arch/powerpc/platforms/pasemi/dma_lib.c - kernel/msm - Gitiles

 /*
  * Copyright (C) 2006-2007 PA Semi, Inc
  *
  * Common functions for DMA access on PA Semi PWRficient
  *
  * 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.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/of.h>

 #include <asm/pasemi_dma.h>

 #define MAX_TXCH 64
 #define MAX_RXCH 64

 static struct pasdma_status *dma_status;

 static void __iomem *iob_regs;
 static void __iomem *mac_regs[6];
 static void __iomem *dma_regs;

 static int base_hw_irq;

 static int num_txch, num_rxch;

 static struct pci_dev *dma_pdev;

 /* Bitmaps to handle allocation of channels */

 static DECLARE_BITMAP(txch_free, MAX_TXCH);
 static DECLARE_BITMAP(rxch_free, MAX_RXCH);

 /* pasemi_read_iob_reg - read IOB register
  * @reg: Register to read (offset into PCI CFG space)
  */
 unsigned int pasemi_read_iob_reg(unsigned int reg)
 {
 	return in_le32(iob_regs+reg);
 }
 EXPORT_SYMBOL(pasemi_read_iob_reg);

 /* pasemi_write_iob_reg - write IOB register
  * @reg: Register to write to (offset into PCI CFG space)
  * @val: Value to write
  */
 void pasemi_write_iob_reg(unsigned int reg, unsigned int val)
 {
 	out_le32(iob_regs+reg, val);
 }
 EXPORT_SYMBOL(pasemi_write_iob_reg);

 /* pasemi_read_mac_reg - read MAC register
  * @intf: MAC interface
  * @reg: Register to read (offset into PCI CFG space)
  */
 unsigned int pasemi_read_mac_reg(int intf, unsigned int reg)
 {
 	return in_le32(mac_regs[intf]+reg);
 }
 EXPORT_SYMBOL(pasemi_read_mac_reg);

 /* pasemi_write_mac_reg - write MAC register
  * @intf: MAC interface
  * @reg: Register to write to (offset into PCI CFG space)
  * @val: Value to write
  */
 void pasemi_write_mac_reg(int intf, unsigned int reg, unsigned int val)
 {
 	out_le32(mac_regs[intf]+reg, val);
 }
 EXPORT_SYMBOL(pasemi_write_mac_reg);

 /* pasemi_read_dma_reg - read DMA register
  * @reg: Register to read (offset into PCI CFG space)
  */
 unsigned int pasemi_read_dma_reg(unsigned int reg)
 {
 	return in_le32(dma_regs+reg);
 }
 EXPORT_SYMBOL(pasemi_read_dma_reg);

 /* pasemi_write_dma_reg - write DMA register
  * @reg: Register to write to (offset into PCI CFG space)
  * @val: Value to write
  */
 void pasemi_write_dma_reg(unsigned int reg, unsigned int val)
 {
 	out_le32(dma_regs+reg, val);
 }
 EXPORT_SYMBOL(pasemi_write_dma_reg);

 static int pasemi_alloc_tx_chan(enum pasemi_dmachan_type type)
 {
 	int bit;
 	int start, limit;

 	switch (type & (TXCHAN_EVT0|TXCHAN_EVT1)) {
 	case TXCHAN_EVT0:
 		start = 0;
 		limit = 10;
 		break;
 	case TXCHAN_EVT1:
 		start = 10;
 		limit = MAX_TXCH;
 		break;
 	default:
 		start = 0;
 		limit = MAX_TXCH;
 		break;
 	}
 retry:
 	bit = find_next_bit(txch_free, MAX_TXCH, start);
 	if (bit >= limit)
 		return -ENOSPC;
 	if (!test_and_clear_bit(bit, txch_free))
 		goto retry;

 	return bit;
 }

 static void pasemi_free_tx_chan(int chan)
 {
 	BUG_ON(test_bit(chan, txch_free));
 	set_bit(chan, txch_free);
 }

 static int pasemi_alloc_rx_chan(void)
 {
 	int bit;
 retry:
 	bit = find_first_bit(rxch_free, MAX_RXCH);
 	if (bit >= MAX_TXCH)
 		return -ENOSPC;
 	if (!test_and_clear_bit(bit, rxch_free))
 		goto retry;

 	return bit;
 }

 static void pasemi_free_rx_chan(int chan)
 {
 	BUG_ON(test_bit(chan, rxch_free));
 	set_bit(chan, rxch_free);
 }

