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net: ti: icssg-prueth: Use page_pool API for RX buffer allocation
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This is to prepare for native XDP support.

The page pool API is more faster in allocating pages than
__alloc_skb(). Drawback is that it works at PAGE_SIZE granularity
so we are not efficient in memory usage.
i.e. we are using PAGE_SIZE (4KB) memory for 1.5KB max packet size.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
Link: https://patch.msgid.link/20250305101422.1908370-2-m-malladi@ti.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Roger Quadros authored and Paolo Abeni committed Mar 11, 2025
1 parent 40587f7 commit 46eeb90
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Showing 4 changed files with 150 additions and 90 deletions.
1 change: 1 addition & 0 deletions drivers/net/ethernet/ti/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -205,6 +205,7 @@ config TI_ICSSG_PRUETH_SR1
select PHYLIB
select TI_ICSS_IEP
select TI_K3_CPPI_DESC_POOL
select PAGE_POOL
depends on PRU_REMOTEPROC
depends on NET_SWITCHDEV
depends on ARCH_K3 && OF && TI_K3_UDMA_GLUE_LAYER
Expand Down
174 changes: 114 additions & 60 deletions drivers/net/ethernet/ti/icssg/icssg_common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,11 @@ void prueth_cleanup_rx_chns(struct prueth_emac *emac,
struct prueth_rx_chn *rx_chn,
int max_rflows)
{
if (rx_chn->pg_pool) {
page_pool_destroy(rx_chn->pg_pool);
rx_chn->pg_pool = NULL;
}

if (rx_chn->desc_pool)
k3_cppi_desc_pool_destroy(rx_chn->desc_pool);

Expand Down Expand Up @@ -461,43 +466,36 @@ int prueth_init_rx_chns(struct prueth_emac *emac,
}
EXPORT_SYMBOL_GPL(prueth_init_rx_chns);

int prueth_dma_rx_push(struct prueth_emac *emac,
struct sk_buff *skb,
struct prueth_rx_chn *rx_chn)
int prueth_dma_rx_push_mapped(struct prueth_emac *emac,
struct prueth_rx_chn *rx_chn,
struct page *page, u32 buf_len)
{
struct net_device *ndev = emac->ndev;
struct cppi5_host_desc_t *desc_rx;
u32 pkt_len = skb_tailroom(skb);
dma_addr_t desc_dma;
dma_addr_t buf_dma;
void **swdata;

buf_dma = page_pool_get_dma_addr(page) + PRUETH_HEADROOM;
desc_rx = k3_cppi_desc_pool_alloc(rx_chn->desc_pool);
if (!desc_rx) {
netdev_err(ndev, "rx push: failed to allocate descriptor\n");
return -ENOMEM;
}
desc_dma = k3_cppi_desc_pool_virt2dma(rx_chn->desc_pool, desc_rx);

buf_dma = dma_map_single(rx_chn->dma_dev, skb->data, pkt_len, DMA_FROM_DEVICE);
if (unlikely(dma_mapping_error(rx_chn->dma_dev, buf_dma))) {
k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);
netdev_err(ndev, "rx push: failed to map rx pkt buffer\n");
return -EINVAL;
}

cppi5_hdesc_init(desc_rx, CPPI5_INFO0_HDESC_EPIB_PRESENT,
PRUETH_NAV_PS_DATA_SIZE);
k3_udma_glue_rx_dma_to_cppi5_addr(rx_chn->rx_chn, &buf_dma);
cppi5_hdesc_attach_buf(desc_rx, buf_dma, skb_tailroom(skb), buf_dma, skb_tailroom(skb));
cppi5_hdesc_attach_buf(desc_rx, buf_dma, buf_len, buf_dma, buf_len);

swdata = cppi5_hdesc_get_swdata(desc_rx);
*swdata = skb;
*swdata = page;

return k3_udma_glue_push_rx_chn(rx_chn->rx_chn, 0,
return k3_udma_glue_push_rx_chn(rx_chn->rx_chn, PRUETH_RX_FLOW_DATA,
desc_rx, desc_dma);
}
EXPORT_SYMBOL_GPL(prueth_dma_rx_push);
EXPORT_SYMBOL_GPL(prueth_dma_rx_push_mapped);

u64 icssg_ts_to_ns(u32 hi_sw, u32 hi, u32 lo, u32 cycle_time_ns)
{
Expand Down Expand Up @@ -541,12 +539,16 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id)
u32 buf_dma_len, pkt_len, port_id = 0;
struct net_device *ndev = emac->ndev;
struct cppi5_host_desc_t *desc_rx;
struct sk_buff *skb, *new_skb;
dma_addr_t desc_dma, buf_dma;
struct page *page, *new_page;
struct page_pool *pool;
struct sk_buff *skb;
void **swdata;
u32 *psdata;
void *pa;
int ret;

pool = rx_chn->pg_pool;
ret = k3_udma_glue_pop_rx_chn(rx_chn->rx_chn, flow_id, &desc_dma);
if (ret) {
if (ret != -ENODATA)
Expand All @@ -558,48 +560,61 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id)
return 0;

