sysadmin/ipxe
1
0
Fork 0
mirror of https://github.com/ipxe/ipxe synced 2026-04-16 03:00:10 +03:00
Code Issues Packages Projects Releases Wiki Activity

[dma] Move I/O buffer DMA operations to iobuf.h

Browse Source 
Include a potential DMA mapping within the definition of an I/O
buffer, and move all I/O buffer DMA mapping functions from dma.h to
iobuf.h.  This avoids the need for drivers to maintain a separate list
of DMA mappings for each I/O buffer that they may handle.

Network device drivers typically do not keep track of transmit I/O
buffers, since the network device core already maintains a transmit
queue.  Drivers will typically call netdev_tx_complete_next() to
complete a transmission without first obtaining the relevant I/O
buffer pointer (and will rely on the network device core automatically
cancelling any pending transmissions when the device is closed).

To allow this driver design approach to be retained, update the
netdev_tx_complete() family of functions to automatically perform the
DMA unmapping operation if required.  For symmetry, also update the
netdev_rx() family of functions to behave the same way.

As a further convenience for drivers, allow the network device core to
automatically perform DMA mapping on the transmit datapath before
calling the driver's transmit() method.  This avoids the need to
introduce a mapping error handling code path into the typically
error-free transmit methods.

With these changes, the modifications required to update a typical
network device driver to use the new DMA API are fairly minimal:

- Allocate and free descriptor rings and similar coherent structures
  using dma_alloc()/dma_free() rather than malloc_phys()/free_phys()

- Allocate and free receive buffers using alloc_rx_iob()/free_rx_iob()
  rather than alloc_iob()/free_iob()

- Calculate DMA addresses using dma() or iob_dma() rather than
  virt_to_bus()

- Set a 64-bit DMA mask if needed using dma_set_mask_64bit() and
  thereafter eliminate checks on DMA address ranges

- Either record the DMA device in netdev->dma, or call iob_map_tx() as
  part of the transmit() method

- Ensure that debug messages use virt_to_phys() when displaying
  "hardware" addresses