 /* pasemi_dma_alloc_chan - Allocate a DMA channel
  * @type: Type of channel to allocate
  * @total_size: Total size of structure to allocate (to allow for more
  *		room behind the structure to be used by the client)
  * @offset: Offset in bytes from start of the total structure to the beginning
  *	    of struct pasemi_dmachan. Needed when struct pasemi_dmachan is
  *	    not the first member of the client structure.
  *
  * pasemi_dma_alloc_chan allocates a DMA channel for use by a client. The
  * type argument specifies whether it's a RX or TX channel, and in the case
  * of TX channels which group it needs to belong to (if any).
  *
  * Returns a pointer to the total structure allocated on success, NULL
  * on failure.
  */
 void *pasemi_dma_alloc_chan(enum pasemi_dmachan_type type,
 			    int total_size, int offset)
 {
 	void *buf;
 	struct pasemi_dmachan *chan;
 	int chno;

 	BUG_ON(total_size < sizeof(struct pasemi_dmachan));

 	buf = kzalloc(total_size, GFP_KERNEL);

 	if (!buf)
 		return NULL;
 	chan = buf + offset;

 	chan->priv = buf;

 	switch (type & (TXCHAN|RXCHAN)) {
 	case RXCHAN:
 		chno = pasemi_alloc_rx_chan();
 		chan->chno = chno;
 		chan->irq = irq_create_mapping(NULL,
 					       base_hw_irq + num_txch + chno);
 		chan->status = &dma_status->rx_sta[chno];
 		break;
 	case TXCHAN:
 		chno = pasemi_alloc_tx_chan(type);
 		chan->chno = chno;
 		chan->irq = irq_create_mapping(NULL, base_hw_irq + chno);
 		chan->status = &dma_status->tx_sta[chno];
 		break;
 	}

 	chan->chan_type = type;

 	return chan;
 }
 EXPORT_SYMBOL(pasemi_dma_alloc_chan);

 /* pasemi_dma_free_chan - Free a previously allocated channel
  * @chan: Channel to free
  *
  * Frees a previously allocated channel. It will also deallocate any
  * descriptor ring associated with the channel, if allocated.
  */
 void pasemi_dma_free_chan(struct pasemi_dmachan *chan)
 {
 	if (chan->ring_virt)
 		pasemi_dma_free_ring(chan);

 	switch (chan->chan_type & (RXCHAN|TXCHAN)) {
 	case RXCHAN:
 		pasemi_free_rx_chan(chan->chno);
 		break;
 	case TXCHAN:
 		pasemi_free_tx_chan(chan->chno);
 		break;
 	}

 	kfree(chan->priv);
 }
 EXPORT_SYMBOL(pasemi_dma_free_chan);

 /* pasemi_dma_alloc_ring - Allocate descriptor ring for a channel
  * @chan: Channel for which to allocate
  * @ring_size: Ring size in 64-bit (8-byte) words
  *
  * Allocate a descriptor ring for a channel. Returns 0 on success, errno
  * on failure. The passed in struct pasemi_dmachan is updated with the
  * virtual and DMA addresses of the ring.
  */
 int pasemi_dma_alloc_ring(struct pasemi_dmachan *chan, int ring_size)
 {
 	BUG_ON(chan->ring_virt);

 	chan->ring_size = ring_size;

 	chan->ring_virt = dma_alloc_coherent(&dma_pdev->dev,
 					     ring_size * sizeof(u64),
 					     &chan->ring_dma, GFP_KERNEL);

 	if (!chan->ring_virt)
 		return -ENOMEM;

 	memset(chan->ring_virt, 0, ring_size * sizeof(u64));

 	return 0;
 }
 EXPORT_SYMBOL(pasemi_dma_alloc_ring);

 /* pasemi_dma_free_ring - Free an allocated descriptor ring for a channel
  * @chan: Channel for which to free the descriptor ring
  *
  * Frees a previously allocated descriptor ring for a channel.
  */
 void pasemi_dma_free_ring(struct pasemi_dmachan *chan)
 {
 	BUG_ON(!chan->ring_virt);

 	dma_free_coherent(&dma_pdev->dev, chan->ring_size * sizeof(u64),
 			  chan->ring_virt, chan->ring_dma);
 	chan->ring_virt = NULL;
 	chan->ring_size = 0;
 	chan->ring_dma = 0;
 }
 EXPORT_SYMBOL(pasemi_dma_free_ring);