desc_rx = k3_cppi_desc_pool_dma2virt(rx_chn->desc_pool, desc_dma);

swdata = cppi5_hdesc_get_swdata(desc_rx);
skb = *swdata;

psdata = cppi5_hdesc_get_psdata(desc_rx);
/* RX HW timestamp */
if (emac->rx_ts_enabled)
emac_rx_timestamp(emac, skb, psdata);

page = *swdata;
page_pool_dma_sync_for_cpu(pool, page, 0, PAGE_SIZE);
cppi5_hdesc_get_obuf(desc_rx, &buf_dma, &buf_dma_len);
k3_udma_glue_rx_cppi5_to_dma_addr(rx_chn->rx_chn, &buf_dma);
pkt_len = cppi5_hdesc_get_pktlen(desc_rx);
/* firmware adds 4 CRC bytes, strip them */
pkt_len -= 4;
cppi5_desc_get_tags_ids(&desc_rx->hdr, &port_id, NULL);

dma_unmap_single(rx_chn->dma_dev, buf_dma, buf_dma_len, DMA_FROM_DEVICE);
k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);

skb->dev = ndev;
new_skb = netdev_alloc_skb_ip_align(ndev, PRUETH_MAX_PKT_SIZE);
/* if allocation fails we drop the packet but push the
* descriptor back to the ring with old skb to prevent a stall
* descriptor back to the ring with old page to prevent a stall
*/
if (!new_skb) {
new_page = page_pool_dev_alloc_pages(pool);
if (unlikely(!new_page)) {
new_page = page;
ndev->stats.rx_dropped++;
new_skb = skb;
} else {
/* send the filled skb up the n/w stack */
skb_put(skb, pkt_len);
if (emac->prueth->is_switch_mode)
skb->offload_fwd_mark = emac->offload_fwd_mark;
skb->protocol = eth_type_trans(skb, ndev);
napi_gro_receive(&emac->napi_rx, skb);
ndev->stats.rx_bytes += pkt_len;
ndev->stats.rx_packets++;
goto requeue;
}

/* prepare skb and send to n/w stack */
pa = page_address(page);
skb = napi_build_skb(pa, PAGE_SIZE);
if (!skb) {
ndev->stats.rx_dropped++;
page_pool_recycle_direct(pool, page);
goto requeue;
}

skb_reserve(skb, PRUETH_HEADROOM);
skb_put(skb, pkt_len);
skb->dev = ndev;

psdata = cppi5_hdesc_get_psdata(desc_rx);
/* RX HW timestamp */
if (emac->rx_ts_enabled)
emac_rx_timestamp(emac, skb, psdata);

if (emac->prueth->is_switch_mode)
skb->offload_fwd_mark = emac->offload_fwd_mark;
skb->protocol = eth_type_trans(skb, ndev);

skb_mark_for_recycle(skb);
napi_gro_receive(&emac->napi_rx, skb);
ndev->stats.rx_bytes += pkt_len;
ndev->stats.rx_packets++;

requeue:
/* queue another RX DMA */
ret = prueth_dma_rx_push(emac, new_skb, &emac->rx_chns);
ret = prueth_dma_rx_push_mapped(emac, &emac->rx_chns, new_page,
PRUETH_MAX_PKT_SIZE);
if (WARN_ON(ret < 0)) {
dev_kfree_skb_any(new_skb);
page_pool_recycle_direct(pool, new_page);
ndev->stats.rx_errors++;
ndev->stats.rx_dropped++;
}
Expand All @@ -611,22 +626,16 @@ static void prueth_rx_cleanup(void *data, dma_addr_t desc_dma)
{
struct prueth_rx_chn *rx_chn = data;
struct cppi5_host_desc_t *desc_rx;
struct sk_buff *skb;
dma_addr_t buf_dma;
u32 buf_dma_len;
struct page_pool *pool;
struct page *page;
void **swdata;

pool = rx_chn->pg_pool;
desc_rx = k3_cppi_desc_pool_dma2virt(rx_chn->desc_pool, desc_dma);
swdata = cppi5_hdesc_get_swdata(desc_rx);
skb = *swdata;
cppi5_hdesc_get_obuf(desc_rx, &buf_dma, &buf_dma_len);
k3_udma_glue_rx_cppi5_to_dma_addr(rx_chn->rx_chn, &buf_dma);

dma_unmap_single(rx_chn->dma_dev, buf_dma, buf_dma_len,
DMA_FROM_DEVICE);
page = *swdata;
page_pool_recycle_direct(pool, page);
k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);

dev_kfree_skb_any(skb);
}

static int prueth_tx_ts_cookie_get(struct prueth_emac *emac)
Expand Down Expand Up @@ -907,29 +916,71 @@ int icssg_napi_rx_poll(struct napi_struct *napi_rx, int budget)
}
EXPORT_SYMBOL_GPL(icssg_napi_rx_poll);

