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[dma] Modify DMA API to simplify calculation of medial addresses

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Redefine the value stored within a DMA mapping to be the offset
between physical addresses and DMA addresses within the mapped region.

Provide a dma() wrapper function to calculate the DMA address for any
pointer within a mapped region, thereby simplifying the use cases when
a device needs to be given addresses other than the region start
address.

On a platform using the "flat" DMA implementation the DMA offset for
any mapped region is always zero, with the result that dma_map() can
be optimised away completely and dma() reduces to a straightforward
call to virt_to_phys().

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2020-11-25 15:52:00 +00:00
parent 24ef743778
commit cf12a41703
7 changed files with 100 additions and 58 deletions
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src/drivers/net/realtek.c
+14 -13
View File
@@ -506,6 +506,7 @@ static void realtek_check_link ( struct net_device *netdev ) {
* @ret rc Return status code
*/
static int realtek_create_buffer ( struct realtek_nic *rtl ) {
struct realtek_rx_buffer *rxbuf = &rtl->rxbuf;
size_t len = ( RTL_RXBUF_LEN + RTL_RXBUF_PAD );
/* Do nothing unless in legacy mode */
@@ -513,17 +514,16 @@ static int realtek_create_buffer ( struct realtek_nic *rtl ) {
return 0;
/* Allocate buffer */
rtl->rxbuf.data = dma_alloc ( rtl->dma, len, RTL_RXBUF_ALIGN,
&rtl->rxbuf.map );
if ( ! rtl->rxbuf.data )
rxbuf->data = dma_alloc ( rtl->dma, len, RTL_RXBUF_ALIGN, &rxbuf->map );
if ( ! rxbuf->data )
return -ENOMEM;
/* Program buffer address */
writel ( rtl->rxbuf.map.addr, rtl->regs + RTL_RBSTART );
writel ( dma ( &rxbuf->map, rxbuf->data ), rtl->regs + RTL_RBSTART );
DBGC ( rtl, "REALTEK %p receive buffer is at [%08lx,%08lx,%08lx)\n",
rtl, virt_to_phys ( rtl->rxbuf.data ),
( virt_to_phys ( rtl->rxbuf.data ) + RTL_RXBUF_LEN ),
( virt_to_phys ( rtl->rxbuf.data ) + len ) );
rtl, virt_to_phys ( rxbuf->data ),
( virt_to_phys ( rxbuf->data ) + RTL_RXBUF_LEN ),
( virt_to_phys ( rxbuf->data ) + len ) );
return 0;
}
@@ -534,6 +534,7 @@ static int realtek_create_buffer ( struct realtek_nic *rtl ) {
* @v rtl Realtek device
*/
static void realtek_destroy_buffer ( struct realtek_nic *rtl ) {
struct realtek_rx_buffer *rxbuf = &rtl->rxbuf;
size_t len = ( RTL_RXBUF_LEN + RTL_RXBUF_PAD );
/* Do nothing unless in legacy mode */
@@ -544,9 +545,9 @@ static void realtek_destroy_buffer ( struct realtek_nic *rtl ) {
writel ( 0, rtl->regs + RTL_RBSTART );
/* Free buffer */
dma_free ( rtl->dma, rtl->rxbuf.data, len, &rtl->rxbuf.map );
rtl->rxbuf.data = NULL;
rtl->rxbuf.offset = 0;
dma_free ( rtl->dma, rxbuf->data, len, &rxbuf->map );
rxbuf->data = NULL;
rxbuf->offset = 0;
}
/**
@@ -574,7 +575,7 @@ static int realtek_create_ring ( struct realtek_nic *rtl,
memset ( ring->desc, 0, ring->len );
/* Program ring address */
address = ring->map.addr;
address = dma ( &ring->map, ring->desc );
writel ( ( ( ( uint64_t ) address ) >> 32 ),
rtl->regs + ring->reg + 4 );
writel ( ( address & 0xffffffffUL ), rtl->regs + ring->reg );
@@ -648,7 +649,7 @@ static void realtek_refill_rx ( struct realtek_nic *rtl ) {
rtl->rx.ring.prod++;
/* Populate receive descriptor */
rx->address = cpu_to_le64 ( map->addr );
rx->address = cpu_to_le64 ( dma ( map, iobuf->data ) );
rx->length = cpu_to_le16 ( RTL_RX_MAX_LEN );
wmb();
rx->flags = ( cpu_to_le16 ( RTL_DESC_OWN ) |
@@ -797,7 +798,7 @@ static int realtek_transmit ( struct net_device *netdev,
/* Map I/O buffer */
if ( ( rc = dma_map_tx_iob ( rtl->dma, iobuf, map ) ) != 0 )
return rc;
address = map->addr;
address = dma ( map, iobuf->data );
/* Update producer index */
rtl->tx.ring.prod++;