 /* pasemi_dma_start_chan - Start a DMA channel
  * @chan: Channel to start
  * @cmdsta: Additional CCMDSTA/TCMDSTA bits to write
  *
  * Enables (starts) a DMA channel with optional additional arguments.
  */
 void pasemi_dma_start_chan(const struct pasemi_dmachan *chan, const u32 cmdsta)
 {
 	if (chan->chan_type == RXCHAN)
 		pasemi_write_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(chan->chno),
 				     cmdsta | PAS_DMA_RXCHAN_CCMDSTA_EN);
 	else
 		pasemi_write_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(chan->chno),
 				     cmdsta | PAS_DMA_TXCHAN_TCMDSTA_EN);
 }
 EXPORT_SYMBOL(pasemi_dma_start_chan);

 /* pasemi_dma_stop_chan - Stop a DMA channel
  * @chan: Channel to stop
  *
  * Stops (disables) a DMA channel. This is done by setting the ST bit in the
  * CMDSTA register and waiting on the ACT (active) bit to clear, then
  * finally disabling the whole channel.
  *
  * This function will only try for a short while for the channel to stop, if
  * it doesn't it will return failure.
  *
  * Returns 1 on success, 0 on failure.
  */
 #define MAX_RETRIES 5000
 int pasemi_dma_stop_chan(const struct pasemi_dmachan *chan)
 {
 	int reg, retries;
 	u32 sta;

 	if (chan->chan_type == RXCHAN) {
 		reg = PAS_DMA_RXCHAN_CCMDSTA(chan->chno);
 		pasemi_write_dma_reg(reg, PAS_DMA_RXCHAN_CCMDSTA_ST);
 		for (retries = 0; retries < MAX_RETRIES; retries++) {
 			sta = pasemi_read_dma_reg(reg);
 			if (!(sta & PAS_DMA_RXCHAN_CCMDSTA_ACT)) {
 				pasemi_write_dma_reg(reg, 0);
 				return 1;
 			}
 			cond_resched();
 		}
 	} else {
 		reg = PAS_DMA_TXCHAN_TCMDSTA(chan->chno);
 		pasemi_write_dma_reg(reg, PAS_DMA_TXCHAN_TCMDSTA_ST);
 		for (retries = 0; retries < MAX_RETRIES; retries++) {
 			sta = pasemi_read_dma_reg(reg);
 			if (!(sta & PAS_DMA_TXCHAN_TCMDSTA_ACT)) {
 				pasemi_write_dma_reg(reg, 0);
 				return 1;
 			}
 			cond_resched();
 		}
 	}

 	return 0;
 }
 EXPORT_SYMBOL(pasemi_dma_stop_chan);

 /* pasemi_dma_alloc_buf - Allocate a buffer to use for DMA
  * @chan: Channel to allocate for
  * @size: Size of buffer in bytes
  * @handle: DMA handle
  *
  * Allocate a buffer to be used by the DMA engine for read/write,
  * similar to dma_alloc_coherent().
  *
  * Returns the virtual address of the buffer, or NULL in case of failure.
  */
 void *pasemi_dma_alloc_buf(struct pasemi_dmachan *chan, int size,
 			   dma_addr_t *handle)
 {
 	return dma_alloc_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
 }
 EXPORT_SYMBOL(pasemi_dma_alloc_buf);

 /* pasemi_dma_free_buf - Free a buffer used for DMA
  * @chan: Channel the buffer was allocated for
  * @size: Size of buffer in bytes
  * @handle: DMA handle
  *
  * Frees a previously allocated buffer.
  */
 void pasemi_dma_free_buf(struct pasemi_dmachan *chan, int size,
 			 dma_addr_t *handle)
 {
 	dma_free_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
 }
 EXPORT_SYMBOL(pasemi_dma_free_buf);

 static void *map_onedev(struct pci_dev *p, int index)
 {
 	struct device_node *dn;
 	void __iomem *ret;

 	dn = pci_device_to_OF_node(p);
 	if (!dn)
 		goto fallback;

 	ret = of_iomap(dn, index);
 	if (!ret)
 		goto fallback;

 	return ret;
 fallback:
 	/* This is hardcoded and ugly, but we have some firmware versions
 	 * that don't provide the register space in the device tree. Luckily
 	 * they are at well-known locations so we can just do the math here.
 	 */
 	return ioremap(0xe0000000 + (p->devfn << 12), 0x2000);
 }

