[PATCH net-next v3 4/4] net: lan96x: Use page_pool API

From: Horatiu Vultur
Date: Wed Nov 09 2022 - 15:42:11 EST

Use the page_pool API for allocation, freeing and DMA handling instead
of dev_alloc_pages, __free_pages and dma_map_page.

Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
.../net/ethernet/microchip/lan966x/Kconfig | 1 +
.../ethernet/microchip/lan966x/lan966x_fdma.c | 89 ++++++++++---------
.../ethernet/microchip/lan966x/lan966x_main.h | 8 ++
3 files changed, 58 insertions(+), 40 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/Kconfig b/drivers/net/ethernet/microchip/lan966x/Kconfig
index 49e1464a43139..b7ae5ce7d3f7a 100644
--- a/drivers/net/ethernet/microchip/lan966x/Kconfig
+++ b/drivers/net/ethernet/microchip/lan966x/Kconfig
@@ -7,5 +7,6 @@ config LAN966X_SWITCH
depends on BRIDGE || BRIDGE=n
select PHYLINK
select PACKING
+ select PAGE_POOL
help
This driver supports the Lan966x network switch device.
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index fa4198c617667..5fbbd479cfb06 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -10,47 +10,25 @@ static int lan966x_fdma_channel_active(struct lan966x *lan966x)
static struct page *lan966x_fdma_rx_alloc_page(struct lan966x_rx *rx,
struct lan966x_db *db)
{
- struct lan966x *lan966x = rx->lan966x;
- dma_addr_t dma_addr;
struct page *page;

- page = dev_alloc_pages(rx->page_order);
+ page = page_pool_dev_alloc_pages(rx->page_pool);
if (unlikely(!page))
return NULL;

- dma_addr = dma_map_page(lan966x->dev, page, 0,
- PAGE_SIZE << rx->page_order,
- DMA_FROM_DEVICE);
- if (unlikely(dma_mapping_error(lan966x->dev, dma_addr)))
- goto free_page;
-
- db->dataptr = dma_addr;
+ db->dataptr = page_pool_get_dma_addr(page);

return page;
-
-free_page:
- __free_pages(page, rx->page_order);
- return NULL;
}

static void lan966x_fdma_rx_free_pages(struct lan966x_rx *rx)
{
- struct lan966x *lan966x = rx->lan966x;
- struct lan966x_rx_dcb *dcb;
- struct lan966x_db *db;
int i, j;

for (i = 0; i < FDMA_DCB_MAX; ++i) {
- dcb = &rx->dcbs[i];
-
- for (j = 0; j < FDMA_RX_DCB_MAX_DBS; ++j) {
- db = &dcb->db[j];
- dma_unmap_single(lan966x->dev,
- (dma_addr_t)db->dataptr,
- PAGE_SIZE << rx->page_order,
- DMA_FROM_DEVICE);
- __free_pages(rx->page[i][j], rx->page_order);
- }
+ for (j = 0; j < FDMA_RX_DCB_MAX_DBS; ++j)
+ page_pool_put_full_page(rx->page_pool,
+ rx->page[i][j], false);
}
}

@@ -62,7 +40,7 @@ static void lan966x_fdma_rx_free_page(struct lan966x_rx *rx)
if (unlikely(!page))
return;

- __free_pages(page, rx->page_order);
+ page_pool_recycle_direct(rx->page_pool, page);
}

static void lan966x_fdma_rx_add_dcb(struct lan966x_rx *rx,
@@ -84,6 +62,25 @@ static void lan966x_fdma_rx_add_dcb(struct lan966x_rx *rx,
rx->last_entry = dcb;
}

+static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
+{
+ struct lan966x *lan966x = rx->lan966x;
+ struct page_pool_params pp_params = {
+ .order = rx->page_order,
+ .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
+ .pool_size = FDMA_DCB_MAX,
+ .nid = NUMA_NO_NODE,
+ .dev = lan966x->dev,
+ .dma_dir = DMA_FROM_DEVICE,
+ .offset = 0,
+ .max_len = rx->max_mtu -
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ };
+
+ rx->page_pool = page_pool_create(&pp_params);
+ return PTR_ERR_OR_ZERO(rx->page_pool);
+}
+
static int lan966x_fdma_rx_alloc(struct lan966x_rx *rx)
{
struct lan966x *lan966x = rx->lan966x;
@@ -93,6 +90,9 @@ static int lan966x_fdma_rx_alloc(struct lan966x_rx *rx)
int i, j;
int size;

+ if (lan966x_fdma_rx_alloc_page_pool(rx))
+ return PTR_ERR(rx->page_pool);
+
/* calculate how many pages are needed to allocate the dcbs */
size = sizeof(struct lan966x_rx_dcb) * FDMA_DCB_MAX;
size = ALIGN(size, PAGE_SIZE);
@@ -436,10 +436,6 @@ static int lan966x_fdma_rx_check_frame(struct lan966x_rx *rx, u64 *src_port)
FDMA_DCB_STATUS_BLOCKL(db->status),
DMA_FROM_DEVICE);

- dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
- PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
- DMA_ATTR_SKIP_CPU_SYNC);
-
lan966x_ifh_get_src_port(page_address(page), src_port);
if (WARN_ON(*src_port >= lan966x->num_phys_ports))
return FDMA_ERROR;
@@ -468,6 +464,8 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
if (unlikely(!skb))
goto free_page;

+ skb_mark_for_recycle(skb);
+
skb_put(skb, FDMA_DCB_STATUS_BLOCKL(db->status));

lan966x_ifh_get_timestamp(skb->data, &timestamp);
@@ -495,7 +493,7 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
return skb;

free_page:
- __free_pages(page, rx->page_order);
+ page_pool_recycle_direct(rx->page_pool, page);

return NULL;
}
@@ -740,6 +738,7 @@ static int lan966x_qsys_sw_status(struct lan966x *lan966x)

static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
{
+ struct page_pool *page_pool;
dma_addr_t rx_dma;
void *rx_dcbs;
u32 size;
@@ -748,6 +747,7 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
/* Store these for later to free them */
rx_dma = lan966x->rx.dma;
rx_dcbs = lan966x->rx.dcbs;
+ page_pool = lan966x->rx.page_pool;

napi_synchronize(&lan966x->napi);
napi_disable(&lan966x->napi);
@@ -756,6 +756,7 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
lan966x_fdma_rx_disable(&lan966x->rx);
lan966x_fdma_rx_free_pages(&lan966x->rx);
lan966x->rx.page_order = round_up(new_mtu, PAGE_SIZE) / PAGE_SIZE - 1;
+ lan966x->rx.max_mtu = new_mtu;
err = lan966x_fdma_rx_alloc(&lan966x->rx);
if (err)
goto restore;
@@ -765,11 +766,14 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
size = ALIGN(size, PAGE_SIZE);
dma_free_coherent(lan966x->dev, size, rx_dcbs, rx_dma);

+ page_pool_destroy(page_pool);
+
lan966x_fdma_wakeup_netdev(lan966x);
napi_enable(&lan966x->napi);

return err;
restore:
+ lan966x->rx.page_pool = page_pool;
lan966x->rx.dma = rx_dma;
lan966x->rx.dcbs = rx_dcbs;
lan966x_fdma_rx_start(&lan966x->rx);
@@ -777,19 +781,22 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
return err;
}

+static int lan966x_fdma_get_max_frame(struct lan966x *lan966x)
+{
+ return lan966x_fdma_get_max_mtu(lan966x) +
+ IFH_LEN_BYTES +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
+ VLAN_HLEN * 2;
+}
+
int lan966x_fdma_change_mtu(struct lan966x *lan966x)
{
int max_mtu;
int err;
u32 val;

- max_mtu = lan966x_fdma_get_max_mtu(lan966x);
- max_mtu += IFH_LEN_BYTES;
- max_mtu += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- max_mtu += VLAN_HLEN * 2;
-
- if (round_up(max_mtu, PAGE_SIZE) / PAGE_SIZE - 1 ==
- lan966x->rx.page_order)
+ max_mtu = lan966x_fdma_get_max_frame(lan966x);
+ if (max_mtu == lan966x->rx.max_mtu)
return 0;

/* Disable the CPU port */
@@ -844,6 +851,7 @@ int lan966x_fdma_init(struct lan966x *lan966x)

lan966x->rx.lan966x = lan966x;
lan966x->rx.channel_id = FDMA_XTR_CHANNEL;
+ lan966x->rx.max_mtu = lan966x_fdma_get_max_frame(lan966x);
lan966x->tx.lan966x = lan966x;
lan966x->tx.channel_id = FDMA_INJ_CHANNEL;
lan966x->tx.last_in_use = -1;
@@ -876,5 +884,6 @@ void lan966x_fdma_deinit(struct lan966x *lan966x)

lan966x_fdma_rx_free_pages(&lan966x->rx);
lan966x_fdma_rx_free(&lan966x->rx);
+ page_pool_destroy(lan966x->rx.page_pool);
lan966x_fdma_tx_free(&lan966x->tx);
}
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index b3b0619b17c61..bc93051aa0798 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -9,6 +9,7 @@
#include <linux/phy.h>
#include <linux/phylink.h>
#include <linux/ptp_clock_kernel.h>
+#include <net/page_pool.h>
#include <net/pkt_cls.h>
#include <net/pkt_sched.h>
#include <net/switchdev.h>
@@ -161,7 +162,14 @@ struct lan966x_rx {
*/
u8 page_order;

+ /* Represents the max size frame that it can receive to the CPU. This
+ * includes the IFH + VLAN tags + frame + skb_shared_info
+ */
+ u32 max_mtu;
+
u8 channel_id;
+
+ struct page_pool *page_pool;
};

struct lan966x_tx_dcb_buf {
--
2.38.0