diff options
author | Olof Johansson <olof@lixom.net> | 2007-11-29 02:56:20 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-01-28 23:04:21 (GMT) |
commit | 8ee9d85779356c1dc2ba87aca27fbf9414f2d82b (patch) | |
tree | 8054bf7c755e47a41af33b59f344c237b5b20282 /arch/powerpc/platforms/pasemi/dma_lib.c | |
parent | 40afa5315823761b174926235dc38be24dc3ea63 (diff) | |
download | linux-fsl-qoriq-8ee9d85779356c1dc2ba87aca27fbf9414f2d82b.tar.xz |
pasemi: DMA engine management library
pasemi: DMA engine management library
Introduce a DMA management library to manage the various DMA resources
on the PA Semi SoCs. Since several drivers need to allocate these shared
resources, provide some abstractions as well as allocation/free functions
for channels, etc.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'arch/powerpc/platforms/pasemi/dma_lib.c')
-rw-r--r-- | arch/powerpc/platforms/pasemi/dma_lib.c | 487 |
1 files changed, 487 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pasemi/dma_lib.c b/arch/powerpc/platforms/pasemi/dma_lib.c new file mode 100644 index 0000000..e6e4742 --- /dev/null +++ b/arch/powerpc/platforms/pasemi/dma_lib.c @@ -0,0 +1,487 @@ +/* + * 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/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; + 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); + + 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; +} |