static struct page_pool *prueth_create_page_pool(struct prueth_emac *emac,
struct device *dma_dev,
int size)
{
struct page_pool_params pp_params = { 0 };
struct page_pool *pool;

pp_params.order = 0;
pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
pp_params.pool_size = size;
pp_params.nid = dev_to_node(emac->prueth->dev);
pp_params.dma_dir = DMA_BIDIRECTIONAL;
pp_params.dev = dma_dev;
pp_params.napi = &emac->napi_rx;
pp_params.max_len = PAGE_SIZE;

pool = page_pool_create(&pp_params);
if (IS_ERR(pool))
netdev_err(emac->ndev, "cannot create rx page pool\n");

return pool;
}

int prueth_prepare_rx_chan(struct prueth_emac *emac,
struct prueth_rx_chn *chn,
int buf_size)
{
struct sk_buff *skb;
struct page_pool *pool;
struct page *page;
int i, ret;

pool = prueth_create_page_pool(emac, chn->dma_dev, chn->descs_num);
if (IS_ERR(pool))
return PTR_ERR(pool);

chn->pg_pool = pool;

for (i = 0; i < chn->descs_num; i++) {
skb = __netdev_alloc_skb_ip_align(NULL, buf_size, GFP_KERNEL);
if (!skb)
return -ENOMEM;
/* NOTE: we're not using memory efficiently here.
* 1 full page (4KB?) used here instead of
* PRUETH_MAX_PKT_SIZE (~1.5KB?)
*/
page = page_pool_dev_alloc_pages(pool);
if (!page) {
netdev_err(emac->ndev, "couldn't allocate rx page\n");
ret = -ENOMEM;
goto recycle_alloc_pg;
}

ret = prueth_dma_rx_push(emac, skb, chn);
ret = prueth_dma_rx_push_mapped(emac, chn, page, buf_size);
if (ret < 0) {
netdev_err(emac->ndev,
"cannot submit skb for rx chan %s ret %d\n",
"cannot submit page for rx chan %s ret %d\n",
chn->name, ret);
kfree_skb(skb);
return ret;
page_pool_recycle_direct(pool, page);
goto recycle_alloc_pg;
}
}

return 0;

recycle_alloc_pg:
prueth_reset_rx_chan(&emac->rx_chns, PRUETH_MAX_RX_FLOWS, false);

return ret;
}
EXPORT_SYMBOL_GPL(prueth_prepare_rx_chan);

Expand Down Expand Up @@ -958,6 +1009,9 @@ void prueth_reset_rx_chan(struct prueth_rx_chn *chn,
prueth_rx_cleanup, !!i);
if (disable)
k3_udma_glue_disable_rx_chn(chn->rx_chn);

page_pool_destroy(chn->pg_pool);
chn->pg_pool = NULL;
}
EXPORT_SYMBOL_GPL(prueth_reset_rx_chan);

Expand Down
14 changes: 11 additions & 3 deletions drivers/net/ethernet/ti/icssg/icssg_prueth.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,8 @@
#include <linux/dma/k3-udma-glue.h>

#include <net/devlink.h>
#include <net/xdp.h>
#include <net/page_pool/helpers.h>

#include "icssg_config.h"
#include "icss_iep.h"
Expand Down Expand Up @@ -131,6 +133,7 @@ struct prueth_rx_chn {
u32 descs_num;
unsigned int irq[ICSSG_MAX_RFLOWS]; /* separate irq per flow */
char name[32];
struct page_pool *pg_pool;
};

/* There are 4 Tx DMA channels, but the highest priority is CH3 (thread 3)
Expand Down Expand Up @@ -210,6 +213,10 @@ struct prueth_emac {
struct netdev_hw_addr_list vlan_mcast_list[MAX_VLAN_ID];
};

/* The buf includes headroom compatible with both skb and xdpf */
#define PRUETH_HEADROOM_NA (max(XDP_PACKET_HEADROOM, NET_SKB_PAD) + NET_IP_ALIGN)
#define PRUETH_HEADROOM ALIGN(PRUETH_HEADROOM_NA, sizeof(long))

/**
* struct prueth_pdata - PRUeth platform data
* @fdqring_mode: Free desc queue mode
Expand Down Expand Up @@ -410,9 +417,10 @@ int prueth_init_rx_chns(struct prueth_emac *emac,
struct prueth_rx_chn *rx_chn,
char *name, u32 max_rflows,
u32 max_desc_num);
int prueth_dma_rx_push(struct prueth_emac *emac,
struct sk_buff *skb,
struct prueth_rx_chn *rx_chn);
int prueth_dma_rx_push_mapped(struct prueth_emac *emac,
struct prueth_rx_chn *rx_chn,
struct page *page, u32 buf_len);
unsigned int prueth_rxbuf_total_len(unsigned int len);
void emac_rx_timestamp(struct prueth_emac *emac,
struct sk_buff *skb, u32 *psdata);
enum netdev_tx icssg_ndo_start_xmit(struct sk_buff *skb, struct net_device *ndev);
Expand Down
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