--- /dev/null
+- CAIF SPI porting -
+
+- CAIF SPI basics:
+
+Running CAIF over SPI needs some extra setup, owing to the nature of SPI.
+Two extra GPIOs have been added in order to negotiate the transfers
+ between the master and the slave. The minimum requirement for running
+CAIF over SPI is a SPI slave chip and two GPIOs (more details below).
+Please note that running as a slave implies that you need to keep up
+with the master clock. An overrun or underrun event is fatal.
+
+- CAIF SPI framework:
+
+To make porting as easy as possible, the CAIF SPI has been divided in
+two parts. The first part (called the interface part) deals with all
+generic functionality such as length framing, SPI frame negotiation
+and SPI frame delivery and transmission. The other part is the CAIF
+SPI slave device part, which is the module that you have to write if
+you want to run SPI CAIF on a new hardware. This part takes care of
+the physical hardware, both with regard to SPI and to GPIOs.
+
+- Implementing a CAIF SPI device:
+
+ - Functionality provided by the CAIF SPI slave device:
+
+ In order to implement a SPI device you will, as a minimum,
+ need to implement the following
+ functions:
+
+ int (*init_xfer) (struct cfspi_xfer * xfer, struct cfspi_dev *dev):
+
+ This function is called by the CAIF SPI interface to give
+ you a chance to set up your hardware to be ready to receive
+ a stream of data from the master. The xfer structure contains
+ both physical and logical adresses, as well as the total length
+ of the transfer in both directions.The dev parameter can be used
+ to map to different CAIF SPI slave devices.
+
+ void (*sig_xfer) (bool xfer, struct cfspi_dev *dev):
+
+ This function is called by the CAIF SPI interface when the output
+ (SPI_INT) GPIO needs to change state. The boolean value of the xfer
+ variable indicates whether the GPIO should be asserted (HIGH) or
+ deasserted (LOW). The dev parameter can be used to map to different CAIF
+ SPI slave devices.
+
+ - Functionality provided by the CAIF SPI interface:
+
+ void (*ss_cb) (bool assert, struct cfspi_ifc *ifc);
+
+ This function is called by the CAIF SPI slave device in order to
+ signal a change of state of the input GPIO (SS) to the interface.
+ Only active edges are mandatory to be reported.
+ This function can be called from IRQ context (recommended in order
+ not to introduce latency). The ifc parameter should be the pointer
+ returned from the platform probe function in the SPI device structure.
+
+ void (*xfer_done_cb) (struct cfspi_ifc *ifc);
+
+ This function is called by the CAIF SPI slave device in order to
+ report that a transfer is completed. This function should only be
+ called once both the transmission and the reception are completed.
+ This function can be called from IRQ context (recommended in order
+ not to introduce latency). The ifc parameter should be the pointer
+ returned from the platform probe function in the SPI device structure.
+
+ - Connecting the bits and pieces:
+
+ - Filling in the SPI slave device structure:
+
+ Connect the necessary callback functions.
+ Indicate clock speed (used to calculate toggle delays).
+ Chose a suitable name (helps debugging if you use several CAIF
+ SPI slave devices).
+ Assign your private data (can be used to map to your structure).
+
+ - Filling in the SPI slave platform device structure:
+ Add name of driver to connect to ("cfspi_sspi").
+ Assign the SPI slave device structure as platform data.
+
+- Padding:
+
+In order to optimize throughput, a number of SPI padding options are provided.
+Padding can be enabled independently for uplink and downlink transfers.
+Padding can be enabled for the head, the tail and for the total frame size.
+The padding needs to be correctly configured on both sides of the link.
+The padding can be changed via module parameters in cfspi_sspi.c or via
+the sysfs directory of the cfspi_sspi driver (before device registration).
+
+- CAIF SPI device template:
+
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author: Daniel Martensson / Daniel.Martensson@stericsson.com
+ * License terms: GNU General Public License (GPL), version 2.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <net/caif/caif_spi.h>
+
+MODULE_LICENSE("GPL");
+
+struct sspi_struct {
+ struct cfspi_dev sdev;
+ struct cfspi_xfer *xfer;
+};
+
+static struct sspi_struct slave;
+static struct platform_device slave_device;
+
+static irqreturn_t sspi_irq(int irq, void *arg)
+{
+ /* You only need to trigger on an edge to the active state of the
+ * SS signal. Once a edge is detected, the ss_cb() function should be
+ * called with the parameter assert set to true. It is OK
+ * (and even advised) to call the ss_cb() function in IRQ context in
+ * order not to add any delay. */
+
+ return IRQ_HANDLED;
+}
+
+static void sspi_complete(void *context)
+{
+ /* Normally the DMA or the SPI framework will call you back
+ * in something similar to this. The only thing you need to
+ * do is to call the xfer_done_cb() function, providing the pointer
+ * to the CAIF SPI interface. It is OK to call this function
+ * from IRQ context. */
+}
+
+static int sspi_init_xfer(struct cfspi_xfer *xfer, struct cfspi_dev *dev)
+{
+ /* Store transfer info. For a normal implementation you should
+ * set up your DMA here and make sure that you are ready to
+ * receive the data from the master SPI. */
+
+ struct sspi_struct *sspi = (struct sspi_struct *)dev->priv;
+
+ sspi->xfer = xfer;
+
+ return 0;
+}
+
+void sspi_sig_xfer(bool xfer, struct cfspi_dev *dev)
+{
+ /* If xfer is true then you should assert the SPI_INT to indicate to
+ * the master that you are ready to recieve the data from the master
+ * SPI. If xfer is false then you should de-assert SPI_INT to indicate
+ * that the transfer is done.