 /* pasemi_dma_init - Initialize the PA Semi DMA library
  *
  * This function initializes the DMA library. It must be called before
  * any other function in the library.
  *
  * Returns 0 on success, errno on failure.
  */
 int pasemi_dma_init(void)
 {
 	static spinlock_t init_lock = SPIN_LOCK_UNLOCKED;
 	struct pci_dev *iob_pdev;
 	struct pci_dev *pdev;
 	struct resource res;
 	struct device_node *dn;
 	int i, intf, err = 0;
 	unsigned long timeout;
 	u32 tmp;

 	if (!machine_is(pasemi))
 		return -ENODEV;

 	spin_lock(&init_lock);

 	/* Make sure we haven't already initialized */
 	if (dma_pdev)
 		goto out;

 	iob_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa001, NULL);
 	if (!iob_pdev) {
 		BUG();
 		printk(KERN_WARNING "Can't find I/O Bridge\n");
 		err = -ENODEV;
 		goto out;
 	}
 	iob_regs = map_onedev(iob_pdev, 0);

 	dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
 	if (!dma_pdev) {
 		BUG();
 		printk(KERN_WARNING "Can't find DMA controller\n");
 		err = -ENODEV;
 		goto out;
 	}
 	dma_regs = map_onedev(dma_pdev, 0);
 	base_hw_irq = virq_to_hw(dma_pdev->irq);

 	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_TXCH, &tmp);
 	num_txch = (tmp & PAS_DMA_CAP_TXCH_TCHN_M) >> PAS_DMA_CAP_TXCH_TCHN_S;

 	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_RXCH, &tmp);
 	num_rxch = (tmp & PAS_DMA_CAP_RXCH_RCHN_M) >> PAS_DMA_CAP_RXCH_RCHN_S;

 	intf = 0;
 	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, NULL);
 	     pdev;
 	     pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, pdev))
 		mac_regs[intf++] = map_onedev(pdev, 0);

 	pci_dev_put(pdev);

 	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, NULL);
 	     pdev;
 	     pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, pdev))
 		mac_regs[intf++] = map_onedev(pdev, 0);

 	pci_dev_put(pdev);

 	dn = pci_device_to_OF_node(iob_pdev);
 	if (dn)
 		err = of_address_to_resource(dn, 1, &res);
 	if (!dn || err) {
 		/* Fallback for old firmware */
 		res.start = 0xfd800000;
 		res.end = res.start + 0x1000;
 	}
 	dma_status = __ioremap(res.start, res.end-res.start, 0);
 	pci_dev_put(iob_pdev);

 	for (i = 0; i < MAX_TXCH; i++)
 		__set_bit(i, txch_free);

 	for (i = 0; i < MAX_RXCH; i++)
 		__set_bit(i, rxch_free);

 	timeout = jiffies + HZ;
 	pasemi_write_dma_reg(PAS_DMA_COM_RXCMD, 0);
 	while (pasemi_read_dma_reg(PAS_DMA_COM_RXSTA) & 1) {
 		if (time_after(jiffies, timeout)) {
 			pr_warning("Warning: Could not disable RX section\n");
 			break;
 		}
 	}

 	timeout = jiffies + HZ;
 	pasemi_write_dma_reg(PAS_DMA_COM_TXCMD, 0);
 	while (pasemi_read_dma_reg(PAS_DMA_COM_TXSTA) & 1) {
 		if (time_after(jiffies, timeout)) {
 			pr_warning("Warning: Could not disable TX section\n");
 			break;
 		}
 	}

 	/* setup resource allocations for the different DMA sections */
 	tmp = pasemi_read_dma_reg(PAS_DMA_COM_CFG);
 	pasemi_write_dma_reg(PAS_DMA_COM_CFG, tmp | 0x18000000);

 	/* enable tx section */
 	pasemi_write_dma_reg(PAS_DMA_COM_TXCMD, PAS_DMA_COM_TXCMD_EN);

