[PATCH v5 17/17] net: qualcomm: add QCA7000 UART driver

Stefan Wahren
2017-05-10T08:53:28Z

This patch adds the Ethernet over UART driver for the
Qualcomm QCA7000 HomePlug GreenPHY.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
drivers/net/ethernet/qualcomm/Kconfig | 16 +
drivers/net/ethernet/qualcomm/Makefile | 2 +
drivers/net/ethernet/qualcomm/qca_7k_common.h | 6 +
drivers/net/ethernet/qualcomm/qca_uart.c | 423 ++++++++++++++++++++++++++
4 files changed, 447 insertions(+)
create mode 100644 drivers/net/ethernet/qualcomm/qca_uart.c

diff --git a/drivers/net/ethernet/qualcomm/Kconfig b/drivers/net/ethernet/qualcomm/Kconfig
index b4c369d..877675a 100644
--- a/drivers/net/ethernet/qualcomm/Kconfig
+++ b/drivers/net/ethernet/qualcomm/Kconfig
@@ -30,6 +30,22 @@ config QCA7000_SPI
To compile this driver as a module, choose M here. The module
will be called qcaspi.

+config QCA7000_UART
+ tristate "Qualcomm Atheros QCA7000 UART support"
+ select QCA7000
+ depends on SERIAL_DEV_BUS && OF
+ ---help---
+ This UART protocol driver supports the Qualcomm Atheros QCA7000.
+
+ Currently the driver assumes these device UART settings:
+ Data bits: 8
+ Parity: None
+ Stop bits: 1
+ Flow control: None
+
+ To compile this driver as a module, choose M here. The module
+ will be called qcauart.
+
config QCOM_EMAC
tristate "Qualcomm Technologies, Inc. EMAC Gigabit Ethernet support"
depends on HAS_DMA && HAS_IOMEM
diff --git a/drivers/net/ethernet/qualcomm/Makefile b/drivers/net/ethernet/qualcomm/Makefile
index 65556ca..92fa7c4 100644
--- a/drivers/net/ethernet/qualcomm/Makefile
+++ b/drivers/net/ethernet/qualcomm/Makefile
@@ -5,5 +5,7 @@
obj-$(CONFIG_QCA7000) += qca_7k_common.o
obj-$(CONFIG_QCA7000_SPI) += qcaspi.o
qcaspi-objs := qca_7k.o qca_debug.o qca_spi.o
+obj-$(CONFIG_QCA7000_UART) += qcauart.o
+qcauart-objs := qca_uart.o

obj-y += emac/
diff --git a/drivers/net/ethernet/qualcomm/qca_7k_common.h b/drivers/net/ethernet/qualcomm/qca_7k_common.h
index 07bdd6c..928554f 100644
--- a/drivers/net/ethernet/qualcomm/qca_7k_common.h
+++ b/drivers/net/ethernet/qualcomm/qca_7k_common.h
@@ -122,6 +122,12 @@ static inline void qcafrm_fsm_init_spi(struct qcafrm_handle *handle)
handle->state = handle->init;
}

+static inline void qcafrm_fsm_init_uart(struct qcafrm_handle *handle)
+{
+ handle->init = QCAFRM_WAIT_AA1;
+ handle->state = handle->init;
+}
+
/* Gather received bytes and try to extract a full Ethernet frame
* by following a simple state machine.
