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path: root/drivers/net/ethernet/altera/altera_sgdma.c
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Diffstat (limited to 'drivers/net/ethernet/altera/altera_sgdma.c')
-rw-r--r--drivers/net/ethernet/altera/altera_sgdma.c527
1 files changed, 527 insertions, 0 deletions
diff --git a/drivers/net/ethernet/altera/altera_sgdma.c b/drivers/net/ethernet/altera/altera_sgdma.c
new file mode 100644
index 000000000..7f247ccbe
--- /dev/null
+++ b/drivers/net/ethernet/altera/altera_sgdma.c
@@ -0,0 +1,527 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Altera TSE SGDMA and MSGDMA Linux driver
+ * Copyright (C) 2014 Altera Corporation. All rights reserved
+ */
+
+#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;
+
+ 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,
+ SGDMA_DESC_LEN,
+ 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,
+ SGDMA_DESC_LEN,
+ 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,
+ SGDMA_DESC_LEN, 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 transaction 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-31 16:44:42 +0000