[PATCH v2 02/14] net: ethernet: mtk_eth_soc: add support for coherent DMA

Felix Fietkau
2022-04-05T20:01:21Z

It improves performance by eliminating the need for a cache flush on rx and tx
In preparation for supporting WED (Wireless Ethernet Dispatch), also add a
function for disabling coherent DMA at runtime.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 95 +++++++++++++++------
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 9 ++
2 files changed, 80 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index f02d07ec5ccb..70db217ed831 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -9,6 +9,7 @@
#include <linux/of_device.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
+#include <linux/of_address.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/clk.h>
@@ -786,7 +787,7 @@ static int mtk_init_fq_dma(struct mtk_eth *eth)
dma_addr_t dma_addr;
int i;

- eth->scratch_ring = dma_alloc_coherent(eth->dev,
+ eth->scratch_ring = dma_alloc_coherent(eth->dma_dev,
cnt * sizeof(struct mtk_tx_dma),
&eth->phy_scratch_ring,
GFP_ATOMIC);
@@ -798,10 +799,10 @@ static int mtk_init_fq_dma(struct mtk_eth *eth)
if (unlikely(!eth->scratch_head))
return -ENOMEM;

- dma_addr = dma_map_single(eth->dev,
+ dma_addr = dma_map_single(eth->dma_dev,
eth->scratch_head, cnt * MTK_QDMA_PAGE_SIZE,
DMA_FROM_DEVICE);
- if (unlikely(dma_mapping_error(eth->dev, dma_addr)))
+ if (unlikely(dma_mapping_error(eth->dma_dev, dma_addr)))
return -ENOMEM;

phy_ring_tail = eth->phy_scratch_ring +
@@ -855,26 +856,26 @@ static void mtk_tx_unmap(struct mtk_eth *eth, struct mtk_tx_buf *tx_buf,
{
if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA)) {
if (tx_buf->flags & MTK_TX_FLAGS_SINGLE0) {
- dma_unmap_single(eth->dev,
+ dma_unmap_single(eth->dma_dev,
dma_unmap_addr(tx_buf, dma_addr0),
dma_unmap_len(tx_buf, dma_len0),
DMA_TO_DEVICE);
} else if (tx_buf->flags & MTK_TX_FLAGS_PAGE0) {
- dma_unmap_page(eth->dev,
+ dma_unmap_page(eth->dma_dev,
dma_unmap_addr(tx_buf, dma_addr0),
dma_unmap_len(tx_buf, dma_len0),
DMA_TO_DEVICE);
}
} else {
if (dma_unmap_len(tx_buf, dma_len0)) {
- dma_unmap_page(eth->dev,
+ dma_unmap_page(eth->dma_dev,
dma_unmap_addr(tx_buf, dma_addr0),
dma_unmap_len(tx_buf, dma_len0),
DMA_TO_DEVICE);
}

if (dma_unmap_len(tx_buf, dma_len1)) {
- dma_unmap_page(eth->dev,
+ dma_unmap_page(eth->dma_dev,
dma_unmap_addr(tx_buf, dma_addr1),
dma_unmap_len(tx_buf, dma_len1),
DMA_TO_DEVICE);
@@ -952,9 +953,9 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
if (skb_vlan_tag_present(skb))
txd4 |= TX_DMA_INS_VLAN | skb_vlan_tag_get(skb);

- mapped_addr = dma_map_single(eth->dev, skb->data,
+ mapped_addr = dma_map_single(eth->dma_dev, skb->data,
skb_headlen(skb), DMA_TO_DEVICE);
- if (unlikely(dma_mapping_error(eth->dev, mapped_addr)))
+ if (unlikely(dma_mapping_error(eth->dma_dev, mapped_addr)))
return -ENOMEM;

WRITE_ONCE(itxd->txd1, mapped_addr);
@@ -993,10 +994,10 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,

frag_map_size = min(frag_size, MTK_TX_DMA_BUF_LEN);
- mapped_addr = skb_frag_dma_map(eth->dev, frag, offset,
+ mapped_addr = skb_frag_dma_map(eth->dma_dev, frag, offset,
frag_map_size,
DMA_TO_DEVICE);
- if (unlikely(dma_mapping_error(eth->dev, mapped_addr)))
+ if (unlikely(dma_mapping_error(eth->dma_dev, mapped_addr)))
goto err_dma;

if (i == nr_frags - 1 &&
@@ -1274,18 +1275,18 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
netdev->stats.rx_dropped++;
goto release_desc;
}
- dma_addr = dma_map_single(eth->dev,
+ dma_addr = dma_map_single(eth->dma_dev,
new_data + NET_SKB_PAD +
eth->ip_align,
ring->buf_size,
DMA_FROM_DEVICE);
- if (unlikely(dma_mapping_error(eth->dev, dma_addr))) {
+ if (unlikely(dma_mapping_error(eth->dma_dev, dma_addr))) {
skb_free_frag(new_data);
netdev->stats.rx_dropped++;
goto release_desc;
}