*
diff --git a/drivers/net/ethernet/qualcomm/qca_uart.c b/drivers/net/ethernet/qualcomm/qca_uart.c
new file mode 100644
index 0000000..1f6514c
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/qca_uart.c
@@ -0,0 +1,423 @@
+/*
+ * Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
+ * Copyright (c) 2017, I2SE GmbH
+ *
+ * Permission to use, copy, modify, and/or distribute this software
+ * for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear
+ * in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* This module implements the Qualcomm Atheros UART protocol for
+ * kernel-based UART device; it is essentially an Ethernet-to-UART
+ * serial converter;
+ */
+
+#include <linux/errno.h>
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_net.h>
+#include <linux/sched.h>
+#include <linux/serdev.h>
+#include <linux/skbuff.h>
+#include <linux/types.h>
+
+#include "qca_7k_common.h"
+
+#define QCAUART_DRV_VERSION "0.1.0"
+#define QCAUART_DRV_NAME "qcauart"
+#define QCAUART_TX_TIMEOUT (1 * HZ)
+
+struct qcauart {
+ struct net_device *net_dev;
+ spinlock_t lock; /* transmit lock */
+ struct work_struct tx_work; /* Flushes transmit buffer */
+
+ struct serdev_device *serdev;
+ struct qcafrm_handle frm_handle;
+ struct sk_buff *rx_skb;
+
+ unsigned char *tx_head; /* pointer to next XMIT byte */
+ int tx_left; /* bytes left in XMIT queue */
+ unsigned char *tx_buffer;
+};
+
+static int
+qca_tty_receive(struct serdev_device *serdev, const unsigned char *data,
+ size_t count)
+{
+ struct qcauart *qca = serdev_device_get_drvdata(serdev);
+ struct net_device *netdev = qca->net_dev;
+ struct net_device_stats *n_stats = &netdev->stats;
+ size_t i;
+
+ if (!qca->rx_skb) {
+ qca->rx_skb = netdev_alloc_skb_ip_align(netdev,
+ netdev->mtu +
+ VLAN_ETH_HLEN);
+ if (!qca->rx_skb) {
+ n_stats->rx_errors++;
+ n_stats->rx_dropped++;
+ return 0;
+ }
+ }
+
+ for (i = 0; i < count; i++) {
+ s32 retcode;
+
+ retcode = qcafrm_fsm_decode(&qca->frm_handle,
+ qca->rx_skb->data,
+ skb_tailroom(qca->rx_skb),
+ data[i]);
+
+ switch (retcode) {
+ case QCAFRM_GATHER:
+ case QCAFRM_NOHEAD:
+ break;
+ case QCAFRM_NOTAIL:
+ netdev_dbg(netdev, "recv: no RX tail\n");
+ n_stats->rx_errors++;
+ n_stats->rx_dropped++;
+ break;
+ case QCAFRM_INVLEN:
+ netdev_dbg(netdev, "recv: invalid RX length\n");
+ n_stats->rx_errors++;
+ n_stats->rx_dropped++;
+ break;
+ default:
+ n_stats->rx_packets++;
+ n_stats->rx_bytes += retcode;
+ skb_put(qca->rx_skb, retcode);
+ qca->rx_skb->protocol = eth_type_trans(
+ qca->rx_skb, qca->rx_skb->dev);
+ qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
+ netif_rx_ni(qca->rx_skb);
+ qca->rx_skb = netdev_alloc_skb_ip_align(netdev,
+ netdev->mtu +
+ VLAN_ETH_HLEN);
+ if (!qca->rx_skb) {
+ netdev_dbg(netdev, "recv: out of RX resources\n");
+ n_stats->rx_errors++;
+ return i;
+ }
+ }
+ }
+
+ return i;
+}
+
+/* Write out any remaining transmit buffer. Scheduled when tty is writable */
+static void qcauart_transmit(struct work_struct *work)
+{
+ struct qcauart *qca = container_of(work, struct qcauart, tx_work);
+ struct net_device_stats *n_stats = &qca->net_dev->stats;
+ int written;
+
+ spin_lock_bh(&qca->lock);
+
+ /* First make sure we're connected. */
+ if (!netif_running(qca->net_dev)) {
+ spin_unlock_bh(&qca->lock);
+ return;
+ }
+
+ if (qca->tx_left <= 0) {
+ /* Now serial buffer is almost free & we can start
+ * transmission of another packet
+ */
+ n_stats->tx_packets++;
+ spin_unlock_bh(&qca->lock);
+ netif_wake_queue(qca->net_dev);
+ return;
+ }
+
+ written = serdev_device_write_buf(qca->serdev, qca->tx_head,
+ qca->tx_left);
+ if (written > 0) {
+ qca->tx_left -= written;
+ qca->tx_head += written;
+ }
+ spin_unlock_bh(&qca->lock);
+}
+
+/* Called by the driver when there's room for more data.
+ * Schedule the transmit.