 	/* enable rx section */
 	pasemi_write_dma_reg(PAS_DMA_COM_RXCMD, PAS_DMA_COM_RXCMD_EN);

 	printk(KERN_INFO "PA Semi PWRficient DMA library initialized "
 		"(%d tx, %d rx channels)\n", num_txch, num_rxch);

 out:
 	spin_unlock(&init_lock);
 	return err;
 }
 EXPORT_SYMBOL(pasemi_dma_init);
	/*
	* Copyright (C) 2006-2007 PA Semi, Inc
	*
	* Common functions for DMA access on PA Semi PWRficient
	*
	* 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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/of.h>

	#include <asm/pasemi_dma.h>

	#define MAX_TXCH 64
	#define MAX_RXCH 64

	static struct pasdma_status *dma_status;

	static void __iomem *iob_regs;
	static void __iomem *mac_regs[6];
	static void __iomem *dma_regs;

	static int base_hw_irq;

	static int num_txch, num_rxch;

	static struct pci_dev *dma_pdev;

	/* Bitmaps to handle allocation of channels */

	static DECLARE_BITMAP(txch_free, MAX_TXCH);
	static DECLARE_BITMAP(rxch_free, MAX_RXCH);

	/* pasemi_read_iob_reg - read IOB register
	* @reg: Register to read (offset into PCI CFG space)
	*/
	unsigned int pasemi_read_iob_reg(unsigned int reg)
	{
	return in_le32(iob_regs+reg);
	}
	EXPORT_SYMBOL(pasemi_read_iob_reg);

	/* pasemi_write_iob_reg - write IOB register
	* @reg: Register to write to (offset into PCI CFG space)
	* @val: Value to write
	*/
	void pasemi_write_iob_reg(unsigned int reg, unsigned int val)
	{
	out_le32(iob_regs+reg, val);
	}
	EXPORT_SYMBOL(pasemi_write_iob_reg);

	/* pasemi_read_mac_reg - read MAC register
	* @intf: MAC interface
	* @reg: Register to read (offset into PCI CFG space)
	*/
	unsigned int pasemi_read_mac_reg(int intf, unsigned int reg)
	{
	return in_le32(mac_regs[intf]+reg);
	}
	EXPORT_SYMBOL(pasemi_read_mac_reg);

	/* pasemi_write_mac_reg - write MAC register
	* @intf: MAC interface
	* @reg: Register to write to (offset into PCI CFG space)
	* @val: Value to write
	*/
	void pasemi_write_mac_reg(int intf, unsigned int reg, unsigned int val)
	{
	out_le32(mac_regs[intf]+reg, val);
	}
	EXPORT_SYMBOL(pasemi_write_mac_reg);

	/* pasemi_read_dma_reg - read DMA register
	* @reg: Register to read (offset into PCI CFG space)
	*/
	unsigned int pasemi_read_dma_reg(unsigned int reg)
	{
	return in_le32(dma_regs+reg);
	}
	EXPORT_SYMBOL(pasemi_read_dma_reg);

	/* pasemi_write_dma_reg - write DMA register
	* @reg: Register to write to (offset into PCI CFG space)
	* @val: Value to write
	*/
	void pasemi_write_dma_reg(unsigned int reg, unsigned int val)
	{
	out_le32(dma_regs+reg, val);
	}
	EXPORT_SYMBOL(pasemi_write_dma_reg);

	static int pasemi_alloc_tx_chan(enum pasemi_dmachan_type type)
	{
	int bit;
	int start, limit;

	switch (type & (TXCHAN_EVT0\|TXCHAN_EVT1)) {
	case TXCHAN_EVT0:
	start = 0;
	limit = 10;
	break;
	case TXCHAN_EVT1:
	start = 10;
	limit = MAX_TXCH;
	break;
	default:
	start = 0;
	limit = MAX_TXCH;
	break;
	}
	retry:
	bit = find_next_bit(txch_free, MAX_TXCH, start);
	if (bit >= limit)
	return -ENOSPC;
	if (!test_and_clear_bit(bit, txch_free))
	goto retry;

	return bit;
	}

	static void pasemi_free_tx_chan(int chan)
	{
	BUG_ON(test_bit(chan, txch_free));
	set_bit(chan, txch_free);
	}

	static int pasemi_alloc_rx_chan(void)
	{
	int bit;
	retry:
	bit = find_first_bit(rxch_free, MAX_RXCH);
	if (bit >= MAX_TXCH)
	return -ENOSPC;
	if (!test_and_clear_bit(bit, rxch_free))
	goto retry;

	return bit;
	}

	static void pasemi_free_rx_chan(int chan)
	{
	BUG_ON(test_bit(chan, rxch_free));
	set_bit(chan, rxch_free);
	}