+ */
+
+ struct sspi_struct *sspi = (struct sspi_struct *)dev->priv;
+}
+
+static void sspi_release(struct device *dev)
+{
+ /*
+ * Here you should release your SPI device resources.
+ */
+}
+
+static int __init sspi_init(void)
+{
+ /* Here you should initialize your SPI device by providing the
+ * necessary functions, clock speed, name and private data. Once
+ * done, you can register your device with the
+ * platform_device_register() function. This function will return
+ * with the CAIF SPI interface initialized. This is probably also
+ * the place where you should set up your GPIOs, interrupts and SPI
+ * resources. */
+
+ int res = 0;
+
+ /* Initialize slave device. */
+ slave.sdev.init_xfer = sspi_init_xfer;
+ slave.sdev.sig_xfer = sspi_sig_xfer;
+ slave.sdev.clk_mhz = 13;
+ slave.sdev.priv = &slave;
+ slave.sdev.name = "spi_sspi";
+ slave_device.dev.release = sspi_release;
+
+ /* Initialize platform device. */
+ slave_device.name = "cfspi_sspi";
+ slave_device.dev.platform_data = &slave.sdev;
+
+ /* Register platform device. */
+ res = platform_device_register(&slave_device);
+ if (res) {
+ printk(KERN_WARNING "sspi_init: failed to register dev.\n");
+ return -ENODEV;
+ }
+
+ return res;
+}
+
+static void __exit sspi_exit(void)
+{
+ platform_device_del(&slave_device);
+}
+
+module_init(sspi_init);
+module_exit(sspi_exit);
--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
+ * Author: Daniel Martensson / Daniel.Martensson@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2.
+ */
+
+#include <linux/version.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/debugfs.h>
+#include <linux/if_arp.h>
+#include <net/caif/caif_layer.h>
+#include <net/caif/caif_spi.h>
+
+#ifndef CONFIG_CAIF_SPI_SYNC
+#define FLAVOR "Flavour: Vanilla.\n"
+#else
+#define FLAVOR "Flavour: Master CMD&LEN at start.\n"
+#endif /* CONFIG_CAIF_SPI_SYNC */
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Martensson<daniel.martensson@stericsson.com>");
+MODULE_DESCRIPTION("CAIF SPI driver");
+
+static int spi_loop;
+module_param(spi_loop, bool, S_IRUGO);
+MODULE_PARM_DESC(spi_loop, "SPI running in loopback mode.");
+
+/* SPI frame alignment. */
+module_param(spi_frm_align, int, S_IRUGO);
+MODULE_PARM_DESC(spi_frm_align, "SPI frame alignment.");
+
+/* SPI padding options. */
+module_param(spi_up_head_align, int, S_IRUGO);
+MODULE_PARM_DESC(spi_up_head_align, "SPI uplink head alignment.");
+
+module_param(spi_up_tail_align, int, S_IRUGO);
+MODULE_PARM_DESC(spi_up_tail_align, "SPI uplink tail alignment.");
+
+module_param(spi_down_head_align, int, S_IRUGO);
+MODULE_PARM_DESC(spi_down_head_align, "SPI downlink head alignment.");
+
+module_param(spi_down_tail_align, int, S_IRUGO);
+MODULE_PARM_DESC(spi_down_tail_align, "SPI downlink tail alignment.");
+
+#ifdef CONFIG_ARM
+#define BYTE_HEX_FMT "%02X"
+#else
+#define BYTE_HEX_FMT "%02hhX"
+#endif
+
+#define SPI_MAX_PAYLOAD_SIZE 4096
+/*
+ * Threshold values for the SPI packet queue. Flowcontrol will be asserted
+ * when the number of packets exceeds HIGH_WATER_MARK. It will not be
+ * deasserted before the number of packets drops below LOW_WATER_MARK.
+ */
+#define LOW_WATER_MARK 100
+#define HIGH_WATER_MARK (LOW_WATER_MARK*5)
+
+#ifdef CONFIG_UML
+
+/*
+ * We sometimes use UML for debugging, but it cannot handle
+ * dma_alloc_coherent so we have to wrap it.
