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net: ethernet: mtk_eth_soc: support 36-bit DMA addressing on MT7988
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Systems having 4 GiB of RAM and more require DMA addressing beyond the
current 32-bit limit. Starting from MT7988 the hardware now supports
36-bit DMA addressing, let's use that new capability in the driver to
avoid running into swiotlb on systems with 4 GiB of RAM or more.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/95b919c98876c9e49761e44662e7c937479eecb8.1692721443.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Daniel Golle authored and Jakub Kicinski committed Aug 24, 2023
1 parent ebb1e4f commit 2d75891
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Showing 2 changed files with 48 additions and 4 deletions.
30 changes: 28 additions & 2 deletions drivers/net/ethernet/mediatek/mtk_eth_soc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1328,6 +1328,10 @@ static void mtk_tx_set_dma_desc_v2(struct net_device *dev, void *txd,
data = TX_DMA_PLEN0(info->size);
if (info->last)
data |= TX_DMA_LS0;

if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
data |= TX_DMA_PREP_ADDR64(info->addr);

WRITE_ONCE(desc->txd3, data);

/* set forward port */
Expand Down Expand Up @@ -1997,6 +2001,7 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
bool xdp_flush = false;
int idx;
struct sk_buff *skb;
u64 addr64 = 0;
u8 *data, *new_data;
struct mtk_rx_dma_v2 *rxd, trxd;
int done = 0, bytes = 0;
Expand Down Expand Up @@ -2112,7 +2117,10 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
goto release_desc;
}

dma_unmap_single(eth->dma_dev, trxd.rxd1,
if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
addr64 = RX_DMA_GET_ADDR64(trxd.rxd2);

dma_unmap_single(eth->dma_dev, ((u64)trxd.rxd1 | addr64),
ring->buf_size, DMA_FROM_DEVICE);

skb = build_skb(data, ring->frag_size);
Expand Down Expand Up @@ -2178,6 +2186,9 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
else
rxd->rxd2 = RX_DMA_PREP_PLEN0(ring->buf_size);

if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
rxd->rxd2 |= RX_DMA_PREP_ADDR64(dma_addr);

ring->calc_idx = idx;
done++;
}
Expand Down Expand Up @@ -2670,6 +2681,9 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
else
rxd->rxd2 = RX_DMA_PREP_PLEN0(ring->buf_size);

if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
rxd->rxd2 |= RX_DMA_PREP_ADDR64(dma_addr);

rxd->rxd3 = 0;
rxd->rxd4 = 0;
if (mtk_is_netsys_v2_or_greater(eth)) {
Expand Down Expand Up @@ -2716,6 +2730,7 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)

static void mtk_rx_clean(struct mtk_eth *eth, struct mtk_rx_ring *ring, bool in_sram)
{
u64 addr64 = 0;
int i;

if (ring->data && ring->dma) {
Expand All @@ -2729,7 +2744,10 @@ static void mtk_rx_clean(struct mtk_eth *eth, struct mtk_rx_ring *ring, bool in_
if (!rxd->rxd1)
continue;

dma_unmap_single(eth->dma_dev, rxd->rxd1,
if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
addr64 = RX_DMA_GET_ADDR64(rxd->rxd2);

dma_unmap_single(eth->dma_dev, ((u64)rxd->rxd1 | addr64),
ring->buf_size, DMA_FROM_DEVICE);
mtk_rx_put_buff(ring, ring->data[i], false);
}
Expand Down Expand Up @@ -4734,6 +4752,14 @@ static int mtk_probe(struct platform_device *pdev)
}
}

if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA)) {
err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(36));
if (err) {
dev_err(&pdev->dev, "Wrong DMA config\n");
return -EINVAL;
}
}

