENOMEM;
+	master = spi_alloc_master(&pdev->dev, sizeof *as);
+	if (!master)
+		goto out_free;
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+
+	master->bus_num = pdev->id;
+	master->num_chipselect = 4;
+	master->setup = atmel_spi_setup;
+	master->transfer = atmel_spi_transfer;
+	master->cleanup = atmel_spi_cleanup;
+	platform_set_drvdata(pdev, master);
+
+	as = spi_master_get_devdata(master);
+
+	/*
+	 * Scratch buffer is used for throwaway rx and tx data.
+	 * It's coherent to minimize dcache pollution.
+	 */
+	as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
+					&as->buffer_dma, GFP_KERNEL);
+	if (!as->buffer)
+		goto out_free;
+
+	spin_lock_init(&as->lock);
+	INIT_LIST_HEAD(&as->queue);
+	as->pdev = pdev;
+	as->regs = ioremap(regs->start, resource_size(regs));
+	if (!as->regs)
+		goto out_free_buffer;
+	as->irq = irq;
+	as->clk = clk;
+
+	ret = request_irq(irq, atmel_spi_interrupt, 0,
+			dev_name(&pdev->dev), master);
+	if (ret)
+		goto out_unmap_regs;
+
+	/* Initialize the hardware */
+	clk_enable(clk);
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
+	spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+	spi_writel(as, CR, SPI_BIT(SPIEN));
+
+	/* go! */
+	dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
+			(unsigned long)regs->start, irq);
+
+	ret = spi_register_master(master);
+	if (ret)
+		goto out_reset_hw;
+
+	return 0;
+
+out_reset_hw:
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	clk_disable(clk);
+	free_irq(irq, master);
+out_unmap_regs:
+	iounmap(as->regs);
+out_free_buffer:
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+out_free:
+	clk_put(clk);
+	spi_master_put(master);
+	return ret;
+}
+
+static int __exit atmel_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+
+	/* reset the hardware and block queue progress */
+	spin_lock_irq(&as->lock);
+	as->stopping = 1;
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	spi_readl(as, SR);
+	spin_unlock_irq(&as->lock);
+
+	/* Terminate remaining queued transfers */
+	list_for_each_entry(msg, &as->queue, queue) {
+		/* REVISIT unmapping the dma is a NOP on ARM and AVR32
+		 * but we shouldn't depend on that...
+		 */
+		msg->status = -ESHUTDOWN;
+		msg->complete(msg->context);
+	}
+
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+
+	clk_disable(as->clk);
+	clk_put(as->clk);
+	free_irq(as->irq, master);
+	iounmap(as->regs);
+
+	spi_unregister_master(master);
+
+	return 0;
+}
+
+#ifdef	CONFIG_PM
+
+static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	clk_disable(as->clk);
+	return 0;
+}
+
+static int atmel_spi_resume(struct platform_device *pdev)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	clk_enable(as->clk);
+	return 0;
+}
+
+#else
+#define	atmel_spi_suspend	NULL
+#define	atmel_spi_resume	NULL
+#endif
+
+
+static struct platform_driver atmel_spi_driver = {
+	.driver		= {
+		.name	= "atmel_spi",
+		.owner	= THIS_MODULE,
+	},
+	.suspend	= atmel_spi_suspend,
+	.resume		= atmel_spi_resume,
+	.remove		= __exit_p(atmel_spi_remove),
+};
+
+static int __init atmel_spi_init(void)
+{
+	return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
+}
+module_init(atmel_spi_init);
+
+static void __exit atmel_spi_exit(void)
+{
+	platform_driver_unregister(&atmel_spi_driver);
+}
+module_exit(atmel_spi_exit);
+
+MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
+MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:atmel_spi");