+ */
+static inline void *dma_alloc(dma_addr_t *daddr)
+{
+ return kmalloc(SPI_DMA_BUF_LEN, GFP_KERNEL);
+}
+
+static inline void dma_free(void *cpu_addr, dma_addr_t handle)
+{
+ kfree(cpu_addr);
+}
+
+#else
+
+static inline void *dma_alloc(dma_addr_t *daddr)
+{
+ return dma_alloc_coherent(NULL, SPI_DMA_BUF_LEN, daddr,
+ GFP_KERNEL);
+}
+
+static inline void dma_free(void *cpu_addr, dma_addr_t handle)
+{
+ dma_free_coherent(NULL, SPI_DMA_BUF_LEN, cpu_addr, handle);
+}
+#endif /* CONFIG_UML */
+
+#ifdef CONFIG_DEBUG_FS
+
+#define DEBUGFS_BUF_SIZE 4096
+
+static struct dentry *dbgfs_root;
+
+static inline void driver_debugfs_create(void)
+{
+ dbgfs_root = debugfs_create_dir(cfspi_spi_driver.driver.name, NULL);
+}
+
+static inline void driver_debugfs_remove(void)
+{
+ debugfs_remove(dbgfs_root);
+}
+
+static inline void dev_debugfs_rem(struct cfspi *cfspi)
+{
+ debugfs_remove(cfspi->dbgfs_frame);
+ debugfs_remove(cfspi->dbgfs_state);
+ debugfs_remove(cfspi->dbgfs_dir);
+}
+
+static int dbgfs_open(struct inode *inode, struct file *file)
+{
+ file->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t dbgfs_state(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buf;
+ int len = 0;
+ ssize_t size;
+ struct cfspi *cfspi = (struct cfspi *)file->private_data;
+
+ buf = kzalloc(DEBUGFS_BUF_SIZE, GFP_KERNEL);
+ if (!buf)
+ return 0;
+
+ /* Print out debug information. */
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "CAIF SPI debug information:\n");
+
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len), FLAVOR);
+
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "STATE: %d\n", cfspi->dbg_state);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Previous CMD: 0x%x\n", cfspi->pcmd);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Current CMD: 0x%x\n", cfspi->cmd);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Previous TX len: %d\n", cfspi->tx_ppck_len);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Previous RX len: %d\n", cfspi->rx_ppck_len);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Current TX len: %d\n", cfspi->tx_cpck_len);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Current RX len: %d\n", cfspi->rx_cpck_len);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Next TX len: %d\n", cfspi->tx_npck_len);
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Next RX len: %d\n", cfspi->rx_npck_len);
+
+ size = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+ kfree(buf);
+
+ return size;
+}
+
+static ssize_t print_frame(char *buf, size_t size, char *frm,
+ size_t count, size_t cut)
+{
+ int len = 0;
+ int i;
+ for (i = 0; i < count; i++) {
+ len += snprintf((buf + len), (size - len),
+ "[0x" BYTE_HEX_FMT "]",
+ frm[i]);
+ if ((i == cut) && (count > (cut * 2))) {
+ /* Fast forward. */
+ i = count - cut;
+ len += snprintf((buf + len), (size - len),
+ "--- %u bytes skipped ---\n",
+ (int)(count - (cut * 2)));
+ }
+
+ if ((!(i % 10)) && i) {
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "\n");
+ }
+ }
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len), "\n");
+ return len;
+}
+
+static ssize_t dbgfs_frame(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buf;
+ int len = 0;
+ ssize_t size;
+ struct cfspi *cfspi;
+
+ cfspi = (struct cfspi *)file->private_data;
+ buf = kzalloc(DEBUGFS_BUF_SIZE, GFP_KERNEL);
+ if (!buf)
+ return 0;
+
+ /* Print out debug information. */
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Current frame:\n");
+
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Tx data (Len: %d):\n", cfspi->tx_cpck_len);
+
+ len += print_frame((buf + len), (DEBUGFS_BUF_SIZE - len),
+ cfspi->xfer.va_tx,
+ (cfspi->tx_cpck_len + SPI_CMD_SZ), 100);
+
+ len += snprintf((buf + len), (DEBUGFS_BUF_SIZE - len),
+ "Rx data (Len: %d):\n", cfspi->rx_cpck_len);
+
+ len += print_frame((buf + len), (DEBUGFS_BUF_SIZE - len),
+ cfspi->xfer.va_rx,
+ (cfspi->rx_cpck_len + SPI_CMD_SZ), 100);
+
+ size = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+ kfree(buf);
+
