diff options
Diffstat (limited to 'kernel/drivers/net/ethernet/altera/altera_sgdma.c')
| -rw-r--r-- | kernel/drivers/net/ethernet/altera/altera_sgdma.c | 540 |
1 files changed, 540 insertions, 0 deletions
diff --git a/kernel/drivers/net/ethernet/altera/altera_sgdma.c b/kernel/drivers/net/ethernet/altera/altera_sgdma.c new file mode 100644 index 000000000..580553d42 --- /dev/null +++ b/kernel/drivers/net/ethernet/altera/altera_sgdma.c @@ -0,0 +1,540 @@ +/* Altera TSE SGDMA and MSGDMA Linux driver + * Copyright (C) 2014 Altera Corporation. All rights reserved + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/list.h> +#include "altera_utils.h" +#include "altera_tse.h" +#include "altera_sgdmahw.h" +#include "altera_sgdma.h" + +static void sgdma_setup_descrip(struct sgdma_descrip __iomem *desc, + struct sgdma_descrip __iomem *ndesc, + dma_addr_t ndesc_phys, + dma_addr_t raddr, + dma_addr_t waddr, + u16 length, + int generate_eop, + int rfixed, + int wfixed); + +static int sgdma_async_write(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc); + +static int sgdma_async_read(struct altera_tse_private *priv); + +static dma_addr_t +sgdma_txphysaddr(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc); + +static dma_addr_t +sgdma_rxphysaddr(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc); + +static int sgdma_txbusy(struct altera_tse_private *priv); + +static int sgdma_rxbusy(struct altera_tse_private *priv); + +static void +queue_tx(struct altera_tse_private *priv, struct tse_buffer *buffer); + +static void +queue_rx(struct altera_tse_private *priv, struct tse_buffer *buffer); + +static struct tse_buffer * +dequeue_tx(struct altera_tse_private *priv); + +static struct tse_buffer * +dequeue_rx(struct altera_tse_private *priv); + +static struct tse_buffer * +queue_rx_peekhead(struct altera_tse_private *priv); + +int sgdma_initialize(struct altera_tse_private *priv) +{ + priv->txctrlreg = SGDMA_CTRLREG_ILASTD | + SGDMA_CTRLREG_INTEN; + + priv->rxctrlreg = SGDMA_CTRLREG_IDESCRIP | + SGDMA_CTRLREG_INTEN | + SGDMA_CTRLREG_ILASTD; + + priv->sgdmadesclen = sizeof(struct sgdma_descrip); + + INIT_LIST_HEAD(&priv->txlisthd); + INIT_LIST_HEAD(&priv->rxlisthd); + + priv->rxdescphys = (dma_addr_t) 0; + priv->txdescphys = (dma_addr_t) 0; + + priv->rxdescphys = dma_map_single(priv->device, + (void __force *)priv->rx_dma_desc, + priv->rxdescmem, DMA_BIDIRECTIONAL); + + if (dma_mapping_error(priv->device, priv->rxdescphys)) { + sgdma_uninitialize(priv); + netdev_err(priv->dev, "error mapping rx descriptor memory\n"); + return -EINVAL; + } + + priv->txdescphys = dma_map_single(priv->device, + (void __force *)priv->tx_dma_desc, + priv->txdescmem, DMA_TO_DEVICE); + + if (dma_mapping_error(priv->device, priv->txdescphys)) { + sgdma_uninitialize(priv); + netdev_err(priv->dev, "error mapping tx descriptor memory\n"); + return -EINVAL; + } + + /* Initialize descriptor memory to all 0's, sync memory to cache */ + memset_io(priv->tx_dma_desc, 0, priv->txdescmem); + memset_io(priv->rx_dma_desc, 0, priv->rxdescmem); + + dma_sync_single_for_device(priv->device, priv->txdescphys, + priv->txdescmem, DMA_TO_DEVICE); + + dma_sync_single_for_device(priv->device, priv->rxdescphys, + priv->rxdescmem, DMA_TO_DEVICE); + + return 0; +} + +void sgdma_uninitialize(struct altera_tse_private *priv) +{ + if (priv->rxdescphys) + dma_unmap_single(priv->device, priv->rxdescphys, + priv->rxdescmem, DMA_BIDIRECTIONAL); + + if (priv->txdescphys) + dma_unmap_single(priv->device, priv->txdescphys, + priv->txdescmem, DMA_TO_DEVICE); +} + +/* This function resets the SGDMA controller and clears the + * descriptor memory used for transmits and receives. + */ +void sgdma_reset(struct altera_tse_private *priv) +{ + /* Initialize descriptor memory to 0 */ + memset_io(priv->tx_dma_desc, 