Re: [PATCH net-next v5 4/4] net: ocelot: add FDMA support
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-12-07 13:52:08
Also in:
lkml, netdev
On Tue, Dec 07, 2021 at 10:08:53AM +0100, Clément Léger wrote:
Ethernet frames can be extracted or injected autonomously to or from the device’s DDR3/DDR3L memory and/or PCIe memory space. Linked list data structures in memory are used for injecting or extracting Ethernet frames. The FDMA generates interrupts when frame extraction or injection is done and when the linked lists need updating. The FDMA is shared between all the ethernet ports of the switch and uses a linked list of descriptors (DCB) to inject and extract packets. Before adding descriptors, the FDMA channels must be stopped. It would be inefficient to do that each time a descriptor would be added so the channels are restarted only once they stopped. Both channels uses ring-like structure to feed the DCBs to the FDMA. head and tail are never touched by hardware and are completely handled by the driver. On top of that, page recycling has been added and is mostly taken from gianfar driver. Co-developed-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Clément Léger <clement.leger@bootlin.com> ---
+static void ocelot_fdma_send_skb(struct ocelot *ocelot,
+ struct ocelot_fdma *fdma, struct sk_buff *skb)
+{
+ struct ocelot_fdma_tx_ring *tx_ring = &fdma->tx_ring;
+ struct ocelot_fdma_tx_buf *tx_buf;
+ struct ocelot_fdma_dcb *dcb;
+ dma_addr_t dma;
+ u16 next_idx;
+
+ dcb = &tx_ring->dcbs[tx_ring->next_to_use];
+ tx_buf = &tx_ring->bufs[tx_ring->next_to_use];
+ if (!ocelot_fdma_tx_dcb_set_skb(ocelot, tx_buf, dcb, skb)) {
+ dev_kfree_skb_any(skb);
+ return;
+ }
+
+ next_idx = ocelot_fdma_idx_next(tx_ring->next_to_use,
+ OCELOT_FDMA_TX_RING_SIZE);
+ /* If the FDMA TX chan is empty, then enqueue the DCB directly */
+ if (ocelot_fdma_tx_ring_empty(fdma)) {
+ dma = ocelot_fdma_idx_dma(tx_ring->dcbs_dma, tx_ring->next_to_use);
+ ocelot_fdma_activate_chan(ocelot, dma, MSCC_FDMA_INJ_CHAN);
+ } else {
+ /* Chain the DCBs */
+ dcb->llp = ocelot_fdma_idx_dma(tx_ring->dcbs_dma, next_idx);
+ }
+ skb_tx_timestamp(skb);
+
+ tx_ring->next_to_use = next_idx;You've decided against moving these before ocelot_fdma_activate_chan? The skb may be freed by ocelot_fdma_tx_cleanup() before skb_tx_timestamp() has a chance to run, is this not true?
quoted hunk ↗ jump to hunk
+}diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c index cd3eb101f159..bee883a0b5b8 100644 --- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c +++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c@@ -18,6 +18,7 @@ #include <soc/mscc/ocelot_vcap.h> #include <soc/mscc/ocelot_hsio.h> +#include "ocelot_fdma.h" #include "ocelot.h" #define VSC7514_VCAP_POLICER_BASE 128@@ -275,6 +276,18 @@ static const u32 ocelot_ptp_regmap[] = { REG(PTP_CLK_CFG_ADJ_FREQ, 0x0000a8), }; +static const u32 ocelot_fdma_regmap[] = { + REG(PTP_PIN_CFG, 0x000000), + REG(PTP_PIN_TOD_SEC_MSB, 0x000004), + REG(PTP_PIN_TOD_SEC_LSB, 0x000008), + REG(PTP_PIN_TOD_NSEC, 0x00000c), + REG(PTP_PIN_WF_HIGH_PERIOD, 0x000014), + REG(PTP_PIN_WF_LOW_PERIOD, 0x000018), + REG(PTP_CFG_MISC, 0x0000a0), + REG(PTP_CLK_CFG_ADJ_CFG, 0x0000a4), + REG(PTP_CLK_CFG_ADJ_FREQ, 0x0000a8), +};
drivers/net/ethernet/mscc/ocelot_vsc7514.c:279:18: warning: ‘ocelot_fdma_regmap’ defined but not used [-Wunused-const-variable=]
279 | static const u32 ocelot_fdma_regmap[] = {
| ^~~~~~~~~~~~~~~~~~
Not to mention this isn't even the FDMA regmap.
quoted hunk ↗ jump to hunk
+ static const u32 ocelot_dev_gmii_regmap[] = { REG(DEV_CLOCK_CFG, 0x0), REG(DEV_PORT_MISC, 0x4),@@ -1048,6 +1061,7 @@ static int mscc_ocelot_probe(struct platform_device *pdev) { S1, "s1" }, { S2, "s2" }, { PTP, "ptp", 1 }, + { FDMA, "fdma", 1 }, };