+ return size;
+}
+
+static const struct file_operations dbgfs_state_fops = {
+ .open = dbgfs_open,
+ .read = dbgfs_state,
+ .owner = THIS_MODULE
+};
+
+static const struct file_operations dbgfs_frame_fops = {
+ .open = dbgfs_open,
+ .read = dbgfs_frame,
+ .owner = THIS_MODULE
+};
+
+static inline void dev_debugfs_add(struct cfspi *cfspi)
+{
+ cfspi->dbgfs_dir = debugfs_create_dir(cfspi->pdev->name, dbgfs_root);
+ cfspi->dbgfs_state = debugfs_create_file("state", S_IRUGO,
+ cfspi->dbgfs_dir, cfspi,
+ &dbgfs_state_fops);
+ cfspi->dbgfs_frame = debugfs_create_file("frame", S_IRUGO,
+ cfspi->dbgfs_dir, cfspi,
+ &dbgfs_frame_fops);
+}
+
+inline void cfspi_dbg_state(struct cfspi *cfspi, int state)
+{
+ cfspi->dbg_state = state;
+};
+#else
+
+static inline void driver_debugfs_create(void)
+{
+}
+
+static inline void driver_debugfs_remove(void)
+{
+}
+
+static inline void dev_debugfs_add(struct cfspi *cfspi)
+{
+}
+
+static inline void dev_debugfs_rem(struct cfspi *cfspi)
+{
+}
+
+inline void cfspi_dbg_state(struct cfspi *cfspi, int state)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static LIST_HEAD(cfspi_list);
+static spinlock_t cfspi_list_lock;
+
+/* SPI uplink head alignment. */
+static ssize_t show_up_head_align(struct device_driver *driver, char *buf)
+{
+ return sprintf(buf, "%d\n", spi_up_head_align);
+}
+
+static DRIVER_ATTR(up_head_align, S_IRUSR, show_up_head_align, NULL);
+
+/* SPI uplink tail alignment. */
+static ssize_t show_up_tail_align(struct device_driver *driver, char *buf)
+{
+ return sprintf(buf, "%d\n", spi_up_tail_align);
+}
+
+static DRIVER_ATTR(up_tail_align, S_IRUSR, show_up_tail_align, NULL);
+
+/* SPI downlink head alignment. */
+static ssize_t show_down_head_align(struct device_driver *driver, char *buf)
+{
+ return sprintf(buf, "%d\n", spi_down_head_align);
+}
+
+static DRIVER_ATTR(down_head_align, S_IRUSR, show_down_head_align, NULL);
+
+/* SPI downlink tail alignment. */
+static ssize_t show_down_tail_align(struct device_driver *driver, char *buf)
+{
+ return sprintf(buf, "%d\n", spi_down_tail_align);
+}
+
+static DRIVER_ATTR(down_tail_align, S_IRUSR, show_down_tail_align, NULL);
+
+/* SPI frame alignment. */
+static ssize_t show_frame_align(struct device_driver *driver, char *buf)
+{
+ return sprintf(buf, "%d\n", spi_frm_align);
+}
+
+static DRIVER_ATTR(frame_align, S_IRUSR, show_frame_align, NULL);
+
+int cfspi_xmitfrm(struct cfspi *cfspi, u8 *buf, size_t len)
+{
+ u8 *dst = buf;
+ caif_assert(buf);
+
+ do {
+ struct sk_buff *skb;
+ struct caif_payload_info *info;
+ int spad = 0;
+ int epad;
+
+ skb = skb_dequeue(&cfspi->chead);
+ if (!skb)
+ break;
+
+ /*
+ * Calculate length of frame including SPI padding.
+ * The payload position is found in the control buffer.
+ */
+ info = (struct caif_payload_info *)&skb->cb;
+
+ /*
+ * Compute head offset i.e. number of bytes to add to
+ * get the start of the payload aligned.
+ */
+ if (spi_up_head_align) {
+ spad = 1 + ((info->hdr_len + 1) & spi_up_head_align);
+ *dst = (u8)(spad - 1);
+ dst += spad;
+ }
+
+ /* Copy in CAIF frame. */
+ skb_copy_bits(skb, 0, dst, skb->len);
+ dst += skb->len;
+ cfspi->ndev->stats.tx_packets++;
+ cfspi->ndev->stats.tx_bytes += skb->len;
+
+ /*
+ * Compute tail offset i.e. number of bytes to add to
+ * get the complete CAIF frame aligned.
+ */
+ epad = (skb->len + spad) & spi_up_tail_align;
+ dst += epad;
+
+ dev_kfree_skb(skb);
+
+ } while ((dst - buf) < len);
+
+ return dst - buf;
+}
+
+int cfspi_xmitlen(struct cfspi *cfspi)
+{
+ struct sk_buff *skb = NULL;
+ int frm_len = 0;
+ int pkts = 0;
+
+ /*
+ * Decommit previously commited frames.
+ * skb_queue_splice_tail(&cfspi->chead,&cfspi->qhead)
+ */
+ while (skb_peek(&cfspi->chead)) {
+ skb = skb_dequeue_tail(&cfspi->chead);
+ skb_queue_head(&cfspi->qhead, skb);
+ }
+
+ do {
+ struct caif_payload_info *info = NULL;
+ int spad = 0;
+ int epad = 0;
+
+ skb = skb_dequeue(&cfspi->qhead);
+ if (!skb)
+ break;
+
+ /*
+ * Calculate length of frame including SPI padding.