0, priv->txdescmem); + memset_io(priv->rx_dma_desc, 0, priv->rxdescmem); + + csrwr32(SGDMA_CTRLREG_RESET, priv->tx_dma_csr, sgdma_csroffs(control)); + csrwr32(0, priv->tx_dma_csr, sgdma_csroffs(control)); + + csrwr32(SGDMA_CTRLREG_RESET, priv->rx_dma_csr, sgdma_csroffs(control)); + csrwr32(0, priv->rx_dma_csr, sgdma_csroffs(control)); +} + +/* For SGDMA, interrupts remain enabled after initially enabling, + * so no need to provide implementations for abstract enable + * and disable + */ + +void sgdma_enable_rxirq(struct altera_tse_private *priv) +{ +} + +void sgdma_enable_txirq(struct altera_tse_private *priv) +{ +} + +void sgdma_disable_rxirq(struct altera_tse_private *priv) +{ +} + +void sgdma_disable_txirq(struct altera_tse_private *priv) +{ +} + +void sgdma_clear_rxirq(struct altera_tse_private *priv) +{ + tse_set_bit(priv->rx_dma_csr, sgdma_csroffs(control), + SGDMA_CTRLREG_CLRINT); +} + +void sgdma_clear_txirq(struct altera_tse_private *priv) +{ + tse_set_bit(priv->tx_dma_csr, sgdma_csroffs(control), + SGDMA_CTRLREG_CLRINT); +} + +/* transmits buffer through SGDMA. Returns number of buffers + * transmitted, 0 if not possible. + * + * tx_lock is held by the caller + */ +int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) +{ + struct sgdma_descrip __iomem *descbase = + (struct sgdma_descrip __iomem *)priv->tx_dma_desc; + + struct sgdma_descrip __iomem *cdesc = &descbase[0]; + struct sgdma_descrip __iomem *ndesc = &descbase[1]; + + /* wait 'til the tx sgdma is ready for the next transmit request */ + if (sgdma_txbusy(priv)) + return 0; + + sgdma_setup_descrip(cdesc, /* current descriptor */ + ndesc, /* next descriptor */ + sgdma_txphysaddr(priv, ndesc), + buffer->dma_addr, /* address of packet to xmit */ + 0, /* write addr 0 for tx dma */ + buffer->len, /* length of packet */ + SGDMA_CONTROL_EOP, /* Generate EOP */ + 0, /* read fixed */ + SGDMA_CONTROL_WR_FIXED); /* Generate SOP */ + + sgdma_async_write(priv, cdesc); + + /* enqueue the request to the pending transmit queue */ + queue_tx(priv, buffer); + + return 1; +} + + +/* tx_lock held to protect access to queued tx list + */ +u32 sgdma_tx_completions(struct altera_tse_private *priv) +{ + u32 ready = 0; + + if (!sgdma_txbusy(priv) && + ((csrrd8(priv->tx_dma_desc, sgdma_descroffs(control)) + & SGDMA_CONTROL_HW_OWNED) == 0) && + (dequeue_tx(priv))) { + ready = 1; + } + + return ready; +} + +void sgdma_start_rxdma(struct altera_tse_private *priv) +{ + sgdma_async_read(priv); +} + +void sgdma_add_rx_desc(struct altera_tse_private *priv, + struct tse_buffer *rxbuffer) +{ + queue_rx(priv, rxbuffer); +} + +/* status is returned on upper 16 bits, + * length is returned in lower 16 bits + */ +u32 sgdma_rx_status(struct altera_tse_private *priv) +{ + struct sgdma_descrip __iomem *base = + (struct sgdma_descrip __iomem *)priv->rx_dma_desc; + struct sgdma_descrip __iomem *desc = NULL; + struct tse_buffer *rxbuffer = NULL; + unsigned int rxstatus = 0; + + u32 sts = csrrd32(priv->rx_dma_csr, sgdma_csroffs(status)); + + desc = &base[0]; + if (sts & SGDMA_STSREG_EOP) { + unsigned int pktlength = 0; + unsigned int pktstatus = 0; + dma_sync_single_for_cpu(priv->device, + priv->rxdescphys, + priv->sgdmadesclen, + DMA_FROM_DEVICE); + + pktlength = csrrd16(desc, sgdma_descroffs(bytes_xferred)); + pktstatus = csrrd8(desc, sgdma_descroffs(status)); + rxstatus = pktstatus & ~SGDMA_STATUS_EOP; + rxstatus = rxstatus << 16; + rxstatus |= (pktlength & 0xffff); + + if (rxstatus) { + csrwr8(0, desc, sgdma_descroffs(status)); + + rxbuffer = dequeue_rx(priv); + if (rxbuffer == NULL) + netdev_info(priv->dev, + "sgdma rx and rx queue empty!