From patchwork Thu Dec 23 01:14:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Mosberger-Tang X-Patchwork-Id: 12697835 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67A8AC433F5 for ; Thu, 23 Dec 2021 01:15:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346618AbhLWBPl (ORCPT ); Wed, 22 Dec 2021 20:15:41 -0500 Received: from o1.ptr2625.egauge.net ([167.89.112.53]:27505 "EHLO o1.ptr2625.egauge.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346273AbhLWBOy (ORCPT ); Wed, 22 Dec 2021 20:14:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=egauge.net; h=from:subject:in-reply-to:references:mime-version:to:cc: content-transfer-encoding:content-type; s=sgd; bh=svs2sMYtjbzn9WErfCKbNYr+L40h6C9hhF2fxm1TnUc=; b=x5CHkg+U/AEUeKShQraCsCFovxrHQLqVVY/1oVhOKnNHL4TqqZwG/RAWfahTKh7Nj2ET 80zTsD30QLICLXvuzyBP+gAIHfKQoM/88ORaUjOBji9u5S5KxmxDDISb6qrfDlGBYXutJ1 a1rteALps9iD7gSXjz5pk7IRzDz+o9ejNZBBBgstyPvZmIY6nX3+PROOoPxiMwZTjgLjDL AFg7sz5eQhWi06Qekx3CrCJJmclFYsB0c+zJ0ga+WVUX4VWXinod9JHurcLiMh8yLDi/ql O7llWzrRjRjziC0CMbS2uiXAV1Utbt8nwS/3ufKEOzFZwB0uvn6iavnqOWyDH0Iw== Received: by filterdrecv-7bf5c69d5-w55fp with SMTP id filterdrecv-7bf5c69d5-w55fp-1-61C3CD5F-3 2021-12-23 01:14:07.106510197 +0000 UTC m=+9687232.265531122 Received: from pearl.egauge.net (unknown) by geopod-ismtpd-2-0 (SG) with ESMTP id exmKzqKWQoOJwtrusg6-sw Thu, 23 Dec 2021 01:14:06.969 +0000 (UTC) Received: by pearl.egauge.net (Postfix, from userid 1000) id 16A1B70156B; Wed, 22 Dec 2021 18:14:06 -0700 (MST) From: David Mosberger-Tang Subject: [PATCH v2 49/50] wilc1000: implement zero-copy transmit support for SPI Date: Thu, 23 Dec 2021 01:14:07 +0000 (UTC) Message-Id: <20211223011358.4031459-50-davidm@egauge.net> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211223011358.4031459-1-davidm@egauge.net> References: <20211223011358.4031459-1-davidm@egauge.net> MIME-Version: 1.0 X-SG-EID: +kMxBqj35EdRUKoy8diX1j4AXmPtd302oan+iXZuF8m2Nw4HRW2irNspffT/khET6RJF6+Prbl0h/EtF1rRLvIXjviVKntPmow2PsUz0li20mrVt8rN+SLyzZEQOCNzWH1oSVsNrpOx1b+zybfU/kDGwNSPAcuq2hGsZfhMBjwSt6MI2EM+mSNbzlKY3z3Y6L2RPeHRdgOFsskVAf2oKQAMlAjkUu2wsWOHTHPfZ9sMcxfhQ63lkxe1MDH0utZB+HgMISG453ChzSYdeH2710g== To: Ajay Singh Cc: Claudiu Beznea , Kalle Valo , "David S. Miller" , Jakub Kicinski , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Mosberger-Tang X-Entity-ID: Xg4JGAcGrJFIz2kDG9eoaQ== Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org This enables zero-copy transmits for the SPI driver. Maybe something similar could be implemented for the SDIO driver, but I'm not really familiar with it. Signed-off-by: David Mosberger-Tang --- drivers/net/wireless/microchip/wilc1000/spi.c | 162 ++++++++++++++++++ 1 file changed, 162 insertions(+) diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c index 8951202ed76e2..8d94f111ffc49 100644 --- a/drivers/net/wireless/microchip/wilc1000/spi.c +++ b/drivers/net/wireless/microchip/wilc1000/spi.c @@ -44,6 +44,8 @@ MODULE_PARM_DESC(enable_crc16, static const struct wilc_hif_func wilc_hif_spi; static int wilc_spi_reset(struct wilc *wilc); +static int wilc_spi_write_sk_buffs(struct wilc *wilc, u32 addr, + size_t num_skbs, struct sk_buff_head *skbs); /******************************************** * @@ -107,9 +109,33 @@ static int wilc_spi_reset(struct wilc *wilc); #define DATA_PKT_LOG_SZ DATA_PKT_LOG_SZ_MAX #define DATA_PKT_SZ (1 << DATA_PKT_LOG_SZ) +#define DATA_START_TAG 0xf0 +#define DATA_ORDER_FIRST 0x01 +#define DATA_ORDER_INNER 0x02 +#define DATA_ORDER_LAST 0x03 + #define WILC_SPI_COMMAND_STAT_SUCCESS 0 #define WILC_GET_RESP_HDR_START(h) (((h) >> 4) & 0xf) +/* wilc_spi_write_sk_buffs() needs the following max. number of SPI + * transfers: + * + * - 1 transfer to send the CMD_DMA_EXT_WRITE command + * - 1 transfer per sk_buff (at most WILC_VMM_TBL_SIZE of them) + * - for each data packet: + * + 1 transfer for the data start tag + * + 1 transfer for the current sk_buff (if it spans + * the boundary of a data packet) + * + 1 transfer for the optional CRC16 + * - 1 transfer to read the DMA response bytes + */ +#define MAX_DATA_PKTS DIV_ROUND_UP(WILC_TX_BUFF_SIZE, DATA_PKT_SZ) +#define MAX_SPI_XFERS \ + (1 \ + + WILC_VMM_TBL_SIZE \ + + 3 * MAX_DATA_PKTS \ + + 1) + struct wilc_spi { bool isinit; /* true if SPI protocol has been configured */ bool probing_crc; /* true if we're probing chip's CRC config */ @@ -119,6 +145,11 @@ struct wilc_spi { struct gpio_desc *enable; /* ENABLE GPIO or NULL */ struct gpio_desc *reset; /* RESET GPIO or NULL */ } gpios; + /* Scratch space used by wilc_spi_write_sk_buffs() for SPI + * transfers and the data packets' CRCs. + */ + struct spi_transfer xfer[MAX_SPI_XFERS]; + u8 crc[2 * MAX_DATA_PKTS]; }; struct wilc_spi_cmd { @@ -1037,6 +1068,136 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size) return spi_data_rsp(wilc, CMD_DMA_EXT_WRITE); } +static void wilc_spi_add_xfer(struct spi_message *msg, + struct spi_transfer **xferp, + size_t len, const void *tx_buf, void *rx_buf) +{ + struct spi_transfer *xfer = *xferp; + + xfer->tx_buf = tx_buf; + xfer->rx_buf = rx_buf; + xfer->len = len; + spi_message_add_tail(xfer, msg); + *xferp = xfer + 1; +} + +/** + * wilc_spi_write_sk_buffs() - Zero-copy write sk_buffs to the chip. + * @wilc: Pointer to the wilc structure. + * @addr: The WILC address to transfer the data to. + * @num_skbs: The length of the skbs array. + * @skbs: The queue containing the sk_buffs to transmit. + * + * Zero-copy transfer one or more sk_buffs to the WILC chip. At most + * WILC_VMM_TBL_SIZE sk_buffs may be transmitted and the total size of + * the data in the sk_buffs must not exceed WILC_VMM_TBL_SIZE. + * + * Context: The caller must hold ownership of the SPI bus through a + * call to acquire_bus(). + * + * Return: Zero on success, negative number on error. + */ +static int wilc_spi_write_sk_buffs(struct wilc *wilc, u32 addr, size_t num_skbs, + struct sk_buff_head *skbs) +{ + static