	/* pasemi_dma_alloc_chan - Allocate a DMA channel
	* @type: Type of channel to allocate
	* @total_size: Total size of structure to allocate (to allow for more
	* room behind the structure to be used by the client)
	* @offset: Offset in bytes from start of the total structure to the beginning
	* of struct pasemi_dmachan. Needed when struct pasemi_dmachan is
	* not the first member of the client structure.
	*
	* pasemi_dma_alloc_chan allocates a DMA channel for use by a client. The
	* type argument specifies whether it's a RX or TX channel, and in the case
	* of TX channels which group it needs to belong to (if any).
	*
	* Returns a pointer to the total structure allocated on success, NULL
	* on failure.
	*/
	void *pasemi_dma_alloc_chan(enum pasemi_dmachan_type type,
	int total_size, int offset)
	{
	void *buf;
	struct pasemi_dmachan *chan;
	int chno;

	BUG_ON(total_size < sizeof(struct pasemi_dmachan));

	buf = kzalloc(total_size, GFP_KERNEL);

	if (!buf)
	return NULL;
	chan = buf + offset;

	chan->priv = buf;

	switch (type & (TXCHAN\|RXCHAN)) {
	case RXCHAN:
	chno = pasemi_alloc_rx_chan();
	chan->chno = chno;
	chan->irq = irq_create_mapping(NULL,
	base_hw_irq + num_txch + chno);
	chan->status = &dma_status->rx_sta[chno];
	break;
	case TXCHAN:
	chno = pasemi_alloc_tx_chan(type);
	chan->chno = chno;
	chan->irq = irq_create_mapping(NULL, base_hw_irq + chno);
	chan->status = &dma_status->tx_sta[chno];
	break;
	}

	chan->chan_type = type;

	return chan;
	}
	EXPORT_SYMBOL(pasemi_dma_alloc_chan);

	/* pasemi_dma_free_chan - Free a previously allocated channel
	* @chan: Channel to free
	*
	* Frees a previously allocated channel. It will also deallocate any
	* descriptor ring associated with the channel, if allocated.
	*/
	void pasemi_dma_free_chan(struct pasemi_dmachan *chan)
	{
	if (chan->ring_virt)
	pasemi_dma_free_ring(chan);

	switch (chan->chan_type & (RXCHAN\|TXCHAN)) {
	case RXCHAN:
	pasemi_free_rx_chan(chan->chno);
	break;
	case TXCHAN:
	pasemi_free_tx_chan(chan->chno);
	break;
	}

	kfree(chan->priv);
	}
	EXPORT_SYMBOL(pasemi_dma_free_chan);

	/* pasemi_dma_alloc_ring - Allocate descriptor ring for a channel
	* @chan: Channel for which to allocate
	* @ring_size: Ring size in 64-bit (8-byte) words
	*
	* Allocate a descriptor ring for a channel. Returns 0 on success, errno
	* on failure. The passed in struct pasemi_dmachan is updated with the
	* virtual and DMA addresses of the ring.
	*/
	int pasemi_dma_alloc_ring(struct pasemi_dmachan *chan, int ring_size)
	{
	BUG_ON(chan->ring_virt);

	chan->ring_size = ring_size;

	chan->ring_virt = dma_alloc_coherent(&dma_pdev->dev,
	ring_size * sizeof(u64),
	&chan->ring_dma, GFP_KERNEL);

	if (!chan->ring_virt)
	return -ENOMEM;

	memset(chan->ring_virt, 0, ring_size * sizeof(u64));

	return 0;
	}
	EXPORT_SYMBOL(pasemi_dma_alloc_ring);

	/* pasemi_dma_free_ring - Free an allocated descriptor ring for a channel
	* @chan: Channel for which to free the descriptor ring
	*
	* Frees a previously allocated descriptor ring for a channel.
	*/
	void pasemi_dma_free_ring(struct pasemi_dmachan *chan)
	{
	BUG_ON(!chan->ring_virt);

	dma_free_coherent(&dma_pdev->dev, chan->ring_size * sizeof(u64),
	chan->ring_virt, chan->ring_dma);
	chan->ring_virt = NULL;
	chan->ring_size = 0;
	chan->ring_dma = 0;
	}
	EXPORT_SYMBOL(pasemi_dma_free_ring);