- dma_unmap_single(eth->dev, trxd.rxd1,
+ dma_unmap_single(eth->dma_dev, trxd.rxd1,
ring->buf_size, DMA_FROM_DEVICE);

/* receive data */
@@ -1558,7 +1559,7 @@ static int mtk_tx_alloc(struct mtk_eth *eth)
if (!ring->buf)
goto no_tx_mem;

- ring->dma = dma_alloc_coherent(eth->dev, MTK_DMA_SIZE * sz,
+ ring->dma = dma_alloc_coherent(eth->dma_dev, MTK_DMA_SIZE * sz,
&ring->phys, GFP_ATOMIC);
if (!ring->dma)
goto no_tx_mem;
@@ -1576,7 +1577,7 @@ static int mtk_tx_alloc(struct mtk_eth *eth)
* descriptors in ring->dma_pdma.
*/
if (!MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA)) {
- ring->dma_pdma = dma_alloc_coherent(eth->dev, MTK_DMA_SIZE * sz,
+ ring->dma_pdma = dma_alloc_coherent(eth->dma_dev, MTK_DMA_SIZE * sz,
&ring->phys_pdma,
GFP_ATOMIC);
if (!ring->dma_pdma)
@@ -1635,7 +1636,7 @@ static void mtk_tx_clean(struct mtk_eth *eth)
}

if (ring->dma) {
- dma_free_coherent(eth->dev,
+ dma_free_coherent(eth->dma_dev,
MTK_DMA_SIZE * sizeof(*ring->dma),
ring->dma,
ring->phys);
@@ -1643,7 +1644,7 @@ static void mtk_tx_clean(struct mtk_eth *eth)
}

if (ring->dma_pdma) {
- dma_free_coherent(eth->dev,
+ dma_free_coherent(eth->dma_dev,
MTK_DMA_SIZE * sizeof(*ring->dma_pdma),
ring->dma_pdma,
ring->phys_pdma);
@@ -1688,18 +1689,18 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
return -ENOMEM;
}

- ring->dma = dma_alloc_coherent(eth->dev,
+ ring->dma = dma_alloc_coherent(eth->dma_dev,
rx_dma_size * sizeof(*ring->dma),
&ring->phys, GFP_ATOMIC);
if (!ring->dma)
return -ENOMEM;

for (i = 0; i < rx_dma_size; i++) {
- dma_addr_t dma_addr = dma_map_single(eth->dev,
+ dma_addr_t dma_addr = dma_map_single(eth->dma_dev,
ring->data[i] + NET_SKB_PAD + eth->ip_align,
ring->buf_size,
DMA_FROM_DEVICE);
- if (unlikely(dma_mapping_error(eth->dev, dma_addr)))
+ if (unlikely(dma_mapping_error(eth->dma_dev, dma_addr)))
return -ENOMEM;
ring->dma[i].rxd1 = (unsigned int)dma_addr;

@@ -1735,7 +1736,7 @@ static void mtk_rx_clean(struct mtk_eth *eth, struct mtk_rx_ring *ring)
continue;
if (!ring->dma[i].rxd1)
continue;
- dma_unmap_single(eth->dev,
+ dma_unmap_single(eth->dma_dev,
ring->dma[i].rxd1,
ring->buf_size,
DMA_FROM_DEVICE);
@@ -1746,7 +1747,7 @@ static void mtk_rx_clean(struct mtk_eth *eth, struct mtk_rx_ring *ring)
}

if (ring->dma) {
- dma_free_coherent(eth->dev,
+ dma_free_coherent(eth->dma_dev,
ring->dma_size * sizeof(*ring->dma),
ring->dma,
ring->phys);
@@ -2099,7 +2100,7 @@ static void mtk_dma_free(struct mtk_eth *eth)
if (eth->netdev[i])
netdev_reset_queue(eth->netdev[i]);
if (eth->scratch_ring) {
- dma_free_coherent(eth->dev,
+ dma_free_coherent(eth->dma_dev,
MTK_DMA_SIZE * sizeof(struct mtk_tx_dma),
eth->scratch_ring,
eth->phy_scratch_ring);
@@ -2448,6 +2449,8 @@ static void mtk_dim_tx(struct work_struct *work)

static int mtk_hw_init(struct mtk_eth *eth)
{
+ u32 dma_mask = ETHSYS_DMA_AG_MAP_PDMA | ETHSYS_DMA_AG_MAP_QDMA |
+ ETHSYS_DMA_AG_MAP_PPE;
int i, val, ret;

if (test_and_set_bit(MTK_HW_INIT, &eth->state))
@@ -2460,6 +2463,10 @@ static int mtk_hw_init(struct mtk_eth *eth)
if (ret)
goto err_disable_pm;