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2020-11-26 12:25:02 +00:00
parent 70e6e83243
commit 8d337ecdae
16 changed files with 342 additions and 391 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/drivers/net/realtek.c
+42 -59
View File
@@ -621,7 +621,6 @@ static void realtek_destroy_ring ( struct realtek_nic *rtl,
static void realtek_refill_rx ( struct realtek_nic *rtl ) {
struct realtek_descriptor *rx;
struct io_buffer *iobuf;
struct dma_mapping *map;
unsigned int rx_idx;
int is_last;
@@ -629,34 +628,32 @@ static void realtek_refill_rx ( struct realtek_nic *rtl ) {
if ( rtl->legacy )
return;
while ( ( rtl->rx.ring.prod - rtl->rx.ring.cons ) < RTL_NUM_RX_DESC ) {
/* Get next receive descriptor */
rx_idx = ( rtl->rx.ring.prod % RTL_NUM_RX_DESC );
is_last = ( rx_idx == ( RTL_NUM_RX_DESC - 1 ) );
rx = &rtl->rx.ring.desc[rx_idx];
map = &rtl->rx.map[rx_idx];
assert ( rtl->rx.iobuf[rx_idx] == NULL );
while ( ( rtl->rx.prod - rtl->rx.cons ) < RTL_NUM_RX_DESC ) {
/* Allocate I/O buffer */
iobuf = dma_alloc_rx_iob ( rtl->dma, map, RTL_RX_MAX_LEN );
iobuf = alloc_rx_iob ( RTL_RX_MAX_LEN, rtl->dma );
if ( ! iobuf ) {
/* Wait for next refill */
return;
}
rtl->rx.iobuf[rx_idx] = iobuf;
/* Update producer index */
rtl->rx.ring.prod++;
/* Get next receive descriptor */
rx_idx = ( rtl->rx.prod++ % RTL_NUM_RX_DESC );
is_last = ( rx_idx == ( RTL_NUM_RX_DESC - 1 ) );
rx = &rtl->rx.desc[rx_idx];
/* Populate receive descriptor */
rx->address = cpu_to_le64 ( dma ( map, iobuf->data ) );
rx->address = cpu_to_le64 ( iob_dma ( iobuf ) );
rx->length = cpu_to_le16 ( RTL_RX_MAX_LEN );
wmb();
rx->flags = ( cpu_to_le16 ( RTL_DESC_OWN ) |
( is_last ? cpu_to_le16 ( RTL_DESC_EOR ) : 0 ) );
wmb();
/* Record I/O buffer */
assert ( rtl->rx_iobuf[rx_idx] == NULL );
rtl->rx_iobuf[rx_idx] = iobuf;
DBGC2 ( rtl, "REALTEK %p RX %d is [%lx,%lx)\n",
rtl, rx_idx, virt_to_phys ( iobuf->data ),
( virt_to_phys ( iobuf->data ) + RTL_RX_MAX_LEN ) );
@@ -676,11 +673,11 @@ static int realtek_open ( struct net_device *netdev ) {
int rc;
/* Create transmit descriptor ring */
if ( ( rc = realtek_create_ring ( rtl, &rtl->tx.ring ) ) != 0 )
if ( ( rc = realtek_create_ring ( rtl, &rtl->tx ) ) != 0 )
goto err_create_tx;
/* Create receive descriptor ring */
if ( ( rc = realtek_create_ring ( rtl, &rtl->rx.ring ) ) != 0 )
if ( ( rc = realtek_create_ring ( rtl, &rtl->rx ) ) != 0 )
goto err_create_rx;
/* Create receive buffer */
@@ -721,9 +718,9 @@ static int realtek_open ( struct net_device *netdev ) {
realtek_destroy_buffer ( rtl );
err_create_buffer:
realtek_destroy_ring ( rtl, &rtl->rx.ring );
realtek_destroy_ring ( rtl, &rtl->rx );
err_create_rx:
realtek_destroy_ring ( rtl, &rtl->tx.ring );
realtek_destroy_ring ( rtl, &rtl->tx );
err_create_tx:
return rc;
}
@@ -744,23 +741,17 @@ static void realtek_close ( struct net_device *netdev ) {
realtek_destroy_buffer ( rtl );
/* Destroy receive descriptor ring */
realtek_destroy_ring ( rtl, &rtl->rx.ring );
realtek_destroy_ring ( rtl, &rtl->rx );
/* Discard any unused receive buffers */
for ( i = 0 ; i < RTL_NUM_RX_DESC ; i++ ) {
if ( rtl->rx.iobuf[i] ) {
dma_unmap ( &rtl->rx.map[i] );
free_iob ( rtl->rx.iobuf[i] );
}
rtl->rx.iobuf[i] = NULL;
if ( rtl->rx_iobuf[i] )
free_rx_iob ( rtl->rx_iobuf[i] );
rtl->rx_iobuf[i] = NULL;
}
/* Unmap any incomplete transmit buffers */
for ( i = rtl->tx.ring.cons ; i != rtl->tx.ring.prod ; i++ )
dma_unmap ( &rtl->tx.map[ i % RTL_NUM_TX_DESC ] );
/* Destroy transmit descriptor ring */
realtek_destroy_ring ( rtl, &rtl->tx.ring );
realtek_destroy_ring ( rtl, &rtl->tx );
/* Reset legacy transmit descriptor index, if applicable */
if ( rtl->legacy )
@@ -778,37 +769,33 @@ static int realtek_transmit ( struct net_device *netdev,
struct io_buffer *iobuf ) {
struct realtek_nic *rtl = netdev->priv;
struct realtek_descriptor *tx;
struct dma_mapping *map;
unsigned int tx_idx;
physaddr_t address;
int is_last;
int rc;
/* Get next transmit descriptor */