	/* pasemi_dma_start_chan - Start a DMA channel
	* @chan: Channel to start
	* @cmdsta: Additional CCMDSTA/TCMDSTA bits to write
	*
	* Enables (starts) a DMA channel with optional additional arguments.
	*/
	void pasemi_dma_start_chan(const struct pasemi_dmachan *chan, const u32 cmdsta)
	{
	if (chan->chan_type == RXCHAN)
	pasemi_write_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(chan->chno),
	cmdsta \| PAS_DMA_RXCHAN_CCMDSTA_EN);
	else
	pasemi_write_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(chan->chno),
	cmdsta \| PAS_DMA_TXCHAN_TCMDSTA_EN);
	}
	EXPORT_SYMBOL(pasemi_dma_start_chan);

	/* pasemi_dma_stop_chan - Stop a DMA channel
	* @chan: Channel to stop
	*
	* Stops (disables) a DMA channel. This is done by setting the ST bit in the
	* CMDSTA register and waiting on the ACT (active) bit to clear, then
	* finally disabling the whole channel.
	*
	* This function will only try for a short while for the channel to stop, if
	* it doesn't it will return failure.
	*
	* Returns 1 on success, 0 on failure.
	*/
	#define MAX_RETRIES 5000
	int pasemi_dma_stop_chan(const struct pasemi_dmachan *chan)
	{
	int reg, retries;
	u32 sta;

	if (chan->chan_type == RXCHAN) {
	reg = PAS_DMA_RXCHAN_CCMDSTA(chan->chno);
	pasemi_write_dma_reg(reg, PAS_DMA_RXCHAN_CCMDSTA_ST);
	for (retries = 0; retries < MAX_RETRIES; retries++) {
	sta = pasemi_read_dma_reg(reg);
	if (!(sta & PAS_DMA_RXCHAN_CCMDSTA_ACT)) {
	pasemi_write_dma_reg(reg, 0);
	return 1;
	}
	cond_resched();
	}
	} else {
	reg = PAS_DMA_TXCHAN_TCMDSTA(chan->chno);
	pasemi_write_dma_reg(reg, PAS_DMA_TXCHAN_TCMDSTA_ST);
	for (retries = 0; retries < MAX_RETRIES; retries++) {
	sta = pasemi_read_dma_reg(reg);
	if (!(sta & PAS_DMA_TXCHAN_TCMDSTA_ACT)) {
	pasemi_write_dma_reg(reg, 0);
	return 1;
	}
	cond_resched();
	}
	}

	return 0;
	}
	EXPORT_SYMBOL(pasemi_dma_stop_chan);

	/* pasemi_dma_alloc_buf - Allocate a buffer to use for DMA
	* @chan: Channel to allocate for
	* @size: Size of buffer in bytes
	* @handle: DMA handle
	*
	* Allocate a buffer to be used by the DMA engine for read/write,
	* similar to dma_alloc_coherent().
	*
	* Returns the virtual address of the buffer, or NULL in case of failure.
	*/
	void pasemi_dma_alloc_buf(struct pasemi_dmachan chan, int size,
	dma_addr_t *handle)
	{
	return dma_alloc_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
	}
	EXPORT_SYMBOL(pasemi_dma_alloc_buf);

	/* pasemi_dma_free_buf - Free a buffer used for DMA
	* @chan: Channel the buffer was allocated for
	* @size: Size of buffer in bytes
	* @handle: DMA handle
	*
	* Frees a previously allocated buffer.
	*/
	void pasemi_dma_free_buf(struct pasemi_dmachan *chan, int size,
	dma_addr_t *handle)
	{
	dma_free_coherent(&dma_pdev->dev, size, handle, GFP_KERNEL);
	}
	EXPORT_SYMBOL(pasemi_dma_free_buf);

	static void map_onedev(struct pci_dev p, int index)
	{
	struct device_node *dn;
	void __iomem *ret;

	dn = pci_device_to_OF_node(p);
	if (!dn)
	goto fallback;

	ret = of_iomap(dn, index);
	if (!ret)
	goto fallback;

	return ret;
	fallback:
	/* This is hardcoded and ugly, but we have some firmware versions
	* that don't provide the register space in the device tree. Luckily
	* they are at well-known locations so we can just do the math here.
	*/
	return ioremap(0xe0000000 + (p->devfn << 12), 0x2000);
	}