+ if (eth->ethsys)
+ regmap_update_bits(eth->ethsys, ETHSYS_DMA_AG_MAP, dma_mask,
+ of_dma_is_coherent(eth->dma_dev->of_node) * dma_mask);
+
if (MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628)) {
ret = device_reset(eth->dev);
if (ret) {
@@ -3040,6 +3047,35 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
return err;
}

+void mtk_eth_set_dma_device(struct mtk_eth *eth, struct device *dma_dev)
+{
+ struct net_device *dev, *tmp;
+ LIST_HEAD(dev_list);
+ int i;
+
+ rtnl_lock();
+
+ for (i = 0; i < MTK_MAC_COUNT; i++) {
+ dev = eth->netdev[i];
+
+ if (!dev || !(dev->flags & IFF_UP))
+ continue;
+
+ list_add_tail(&dev->close_list, &dev_list);
+ }
+
+ dev_close_many(&dev_list, false);
+
+ eth->dma_dev = dma_dev;
+
+ list_for_each_entry_safe(dev, tmp, &dev_list, close_list) {
+ list_del_init(&dev->close_list);
+ dev_open(dev, NULL);
+ }
+
+ rtnl_unlock();
+}
+
static int mtk_probe(struct platform_device *pdev)
{
struct device_node *mac_np;
@@ -3053,6 +3089,7 @@ static int mtk_probe(struct platform_device *pdev)
eth->soc = of_device_get_match_data(&pdev->dev);

eth->dev = &pdev->dev;
+ eth->dma_dev = &pdev->dev;
eth->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(eth->base))
return PTR_ERR(eth->base);
@@ -3101,6 +3138,16 @@ static int mtk_probe(struct platform_device *pdev)
}
}

+ if (of_dma_is_coherent(pdev->dev.of_node)) {
+ struct regmap *cci;
+
+ cci = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+ "mediatek,cci-control");
+ /* enable CPU/bus coherency */
+ if (!IS_ERR(cci))
+ regmap_write(cci, 0, 3);
+ }
+
if (MTK_HAS_CAPS(eth->soc->caps, MTK_SGMII)) {
eth->sgmii = devm_kzalloc(eth->dev, sizeof(*eth->sgmii),
GFP_KERNEL);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index c9d42be314b5..e701544c4287 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -465,6 +465,12 @@
#define RSTCTRL_FE BIT(6)
#define RSTCTRL_PPE BIT(31)

+/* ethernet dma channel agent map */
+#define ETHSYS_DMA_AG_MAP 0x408
+#define ETHSYS_DMA_AG_MAP_PDMA BIT(0)
+#define ETHSYS_DMA_AG_MAP_QDMA BIT(1)
+#define ETHSYS_DMA_AG_MAP_PPE BIT(2)
+
/* SGMII subsystem config registers */
/* Register to auto-negotiation restart */
#define SGMSYS_PCS_CONTROL_1 0x0
@@ -882,6 +888,7 @@ struct mtk_sgmii {
/* struct mtk_eth - This is the main datasructure for holding the state
* of the driver
* @dev: The device pointer
+ * @dev: The device pointer used for dma mapping/alloc
* @base: The mapped register i/o base
* @page_lock: Make sure that register operations are atomic
* @tx_irq__lock: Make sure that IRQ register operations are atomic
@@ -925,6 +932,7 @@ struct mtk_sgmii {

struct mtk_eth {
struct device *dev;
+ struct device *dma_dev;
void __iomem *base;
spinlock_t page_lock;
spinlock_t tx_irq_lock;
@@ -1023,6 +1031,7 @@ int mtk_gmac_rgmii_path_setup(struct mtk_eth *eth, int mac_id);
int mtk_eth_offload_init(struct mtk_eth *eth);
int mtk_eth_setup_tc(struct net_device *dev, enum tc_setup_type type,
void *type_data);
+void mtk_eth_set_dma_device(struct mtk_eth *eth, struct device *dma_dev);

#endif /* MTK_ETH_H */
--
2.35.1