if ( ( rtl->tx.ring.prod - rtl->tx.ring.cons ) >= RTL_NUM_TX_DESC ) {
if ( ( rtl->tx.prod - rtl->tx.cons ) >= RTL_NUM_TX_DESC ) {
netdev_tx_defer ( netdev, iobuf );
return 0;
}
tx_idx = ( rtl->tx.ring.prod % RTL_NUM_TX_DESC );
map = &rtl->tx.map[tx_idx];
tx_idx = ( rtl->tx.prod % RTL_NUM_TX_DESC );
/* Pad and align packet, if needed */
if ( rtl->legacy )
iob_pad ( iobuf, ETH_ZLEN );
/* Map I/O buffer */
if ( ( rc = dma_map_tx_iob ( rtl->dma, map, iobuf ) ) != 0 )
if ( ( rc = iob_map_tx ( iobuf, rtl->dma ) ) != 0 )
return rc;
address = dma ( map, iobuf->data );
/* Update producer index */
rtl->tx.ring.prod++;
rtl->tx.prod++;
/* Transmit packet */
if ( rtl->legacy ) {
/* Add to transmit ring */
writel ( address, rtl->regs + RTL_TSAD ( tx_idx ) );
writel ( iob_dma ( iobuf ), rtl->regs + RTL_TSAD ( tx_idx ) );
writel ( ( RTL_TSD_ERTXTH_DEFAULT | iob_len ( iobuf ) ),
rtl->regs + RTL_TSD ( tx_idx ) );
@@ -816,8 +803,8 @@ static int realtek_transmit ( struct net_device *netdev,
/* Populate transmit descriptor */
is_last = ( tx_idx == ( RTL_NUM_TX_DESC - 1 ) );
tx = &rtl->tx.ring.desc[tx_idx];
tx->address = cpu_to_le64 ( address );
tx = &rtl->tx.desc[tx_idx];
tx->address = cpu_to_le64 ( iob_dma ( iobuf ) );
tx->length = cpu_to_le16 ( iob_len ( iobuf ) );
wmb();
tx->flags = ( cpu_to_le16 ( RTL_DESC_OWN | RTL_DESC_FS |
@@ -847,10 +834,10 @@ static void realtek_poll_tx ( struct net_device *netdev ) {
unsigned int tx_idx;
/* Check for completed packets */
while ( rtl->tx.ring.cons != rtl->tx.ring.prod ) {
while ( rtl->tx.cons != rtl->tx.prod ) {
/* Get next transmit descriptor */
tx_idx = ( rtl->tx.ring.cons % RTL_NUM_TX_DESC );
tx_idx = ( rtl->tx.cons % RTL_NUM_TX_DESC );
/* Stop if descriptor is still in use */
if ( rtl->legacy ) {
@@ -863,18 +850,15 @@ static void realtek_poll_tx ( struct net_device *netdev ) {
} else {
/* Check ownership bit in descriptor */
tx = &rtl->tx.ring.desc[tx_idx];
tx = &rtl->tx.desc[tx_idx];
if ( tx->flags & cpu_to_le16 ( RTL_DESC_OWN ) )
return;
}
DBGC2 ( rtl, "REALTEK %p TX %d complete\n", rtl, tx_idx );
/* Unmap I/O buffer */
dma_unmap ( &rtl->tx.map[tx_idx] );
/* Complete TX descriptor */
rtl->tx.ring.cons++;
rtl->tx.cons++;
netdev_tx_complete_next ( netdev );
}
}
@@ -954,22 +938,19 @@ static void realtek_poll_rx ( struct net_device *netdev ) {
}
/* Check for received packets */
while ( rtl->rx.ring.cons != rtl->rx.ring.prod ) {
while ( rtl->rx.cons != rtl->rx.prod ) {
/* Get next receive descriptor */
rx_idx = ( rtl->rx.ring.cons % RTL_NUM_RX_DESC );
rx = &rtl->rx.ring.desc[rx_idx];
rx_idx = ( rtl->rx.cons % RTL_NUM_RX_DESC );
rx = &rtl->rx.desc[rx_idx];
/* Stop if descriptor is still in use */
if ( rx->flags & cpu_to_le16 ( RTL_DESC_OWN ) )
return;
/* Unmap buffer */
dma_unmap ( &rtl->rx.map[rx_idx] );
/* Populate I/O buffer */
iobuf = rtl->rx.iobuf[rx_idx];
rtl->rx.iobuf[rx_idx] = NULL;
iobuf = rtl->rx_iobuf[rx_idx];
rtl->rx_iobuf[rx_idx] = NULL;
len = ( le16_to_cpu ( rx->length ) & RTL_DESC_SIZE_MASK );
iob_put ( iobuf, ( len - 4 /* strip CRC */ ) );
@@ -984,7 +965,7 @@ static void realtek_poll_rx ( struct net_device *netdev ) {
"%zd)\n", rtl, rx_idx, len );
netdev_rx ( netdev, iobuf );
}
rtl->rx.ring.cons++;
rtl->rx.cons++;
}
}
@@ -1128,9 +1109,8 @@ static int realtek_probe ( struct pci_device *pci ) {
pci_set_drvdata ( pci, netdev );
netdev->dev = &pci->dev;
memset ( rtl, 0, sizeof ( *rtl ) );
rtl->dma = &pci->dma;
realtek_init_ring ( &rtl->tx.ring, RTL_NUM_TX_DESC, RTL_TNPDS );
realtek_init_ring ( &rtl->rx.ring, RTL_NUM_RX_DESC, RTL_RDSAR );
realtek_init_ring ( &rtl->tx, RTL_NUM_TX_DESC, RTL_TNPDS );
realtek_init_ring ( &rtl->rx, RTL_NUM_RX_DESC, RTL_RDSAR );
/* Fix up PCI device */
adjust_pci_device ( pci );
@@ -1142,6 +1122,9 @@ static int realtek_probe ( struct pci_device *pci ) {
goto err_ioremap;
}
/* Configure DMA */
rtl->dma = &pci->dma;
/* Reset the NIC */
if ( ( rc = realtek_reset ( rtl ) ) != 0 )
goto err_reset;