spin_lock_init(&eth->page_lock);
spin_lock_init(&eth->tx_irq_lock);
spin_lock_init(&eth->rx_irq_lock);
Expand Down
22 changes: 20 additions & 2 deletions drivers/net/ethernet/mediatek/mtk_eth_soc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -331,6 +331,14 @@
#define TX_DMA_PLEN1(x) ((x) & eth->soc->txrx.dma_max_len)
#define TX_DMA_SWC BIT(14)
#define TX_DMA_PQID GENMASK(3, 0)
#define TX_DMA_ADDR64_MASK GENMASK(3, 0)
#if IS_ENABLED(CONFIG_64BIT)
# define TX_DMA_GET_ADDR64(x) (((u64)FIELD_GET(TX_DMA_ADDR64_MASK, (x))) << 32)
# define TX_DMA_PREP_ADDR64(x) FIELD_PREP(TX_DMA_ADDR64_MASK, ((x) >> 32))
#else
# define TX_DMA_GET_ADDR64(x) (0)
# define TX_DMA_PREP_ADDR64(x) (0)
#endif

/* PDMA on MT7628 */
#define TX_DMA_DONE BIT(31)
Expand All @@ -343,6 +351,14 @@
#define RX_DMA_PREP_PLEN0(x) (((x) & eth->soc->txrx.dma_max_len) << eth->soc->txrx.dma_len_offset)
#define RX_DMA_GET_PLEN0(x) (((x) >> eth->soc->txrx.dma_len_offset) & eth->soc->txrx.dma_max_len)
#define RX_DMA_VTAG BIT(15)
#define RX_DMA_ADDR64_MASK GENMASK(3, 0)
#if IS_ENABLED(CONFIG_64BIT)
# define RX_DMA_GET_ADDR64(x) (((u64)FIELD_GET(RX_DMA_ADDR64_MASK, (x))) << 32)
# define RX_DMA_PREP_ADDR64(x) FIELD_PREP(RX_DMA_ADDR64_MASK, ((x) >> 32))
#else
# define RX_DMA_GET_ADDR64(x) (0)
# define RX_DMA_PREP_ADDR64(x) (0)
#endif

/* QDMA descriptor rxd3 */
#define RX_DMA_VID(x) ((x) & VLAN_VID_MASK)
Expand Down Expand Up @@ -942,6 +958,7 @@ enum mkt_eth_capabilities {
MTK_RSTCTRL_PPE2_BIT,
MTK_U3_COPHY_V2_BIT,
MTK_SRAM_BIT,
MTK_36BIT_DMA_BIT,

/* MUX BITS*/
MTK_ETH_MUX_GDM1_TO_GMAC1_ESW_BIT,
Expand Down Expand Up @@ -978,6 +995,7 @@ enum mkt_eth_capabilities {
#define MTK_RSTCTRL_PPE2 BIT_ULL(MTK_RSTCTRL_PPE2_BIT)
#define MTK_U3_COPHY_V2 BIT_ULL(MTK_U3_COPHY_V2_BIT)
#define MTK_SRAM BIT_ULL(MTK_SRAM_BIT)
#define MTK_36BIT_DMA BIT_ULL(MTK_36BIT_DMA_BIT)

#define MTK_ETH_MUX_GDM1_TO_GMAC1_ESW \
BIT_ULL(MTK_ETH_MUX_GDM1_TO_GMAC1_ESW_BIT)
Expand Down Expand Up @@ -1059,8 +1077,8 @@ enum mkt_eth_capabilities {
MTK_MUX_GMAC12_TO_GEPHY_SGMII | MTK_QDMA | \
MTK_RSTCTRL_PPE1 | MTK_SRAM)

#define MT7988_CAPS (MTK_GDM1_ESW | MTK_QDMA | MTK_RSTCTRL_PPE1 | \
MTK_RSTCTRL_PPE2 | MTK_SRAM)
#define MT7988_CAPS (MTK_36BIT_DMA | MTK_GDM1_ESW | MTK_QDMA | \
MTK_RSTCTRL_PPE1 | MTK_RSTCTRL_PPE2 | MTK_SRAM)

struct mtk_tx_dma_desc_info {
dma_addr_t addr;
Expand Down

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