+ * The payload position is found in the control buffer.
+ */
+ info = (struct caif_payload_info *)&skb->cb;
+
+ /*
+ * Compute head offset i.e. number of bytes to add to
+ * get the start of the payload aligned.
+ */
+ if (spi_up_head_align)
+ spad = 1 + ((info->hdr_len + 1) & spi_up_head_align);
+
+ /*
+ * Compute tail offset i.e. number of bytes to add to
+ * get the complete CAIF frame aligned.
+ */
+ epad = (skb->len + spad) & spi_up_tail_align;
+
+ if ((skb->len + spad + epad + frm_len) <= CAIF_MAX_SPI_FRAME) {
+ skb_queue_tail(&cfspi->chead, skb);
+ pkts++;
+ frm_len += skb->len + spad + epad;
+ } else {
+ /* Put back packet. */
+ skb_queue_head(&cfspi->qhead, skb);
+ }
+ } while (pkts <= CAIF_MAX_SPI_PKTS);
+
+ /*
+ * Send flow on if previously sent flow off
+ * and now go below the low water mark
+ */
+ if (cfspi->flow_off_sent && cfspi->qhead.qlen < cfspi->qd_low_mark &&
+ cfspi->cfdev.flowctrl) {
+ cfspi->flow_off_sent = 0;
+ cfspi->cfdev.flowctrl(cfspi->ndev, 1);
+ }
+
+ return frm_len;
+}
+
+static void cfspi_ss_cb(bool assert, struct cfspi_ifc *ifc)
+{
+ struct cfspi *cfspi = (struct cfspi *)ifc->priv;
+
+ if (!in_interrupt())
+ spin_lock(&cfspi->lock);
+ if (assert) {
+ set_bit(SPI_SS_ON, &cfspi->state);
+ set_bit(SPI_XFER, &cfspi->state);
+ } else {
+ set_bit(SPI_SS_OFF, &cfspi->state);
+ }
+ if (!in_interrupt())
+ spin_unlock(&cfspi->lock);
+
+ /* Wake up the xfer thread. */
+ wake_up_interruptible(&cfspi->wait);
+}
+
+static void cfspi_xfer_done_cb(struct cfspi_ifc *ifc)
+{
+ struct cfspi *cfspi = (struct cfspi *)ifc->priv;
+
+ /* Transfer done, complete work queue */
+ complete(&cfspi->comp);
+}
+
+static int cfspi_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct cfspi *cfspi = NULL;
+ unsigned long flags;
+ if (!dev)
+ return -EINVAL;
+
+ cfspi = netdev_priv(dev);
+
+ skb_queue_tail(&cfspi->qhead, skb);
+
+ spin_lock_irqsave(&cfspi->lock, flags);
+ if (!test_and_set_bit(SPI_XFER, &cfspi->state)) {
+ /* Wake up xfer thread. */
+ wake_up_interruptible(&cfspi->wait);
+ }
+ spin_unlock_irqrestore(&cfspi->lock, flags);
+
+ /* Send flow off if number of bytes is above high water mark */
+ if (!cfspi->flow_off_sent &&
+ cfspi->qhead.qlen > cfspi->qd_high_mark &&
+ cfspi->cfdev.flowctrl) {
+ cfspi->flow_off_sent = 1;
+ cfspi->cfdev.flowctrl(cfspi->ndev, 0);
+ }
+
+ return 0;
+}
+
+int cfspi_rxfrm(struct cfspi *cfspi, u8 *buf, size_t len)
+{
+ u8 *src = buf;
+
+ caif_assert(buf != NULL);
+
+ do {
+ int res;
+ struct sk_buff *skb = NULL;
+ int spad = 0;
+ int epad = 0;
+ u8 *dst = NULL;
+ int pkt_len = 0;
+
+ /*
+ * Compute head offset i.e. number of bytes added to
+ * get the start of the payload aligned.
+ */
+ if (spi_down_head_align) {
+ spad = 1 + *src;
+ src += spad;
+ }
+
+ /* Read length of CAIF frame (little endian). */
+ pkt_len = *src;
+ pkt_len |= ((*(src+1)) << 8) & 0xFF00;
+ pkt_len += 2; /* Add FCS fields. */
+
+ /* Get a suitable caif packet and copy in data. */
+
+ skb = netdev_alloc_skb(cfspi->ndev, pkt_len + 1);
+ caif_assert(skb != NULL);
+
+ dst = skb_put(skb, pkt_len);
+ memcpy(dst, src, pkt_len);
+ src += pkt_len;
+
+ skb->protocol = htons(ETH_P_CAIF);
+ skb_reset_mac_header(skb);
+ skb->dev = cfspi->ndev;
+
+ /*
+ * Push received packet up the stack.