const u8 data_hdr_first = DATA_START_TAG | DATA_ORDER_FIRST; + static const u8 data_hdr_inner = DATA_START_TAG | DATA_ORDER_INNER; + static const u8 data_hdr_last = DATA_START_TAG | DATA_ORDER_LAST; + size_t num_data_packets = 0, total_bytes = 0, num_sent, n, space; + struct spi_device *spi = to_spi_device(wilc->dev); + struct wilc_spi *spi_priv = wilc->bus_data; + u8 rsp[WILC_SPI_DATA_RSP_BYTES], *crc; + int i, ret, cmd_len; + struct spi_transfer *xfer; + struct wilc_spi_cmd cmd; + struct spi_message msg; + struct sk_buff *skb; + const u8 *data_hdr; + u16 crc_calc; + + /* setup the SPI message and transfers: */ + + spi_message_init(&msg); + msg.spi = spi; + + skb = skb_peek(skbs); + for (i = 0; i < num_skbs; ++i) { + n = skb->len; + total_bytes += n; + skb = skb_peek_next(skb, skbs); + } + + num_data_packets = DIV_ROUND_UP(total_bytes, DATA_PKT_SZ); + skb = skb_peek(skbs); + num_sent = 0; + xfer = spi_priv->xfer; + crc = spi_priv->crc; + + cmd_len = wilc_spi_dma_init_cmd(wilc, &cmd, CMD_DMA_EXT_WRITE, + addr, total_bytes); + if (cmd_len < 0) { + dev_err(&spi->dev, "Failed to init DMA command."); + return -EINVAL; + } + wilc_spi_add_xfer(&msg, &xfer, cmd_len, &cmd, NULL); + + for (i = 0; i < num_data_packets; ++i) { + space = DATA_PKT_SZ; + crc_calc = 0xffff; + + /* write data packet's start header: */ + if (i == num_data_packets - 1) + data_hdr = &data_hdr_last; + else if (i == 0) + data_hdr = &data_hdr_first; + else + data_hdr = &data_hdr_inner; + wilc_spi_add_xfer(&msg, &xfer, 1, data_hdr, NULL); + + /* write packet data: */ + do { + n = skb->len - num_sent; + if (n > space) + n = space; + wilc_spi_add_xfer(&msg, &xfer, n, + skb->data + num_sent, NULL); + if (spi_priv->crc16_enabled) + crc_calc = crc_itu_t(crc_calc, + skb->data + num_sent, n); + num_sent += n; + space -= n; + + if (num_sent >= skb->len) { + skb = skb_peek_next(skb, skbs); + --num_skbs; + num_sent = 0; + } + } while (space > 0 && num_skbs > 0); + + /* write optional CRC16 checksum: */ + if (spi_priv->crc16_enabled) { + crc[0] = crc_calc >> 8; + crc[1] = crc_calc; + wilc_spi_add_xfer(&msg, &xfer, 2, crc, NULL); + crc += 2; + } + } + /* last transfer reads the response bytes: */ + wilc_spi_add_xfer(&msg, &xfer, sizeof(rsp), NULL, rsp); + + WARN_ON((u8 *)xfer - (u8 *)spi_priv->xfer > sizeof(spi_priv->xfer)); + WARN_ON(crc - spi_priv->crc > sizeof(spi_priv->crc)); + + ret = spi_sync(spi, &msg); + if (ret < 0) { + dev_err(&spi->dev, "spi_sync() failed: ret=%d\n", ret); + return -EINVAL; + } + + /* Check if the chip received the data correctly: */ + return spi_data_check_rsp(wilc, rsp); +} + /******************************************** * * Bus interfaces @@ -1275,6 +1436,7 @@ static const struct wilc_hif_func wilc_hif_spi = { .hif_read_size = wilc_spi_read_size, .hif_block_tx_ext = wilc_spi_write, .hif_block_rx_ext = wilc_spi_read, + .hif_sk_buffs_tx = wilc_spi_write_sk_buffs, .hif_sync_ext = wilc_spi_sync_ext, .hif_reset = wilc_spi_reset, };