	/* pasemi_dma_init - Initialize the PA Semi DMA library
	*
	* This function initializes the DMA library. It must be called before
	* any other function in the library.
	*
	* Returns 0 on success, errno on failure.
	*/
	int pasemi_dma_init(void)
	{
	static spinlock_t init_lock = SPIN_LOCK_UNLOCKED;
	struct pci_dev *iob_pdev;
	struct pci_dev *pdev;
	struct resource res;
	struct device_node *dn;
	int i, intf, err = 0;
	unsigned long timeout;
	u32 tmp;

	if (!machine_is(pasemi))
	return -ENODEV;

	spin_lock(&init_lock);

	/* Make sure we haven't already initialized */
	if (dma_pdev)
	goto out;

	iob_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa001, NULL);
	if (!iob_pdev) {
	BUG();
	printk(KERN_WARNING "Can't find I/O Bridge\n");
	err = -ENODEV;
	goto out;
	}
	iob_regs = map_onedev(iob_pdev, 0);

	dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
	if (!dma_pdev) {
	BUG();
	printk(KERN_WARNING "Can't find DMA controller\n");
	err = -ENODEV;
	goto out;
	}
	dma_regs = map_onedev(dma_pdev, 0);
	base_hw_irq = virq_to_hw(dma_pdev->irq);

	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_TXCH, &tmp);
	num_txch = (tmp & PAS_DMA_CAP_TXCH_TCHN_M) >> PAS_DMA_CAP_TXCH_TCHN_S;

	pci_read_config_dword(dma_pdev, PAS_DMA_CAP_RXCH, &tmp);
	num_rxch = (tmp & PAS_DMA_CAP_RXCH_RCHN_M) >> PAS_DMA_CAP_RXCH_RCHN_S;

	intf = 0;
	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, NULL);
	pdev;
	pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa006, pdev))
	mac_regs[intf++] = map_onedev(pdev, 0);

	pci_dev_put(pdev);

	for (pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, NULL);
	pdev;
	pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa005, pdev))
	mac_regs[intf++] = map_onedev(pdev, 0);

	pci_dev_put(pdev);

	dn = pci_device_to_OF_node(iob_pdev);
	if (dn)
	err = of_address_to_resource(dn, 1, &res);
	if (!dn \|\| err) {
	/* Fallback for old firmware */
	res.start = 0xfd800000;
	res.end = res.start + 0x1000;
	}
	dma_status = __ioremap(res.start, res.end-res.start, 0);
	pci_dev_put(iob_pdev);

	for (i = 0; i < MAX_TXCH; i++)
	__set_bit(i, txch_free);

	for (i = 0; i < MAX_RXCH; i++)
	__set_bit(i, rxch_free);

	timeout = jiffies + HZ;
	pasemi_write_dma_reg(PAS_DMA_COM_RXCMD, 0);
	while (pasemi_read_dma_reg(PAS_DMA_COM_RXSTA) & 1) {
	if (time_after(jiffies, timeout)) {
	pr_warning("Warning: Could not disable RX section\n");
	break;
	}
	}

	timeout = jiffies + HZ;
	pasemi_write_dma_reg(PAS_DMA_COM_TXCMD, 0);
	while (pasemi_read_dma_reg(PAS_DMA_COM_TXSTA) & 1) {
	if (time_after(jiffies, timeout)) {
	pr_warning("Warning: Could not disable TX section\n");
	break;
	}
	}

	/* setup resource allocations for the different DMA sections */
	tmp = pasemi_read_dma_reg(PAS_DMA_COM_CFG);
	pasemi_write_dma_reg(PAS_DMA_COM_CFG, tmp \| 0x18000000);

	/* enable tx section */
	pasemi_write_dma_reg(PAS_DMA_COM_TXCMD, PAS_DMA_COM_TXCMD_EN);

	/* enable rx section */
	pasemi_write_dma_reg(PAS_DMA_COM_RXCMD, PAS_DMA_COM_RXCMD_EN);

	printk(KERN_INFO "PA Semi PWRficient DMA library initialized "
	"(%d tx, %d rx channels)\n", num_txch, num_rxch);

	out:
	spin_unlock(&init_lock);
	return err;
	}
	EXPORT_SYMBOL(pasemi_dma_init);