+ */
+ if (!spi_loop)
+ res = netif_rx_ni(skb);
+ else
+ res = cfspi_xmit(skb, cfspi->ndev);
+
+ if (!res) {
+ cfspi->ndev->stats.rx_packets++;
+ cfspi->ndev->stats.rx_bytes += pkt_len;
+ } else
+ cfspi->ndev->stats.rx_dropped++;
+
+ /*
+ * Compute tail offset i.e. number of bytes added to
+ * get the complete CAIF frame aligned.
+ */
+ epad = (pkt_len + spad) & spi_down_tail_align;
+ src += epad;
+ } while ((src - buf) < len);
+
+ return src - buf;
+}
+
+static int cfspi_open(struct net_device *dev)
+{
+ netif_wake_queue(dev);
+ return 0;
+}
+
+static int cfspi_close(struct net_device *dev)
+{
+ netif_stop_queue(dev);
+ return 0;
+}
+static const struct net_device_ops cfspi_ops = {
+ .ndo_open = cfspi_open,
+ .ndo_stop = cfspi_close,
+ .ndo_start_xmit = cfspi_xmit
+};
+
+static void cfspi_setup(struct net_device *dev)
+{
+ struct cfspi *cfspi = netdev_priv(dev);
+ dev->features = 0;
+ dev->netdev_ops = &cfspi_ops;
+ dev->type = ARPHRD_CAIF;
+ dev->flags = IFF_NOARP | IFF_POINTOPOINT;
+ dev->tx_queue_len = 0;
+ dev->mtu = SPI_MAX_PAYLOAD_SIZE;
+ dev->destructor = free_netdev;
+ skb_queue_head_init(&cfspi->qhead);
+ skb_queue_head_init(&cfspi->chead);
+ cfspi->cfdev.link_select = CAIF_LINK_HIGH_BANDW;
+ cfspi->cfdev.use_frag = false;
+ cfspi->cfdev.use_stx = false;
+ cfspi->cfdev.use_fcs = false;
+ cfspi->ndev = dev;
+}
+
+int cfspi_spi_probe(struct platform_device *pdev)
+{
+ struct cfspi *cfspi = NULL;
+ struct net_device *ndev;
+ struct cfspi_dev *dev;
+ int res;
+ dev = (struct cfspi_dev *)pdev->dev.platform_data;
+
+ ndev = alloc_netdev(sizeof(struct cfspi),
+ "cfspi%d", cfspi_setup);
+ if (!dev)
+ return -ENODEV;
+
+ cfspi = netdev_priv(ndev);
+ netif_stop_queue(ndev);
+ cfspi->ndev = ndev;
+ cfspi->pdev = pdev;
+
+ /* Set flow info */
+ cfspi->flow_off_sent = 0;
+ cfspi->qd_low_mark = LOW_WATER_MARK;
+ cfspi->qd_high_mark = HIGH_WATER_MARK;
+
+ /* Assign the SPI device. */
+ cfspi->dev = dev;
+ /* Assign the device ifc to this SPI interface. */
+ dev->ifc = &cfspi->ifc;
+
+ /* Allocate DMA buffers. */
+ cfspi->xfer.va_tx = dma_alloc(&cfspi->xfer.pa_tx);
+ if (!cfspi->xfer.va_tx) {
+ printk(KERN_WARNING
+ "CFSPI: failed to allocate dma TX buffer.\n");
+ res = -ENODEV;
+ goto err_dma_alloc_tx;
+ }
+
+ cfspi->xfer.va_rx = dma_alloc(&cfspi->xfer.pa_rx);
+
+ if (!cfspi->xfer.va_rx) {
+ printk(KERN_WARNING
+ "CFSPI: failed to allocate dma TX buffer.\n");
+ res = -ENODEV;
+ goto err_dma_alloc_rx;
+ }
+
+ /* Initialize the work queue. */
+ INIT_WORK(&cfspi->work, cfspi_xfer);
+
+ /* Initialize spin locks. */
+ spin_lock_init(&cfspi->lock);
+
+ /* Initialize flow control state. */
+ cfspi->flow_stop = false;
+
+ /* Initialize wait queue. */
+ init_waitqueue_head(&cfspi->wait);
+
+ /* Create work thread. */
+ cfspi->wq = create_singlethread_workqueue(dev->name);
+ if (!cfspi->wq) {
+ printk(KERN_WARNING "CFSPI: failed to create work queue.\n");
+ res = -ENODEV;
+ goto err_create_wq;
+ }
+
+ /* Initialize work queue. */
+ init_completion(&cfspi->comp);
+
+ /* Create debugfs entries. */
+ dev_debugfs_add(cfspi);
+
+ /* Set up the ifc. */
+ cfspi->ifc.ss_cb = cfspi_ss_cb;
+ cfspi->ifc.xfer_done_cb = cfspi_xfer_done_cb;
+ cfspi->ifc.priv = cfspi;
+
+ /* Add CAIF SPI device to list. */
+ spin_lock(&cfspi_list_lock);
+ list_add_tail(&cfspi->list, &cfspi_list);
+ spin_unlock(&cfspi_list_lock);
+
+ /* Schedule the work queue. */
+ queue_work(cfspi->wq, &cfspi->work);
+
+ /* Register network device. */
+ res = register_netdev(ndev);
+ if (res) {
+ printk(KERN_ERR "CFSPI: Reg. error: %d.\n", res);
+ goto err_net_reg;
+ }
+ return res;
+
+ err_net_reg:
+ dev_debugfs_rem(cfspi);
+ set_bit(SPI_TERMINATE, &cfspi->state);
+ wake_up_interruptible(&cfspi->wait);
+ destroy_workqueue(cfspi->wq);
+ err_create_wq:
+ dma_free(cfspi->xfer.va_rx, cfspi->xfer.pa_rx);
+ err_dma_alloc_rx:
+ dma_free(cfspi->xfer.va_tx, cfspi->xfer.pa_tx);