\n"); + + /* Clear control */ + csrwr32(0, priv->rx_dma_csr, sgdma_csroffs(control)); + /* clear status */ + csrwr32(0xf, priv->rx_dma_csr, sgdma_csroffs(status)); + + /* kick the rx sgdma after reaping this descriptor */ + sgdma_async_read(priv); + + } else { + /* If the SGDMA indicated an end of packet on recv, + * then it's expected that the rxstatus from the + * descriptor is non-zero - meaning a valid packet + * with a nonzero length, or an error has been + * indicated. if not, then all we can do is signal + * an error and return no packet received. Most likely + * there is a system design error, or an error in the + * underlying kernel (cache or cache management problem) + */ + netdev_err(priv->dev, + "SGDMA RX Error Info: %x, %x, %x\n", + sts, csrrd8(desc, sgdma_descroffs(status)), + rxstatus); + } + } else if (sts == 0) { + sgdma_async_read(priv); + } + + return rxstatus; +} + + +/* Private functions */ +static void sgdma_setup_descrip(struct sgdma_descrip __iomem *desc, + struct sgdma_descrip __iomem *ndesc, + dma_addr_t ndesc_phys, + dma_addr_t raddr, + dma_addr_t waddr, + u16 length, + int generate_eop, + int rfixed, + int wfixed) +{ + /* Clear the next descriptor as not owned by hardware */ + + u32 ctrl = csrrd8(ndesc, sgdma_descroffs(control)); + ctrl &= ~SGDMA_CONTROL_HW_OWNED; + csrwr8(ctrl, ndesc, sgdma_descroffs(control)); + + ctrl = SGDMA_CONTROL_HW_OWNED; + ctrl |= generate_eop; + ctrl |= rfixed; + ctrl |= wfixed; + + /* Channel is implicitly zero, initialized to 0 by default */ + csrwr32(lower_32_bits(raddr), desc, sgdma_descroffs(raddr)); + csrwr32(lower_32_bits(waddr), desc, sgdma_descroffs(waddr)); + + csrwr32(0, desc, sgdma_descroffs(pad1)); + csrwr32(0, desc, sgdma_descroffs(pad2)); + csrwr32(lower_32_bits(ndesc_phys), desc, sgdma_descroffs(next)); + + csrwr8(ctrl, desc, sgdma_descroffs(control)); + csrwr8(0, desc, sgdma_descroffs(status)); + csrwr8(0, desc, sgdma_descroffs(wburst)); + csrwr8(0, desc, sgdma_descroffs(rburst)); + csrwr16(length, desc, sgdma_descroffs(bytes)); + csrwr16(0, desc, sgdma_descroffs(bytes_xferred)); +} + +/* If hardware is busy, don't restart async read. + * if status register is 0 - meaning initial state, restart async read, + * probably for the first time when populating a receive buffer. + * If read status indicate not busy and a status, restart the async + * DMA read. + */ +static int sgdma_async_read(struct altera_tse_private *priv) +{ + struct sgdma_descrip __iomem *descbase = + (struct sgdma_descrip __iomem *)priv->rx_dma_desc; + + struct sgdma_descrip __iomem *cdesc = &descbase[0]; + struct sgdma_descrip __iomem *ndesc = &descbase[1]; + struct tse_buffer *rxbuffer = NULL; + + if (!sgdma_rxbusy(priv)) { + rxbuffer = queue_rx_peekhead(priv); + if (rxbuffer == NULL) { + netdev_err(priv->dev, "no rx buffers available\n"); + return 0; + } + + sgdma_setup_descrip(cdesc, /* current descriptor */ + ndesc, /* next descriptor */ + sgdma_rxphysaddr(priv, ndesc), + 0, /* read addr 0 for rx dma */ + rxbuffer->dma_addr, /* write addr for rx dma */ + 0, /* read 'til EOP */ + 0, /* EOP: NA for rx dma */ + 0, /* read fixed: NA for rx dma */ + 0); /* SOP: NA for rx DMA */ + + dma_sync_single_for_device(priv->device, + priv->rxdescphys, + priv->sgdmadesclen, + DMA_TO_DEVICE); + + csrwr32(lower_32_bits(sgdma_rxphysaddr(priv, cdesc)), + priv->rx_dma_csr, + sgdma_csroffs(next_descrip)); + + csrwr32((priv->rxctrlreg | SGDMA_CTRLREG_START), + priv->rx_dma_csr, + sgdma_csroffs(control)); + + return 1; + } + + return 0; +} + +static int sgdma_async_write(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc) +{ + if (sgdma_txbusy(priv)) + return 0; + + /* clear control and status */ + csrwr32(0, priv->tx_dma_csr, sgdma_csroffs(control)); + csrwr32(0x1f, priv->tx_dma_csr, sgdma_csroffs(status)); + + dma_sync_single_for_device(priv->device, priv->txdescphys, + priv->sgdmadesclen, DMA_TO_DEVICE); + + csrwr32(lower_32_bits(sgdma_txphysaddr(priv, desc)), + priv->tx_dma_csr, + sgdma_csroffs(next_descrip)); + + csrwr32((priv->txctrlreg | SGDMA_CTRLREG_START), + priv->tx_dma_csr, + sgdma_csroffs(control)); + + return 1; +} + +static dma_addr_t +sgdma_txphysaddr(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc) +{ + dma_addr_t paddr = priv->txdescmem_busaddr; + uintptr_t offs = (uintptr_t)desc - (uintptr_t)priv->tx_dma_desc; + return (dma_addr_t)((uintptr_t)paddr + offs); +} + +static dma_addr_t +sgdma_rxphysaddr(struct altera_tse_private *priv, + struct sgdma_descrip __iomem *desc) +{ + dma_addr_t paddr = priv->rxdescmem_busaddr; + uintptr_t offs = (uintptr_t)desc - (uintptr_t)priv->rx_dma_desc; + return (dma_addr_t)((uintptr_t)paddr + offs); +} + +#define list_remove_head(list, entry, type, member) \ + do { \ + entry = NULL; \ + if (!list_empty(list)) { \ + entry = list_entry((list)->next, type, member); \ + list_del_init(&entry->member); \ + } \ + } while (0) + +#define list_peek_head(list, entry, type, member) \ + do { \ + entry = NULL; \ + if (!list_empty(list)) { \ + entry = list_entry((list)->next, type, member); \ + } \ + } while (0) + +/* adds a tse_buffer to the tail of a tx buffer list. + * assumes the caller is managing and holding a mutual exclusion + * primitive to avoid simultaneous pushes/pops to the list. + */ +static void +queue_tx(struct altera_tse_private *priv, struct tse_buffer *buffer) +{ + list_add_tail(&buffer->lh, &priv->txlisthd); +} + + +/* adds a tse_buffer to the tail of a rx buffer list + * assumes the caller is managing and holding a mutual exclusion + * primitive to avoid simultaneous pushes/pops to the list. + */ +static void +queue_rx(struct altera_tse_private *priv, struct tse_buffer *buffer) +{ + list_add_tail(&buffer->lh, &priv->rxlisthd); +} + +/* dequeues a tse_buffer from the transmit buffer list, otherwise + * returns NULL if empty. + * assumes the caller is managing and holding a mutual exclusion + * primitive to avoid simultaneous pushes/pops to the list. + */ +static struct tse_buffer * +dequeue_tx(struct altera_tse_private *priv) +{ + struct tse_buffer *buffer = NULL; + list_remove_head(&priv->txlisthd, buffer, struct tse_buffer, lh); + return buffer; +} + +/* dequeues a tse_buffer from the receive buffer list, otherwise + * returns NULL if empty + * assumes the caller is managing and holding a mutual exclusion + * primitive to avoid simultaneous pushes/pops to the list. + */ +static struct tse_buffer * +dequeue_rx(struct altera_tse_private *priv) +{ + struct tse_buffer *buffer = NULL; + list_remove_head(&priv->rxlisthd, buffer, struct tse_buffer, lh); + return buffer; +} + +/* dequeues a tse_buffer from the receive buffer list, otherwise + * returns NULL if empty + * assumes the caller is managing and holding a mutual exclusion + * primitive to avoid simultaneous pushes/pops to the list while the + * head is being examined. + */ +static struct tse_buffer * +queue_rx_peekhead(struct altera_tse_private *priv) +{ + struct tse_buffer *buffer = NULL; + list_peek_head(&priv->rxlisthd, buffer, struct tse_buffer, lh); + return buffer; +} + +/* check and return rx sgdma status without polling + */ +static int sgdma_rxbusy(struct altera_tse_private *priv) +{ + return csrrd32(priv->rx_dma_csr, sgdma_csroffs(status)) + & SGDMA_STSREG_BUSY; +} + +/* waits for the tx sgdma to finish it's current operation, returns 0 + * when it transitions to nonbusy, returns 1 if the operation times out + */ +static int sgdma_txbusy(struct altera_tse_private *priv) +{ + int delay = 0; + + /* if DMA is busy, wait for current transactino to finish */ + while ((csrrd32(priv->tx_dma_csr, sgdma_csroffs(status)) + & SGDMA_STSREG_BUSY) && (delay++ < 100)) + udelay(1); + + if (csrrd32(priv->tx_dma_csr, sgdma_csroffs(status)) + & SGDMA_STSREG_BUSY) { + netdev_err(priv->dev, "timeout waiting for tx dma\n"); + return 1; + } + return 0; +} |