+ */
+static void qca_tty_wakeup(struct serdev_device *serdev)
+{
+ struct qcauart *qca = serdev_device_get_drvdata(serdev);
+
+ schedule_work(&qca->tx_work);
+}
+
+static struct serdev_device_ops qca_serdev_ops = {
+ .receive_buf = qca_tty_receive,
+ .write_wakeup = qca_tty_wakeup,
+};
+
+static int qcauart_netdev_open(struct net_device *dev)
+{
+ struct qcauart *qca = netdev_priv(dev);
+
+ netif_start_queue(qca->net_dev);
+
+ return 0;
+}
+
+static int qcauart_netdev_close(struct net_device *dev)
+{
+ struct qcauart *qca = netdev_priv(dev);
+
+ spin_lock_bh(&qca->lock);
+ netif_stop_queue(dev);
+ qca->tx_left = 0;
+ spin_unlock_bh(&qca->lock);
+
+ return 0;
+}
+
+static netdev_tx_t
+qcauart_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct net_device_stats *n_stats = &dev->stats;
+ struct qcauart *qca = netdev_priv(dev);
+ u8 pad_len = 0;
+ int written;
+ u8 *pos;
+
+ spin_lock(&qca->lock);
+
+ WARN_ON(qca->tx_left);
+
+ if (!netif_running(dev)) {
+ spin_unlock(&qca->lock);
+ netdev_warn(qca->net_dev, "xmit: iface is down\n");
+ goto out;
+ }
+
+ pos = qca->tx_buffer;
+
+ if (skb->len < QCAFRM_MIN_LEN)
+ pad_len = QCAFRM_MIN_LEN - skb->len;
+
+ pos += qcafrm_create_header(pos, skb->len + pad_len);
+
+ memcpy(pos, skb->data, skb->len);
+ pos += skb->len;
+
+ if (pad_len) {
+ memset(pos, 0, pad_len);
+ pos += pad_len;
+ }
+
+ pos += qcafrm_create_footer(pos);
+
+ netif_stop_queue(qca->net_dev);
+
+ written = serdev_device_write_buf(qca->serdev, qca->tx_buffer,
+ pos - qca->tx_buffer);
+ if (written > 0) {
+ qca->tx_left = (pos - qca->tx_buffer) - written;
+ qca->tx_head = qca->tx_buffer + written;
+ n_stats->tx_bytes += written;
+ }
+ spin_unlock(&qca->lock);
+
+ netif_trans_update(dev);
+out:
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+}
+
+static void qcauart_netdev_tx_timeout(struct net_device *dev)
+{
+ struct qcauart *qca = netdev_priv(dev);
+
+ netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
+ jiffies, dev_trans_start(dev));
+ dev->stats.tx_errors++;
+ dev->stats.tx_dropped++;
+}
+
+static int qcauart_netdev_init(struct net_device *dev)
+{
+ struct qcauart *qca = netdev_priv(dev);
+ size_t len;
+
+ /* Finish setting up the device info. */
+ dev->mtu = QCAFRM_MAX_MTU;
+ dev->type = ARPHRD_ETHER;
+
+ qca->rx_skb = netdev_alloc_skb_ip_align(qca->net_dev,
+ qca->net_dev->mtu +
+ VLAN_ETH_HLEN);
+ if (!qca->rx_skb)
+ return -ENOBUFS;
+
+ len = QCAFRM_HEADER_LEN + QCAFRM_MAX_LEN + QCAFRM_FOOTER_LEN;
+ qca->tx_buffer = kmalloc(len, GFP_KERNEL);
+ if (!qca->tx_buffer)
+ return -ENOBUFS;
+
+ return 0;
+}
+
+static void qcauart_netdev_uninit(struct net_device *dev)
+{
+ struct qcauart *qca = netdev_priv(dev);
+
+ kfree(qca->tx_buffer);
+ if (qca->rx_skb)
+ dev_kfree_skb(qca->rx_skb);
+}
+
+static const struct net_device_ops qcauart_netdev_ops = {
+ .ndo_init = qcauart_netdev_init,
+ .ndo_uninit = qcauart_netdev_uninit,
+ .ndo_open = qcauart_netdev_open,
+ .ndo_stop = qcauart_netdev_close,
+ .ndo_start_xmit = qcauart_netdev_xmit,
+ .ndo_set_mac_address = eth_mac_addr,
+ .ndo_tx_timeout = qcauart_netdev_tx_timeout,