+ err_dma_alloc_tx:
+ free_netdev(ndev);
+
+ return res;
+}
+
+int cfspi_spi_remove(struct platform_device *pdev)
+{
+ struct list_head *list_node;
+ struct list_head *n;
+ struct cfspi *cfspi = NULL;
+ struct cfspi_dev *dev;
+
+ dev = (struct cfspi_dev *)pdev->dev.platform_data;
+ spin_lock(&cfspi_list_lock);
+ list_for_each_safe(list_node, n, &cfspi_list) {
+ cfspi = list_entry(list_node, struct cfspi, list);
+ /* Find the corresponding device. */
+ if (cfspi->dev == dev) {
+ /* Remove from list. */
+ list_del(list_node);
+ /* Free DMA buffers. */
+ dma_free(cfspi->xfer.va_rx, cfspi->xfer.pa_rx);
+ dma_free(cfspi->xfer.va_tx, cfspi->xfer.pa_tx);
+ set_bit(SPI_TERMINATE, &cfspi->state);
+ wake_up_interruptible(&cfspi->wait);
+ destroy_workqueue(cfspi->wq);
+ /* Destroy debugfs directory and files. */
+ dev_debugfs_rem(cfspi);
+ unregister_netdev(cfspi->ndev);
+ spin_unlock(&cfspi_list_lock);
+ return 0;
+ }
+ }
+ spin_unlock(&cfspi_list_lock);
+ return -ENODEV;
+}
+
+static void __exit cfspi_exit_module(void)
+{
+ struct list_head *list_node;
+ struct list_head *n;
+ struct cfspi *cfspi = NULL;
+
+ list_for_each_safe(list_node, n, &cfspi_list) {
+ cfspi = list_entry(list_node, struct cfspi, list);
+ platform_device_unregister(cfspi->pdev);
+ }
+
+ /* Destroy sysfs files. */
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_head_align);
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_tail_align);
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_head_align);
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_tail_align);
+ driver_remove_file(&cfspi_spi_driver.driver, &driver_attr_frame_align);
+ /* Unregister platform driver. */
+ platform_driver_unregister(&cfspi_spi_driver);
+ /* Destroy debugfs root directory. */
+ driver_debugfs_remove();
+}
+
+static int __init cfspi_init_module(void)
+{
+ int result;
+
+ /* Initialize spin lock. */
+ spin_lock_init(&cfspi_list_lock);
+
+ /* Register platform driver. */
+ result = platform_driver_register(&cfspi_spi_driver);
+ if (result) {
+ printk(KERN_ERR "Could not register platform SPI driver.\n");
+ goto err_dev_register;
+ }
+
+ /* Create sysfs files. */
+ result =
+ driver_create_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_head_align);
+ if (result) {
+ printk(KERN_ERR "Sysfs creation failed 1.\n");
+ goto err_create_up_head_align;
+ }
+
+ result =
+ driver_create_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_tail_align);
+ if (result) {
+ printk(KERN_ERR "Sysfs creation failed 2.\n");
+ goto err_create_up_tail_align;
+ }
+
+ result =
+ driver_create_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_head_align);
+ if (result) {
+ printk(KERN_ERR "Sysfs creation failed 3.\n");
+ goto err_create_down_head_align;
+ }
+
+ result =
+ driver_create_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_tail_align);
+ if (result) {
+ printk(KERN_ERR "Sysfs creation failed 4.\n");
+ goto err_create_down_tail_align;
+ }
+
+ result =
+ driver_create_file(&cfspi_spi_driver.driver,
+ &driver_attr_frame_align);
+ if (result) {
+ printk(KERN_ERR "Sysfs creation failed 5.\n");
+ goto err_create_frame_align;
+ }
+ driver_debugfs_create();
+ return result;
+
+ err_create_frame_align:
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_tail_align);
+ err_create_down_tail_align:
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_down_head_align);
+ err_create_down_head_align:
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_tail_align);
+ err_create_up_tail_align:
+ driver_remove_file(&cfspi_spi_driver.driver,
+ &driver_attr_up_head_align);
+ err_create_up_head_align:
+ err_dev_register:
+ return result;
+}
+
+module_init(cfspi_init_module);
+module_exit(cfspi_exit_module);
--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
+ * Author: Daniel Martensson / Daniel.Martensson@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2.