+ .ndo_validate_addr = eth_validate_addr,
+};
+
+static void qcauart_netdev_setup(struct net_device *dev)
+{
+ struct qcauart *qca;
+
+ dev->netdev_ops = &qcauart_netdev_ops;
+ dev->watchdog_timeo = QCAUART_TX_TIMEOUT;
+ dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+ dev->tx_queue_len = 100;
+
+ /* MTU range: 46 - 1500 */
+ dev->min_mtu = QCAFRM_MIN_MTU;
+ dev->max_mtu = QCAFRM_MAX_MTU;
+
+ qca = netdev_priv(dev);
+ memset(qca, 0, sizeof(struct qcauart));
+}
+
+static const struct of_device_id qca_uart_of_match[] = {
+ {
+ .compatible = "qca,qca7000-uart",
+ },
+ {}
+};
+MODULE_DEVICE_TABLE(of, qca_uart_of_match);
+
+static int qca_uart_probe(struct serdev_device *serdev)
+{
+ struct net_device *qcauart_dev = alloc_etherdev(sizeof(struct qcauart));
+ struct qcauart *qca;
+ const char *mac;
+ u32 speed = 115200;
+ int ret;
+
+ if (!qcauart_dev)
+ return -ENOMEM;
+
+ qcauart_netdev_setup(qcauart_dev);
+
+ qca = netdev_priv(qcauart_dev);
+ if (!qca) {
+ pr_err("qca_uart: Fail to retrieve private structure\n");
+ ret = -ENOMEM;
+ goto free;
+ }
+ qca->net_dev = qcauart_dev;
+ qca->serdev = serdev;
+ qcafrm_fsm_init_uart(&qca->frm_handle);
+
+ spin_lock_init(&qca->lock);
+ INIT_WORK(&qca->tx_work, qcauart_transmit);
+
+ of_property_read_u32(serdev->dev.of_node, "current-speed", &speed);
+
+ mac = of_get_mac_address(serdev->dev.of_node);
+
+ if (mac)
+ ether_addr_copy(qca->net_dev->dev_addr, mac);
+
+ if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
+ eth_hw_addr_random(qca->net_dev);
+ dev_info(&serdev->dev, "Using random MAC address: %pM\n",
+ qca->net_dev->dev_addr);
+ }
+
+ netif_carrier_on(qca->net_dev);
+ serdev_device_set_drvdata(serdev, qca);
+ serdev_device_set_client_ops(serdev, &qca_serdev_ops);
+
+ ret = serdev_device_open(serdev);
+ if (ret) {
+ dev_err(&serdev->dev, "Unable to open device %s\n",
+ qcauart_dev->name);
+ goto free;
+ }
+
+ speed = serdev_device_set_baudrate(serdev, speed);
+ dev_info(&serdev->dev, "Using baudrate: %u\n", speed);
+
+ serdev_device_set_flow_control(serdev, false);
+
+ ret = register_netdev(qcauart_dev);
+ if (ret) {
+ dev_err(&serdev->dev, "Unable to register net device %s\n",
+ qcauart_dev->name);
+ goto free;
+ }
+
+ return 0;
+
+free:
+ free_netdev(qcauart_dev);
+ return ret;
+}
+
+static void qca_uart_remove(struct serdev_device *serdev)
+{
+ struct qcauart *qca = serdev_device_get_drvdata(serdev);
+
+ /* Flush any pending characters in the driver. */
+ serdev_device_close(serdev);
+
+ netif_carrier_off(qca->net_dev);
+ unregister_netdev(qca->net_dev);
+ free_netdev(qca->net_dev);
+}
+
+static struct serdev_device_driver qca_uart_driver = {
+ .probe = qca_uart_probe,
+ .remove = qca_uart_remove,
+ .driver = {
+ .name = QCAUART_DRV_NAME,
+ .of_match_table = of_match_ptr(qca_uart_of_match),
+ },
+};
+
+module_serdev_device_driver(qca_uart_driver);
+
+MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 UART Driver");
+MODULE_AUTHOR("Qualcomm Atheros Communications");
+MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_VERSION(QCAUART_DRV_VERSION);
--
2.1.4