+ */
+#include <linux/version.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/semaphore.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/debugfs.h>
+#include <net/caif/caif_spi.h>
+
+#ifndef CONFIG_CAIF_SPI_SYNC
+#define SPI_DATA_POS SPI_CMD_SZ
+static inline int forward_to_spi_cmd(struct cfspi *cfspi)
+{
+ return cfspi->rx_cpck_len;
+}
+#else
+#define SPI_DATA_POS 0
+static inline int forward_to_spi_cmd(struct cfspi *cfspi)
+{
+ return 0;
+}
+#endif
+
+int spi_frm_align = 2;
+int spi_up_head_align = 1;
+int spi_up_tail_align;
+int spi_down_head_align = 3;
+int spi_down_tail_align = 1;
+
+#ifdef CONFIG_DEBUG_FS
+static inline void debugfs_store_prev(struct cfspi *cfspi)
+{
+ /* Store previous command for debugging reasons.*/
+ cfspi->pcmd = cfspi->cmd;
+ /* Store previous transfer. */
+ cfspi->tx_ppck_len = cfspi->tx_cpck_len;
+ cfspi->rx_ppck_len = cfspi->rx_cpck_len;
+}
+#else
+static inline void debugfs_store_prev(struct cfspi *cfspi)
+{
+}
+#endif
+
+void cfspi_xfer(struct work_struct *work)
+{
+ struct cfspi *cfspi;
+ u8 *ptr = NULL;
+ unsigned long flags;
+ int ret;
+ cfspi = container_of(work, struct cfspi, work);
+
+ /* Initialize state. */
+ cfspi->cmd = SPI_CMD_EOT;
+
+ for (;;) {
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_WAITING);
+
+ /* Wait for master talk or transmit event. */
+ wait_event_interruptible(cfspi->wait,
+ test_bit(SPI_XFER, &cfspi->state) ||
+ test_bit(SPI_TERMINATE, &cfspi->state));
+
+ if (test_bit(SPI_TERMINATE, &cfspi->state))
+ return;
+
+#if CFSPI_DBG_PREFILL
+ /* Prefill buffers for easier debugging. */
+ memset(cfspi->xfer.va_tx, 0xFF, SPI_DMA_BUF_LEN);
+ memset(cfspi->xfer.va_rx, 0xFF, SPI_DMA_BUF_LEN);
+#endif /* CFSPI_DBG_PREFILL */
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_AWAKE);
+
+ /* Check whether we have a committed frame. */
+ if (cfspi->tx_cpck_len) {
+ int len;
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_FETCH_PKT);
+
+ /* Copy commited SPI frames after the SPI indication. */
+ ptr = (u8 *) cfspi->xfer.va_tx;
+ ptr += SPI_IND_SZ;
+ len = cfspi_xmitfrm(cfspi, ptr, cfspi->tx_cpck_len);
+ WARN_ON(len != cfspi->tx_cpck_len);
+ }
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_GET_NEXT);
+
+ /* Get length of next frame to commit. */
+ cfspi->tx_npck_len = cfspi_xmitlen(cfspi);
+
+ WARN_ON(cfspi->tx_npck_len > SPI_DMA_BUF_LEN);
+
+ /*
+ * Add indication and length at the beginning of the frame,
+ * using little endian.
+ */
+ ptr = (u8 *) cfspi->xfer.va_tx;
+ *ptr++ = SPI_CMD_IND;
+ *ptr++ = (SPI_CMD_IND & 0xFF00) >> 8;
+ *ptr++ = cfspi->tx_npck_len & 0x00FF;
+ *ptr++ = (cfspi->tx_npck_len & 0xFF00) >> 8;
+
+ /* Calculate length of DMAs. */
+ cfspi->xfer.tx_dma_len = cfspi->tx_cpck_len + SPI_IND_SZ;
+ cfspi->xfer.rx_dma_len = cfspi->rx_cpck_len + SPI_CMD_SZ;
+
+ /* Add SPI TX frame alignment padding, if necessary. */
+ if (cfspi->tx_cpck_len &&
+ (cfspi->xfer.tx_dma_len % spi_frm_align)) {
+
+ cfspi->xfer.tx_dma_len += spi_frm_align -
+ (cfspi->xfer.tx_dma_len % spi_frm_align);
+ }
+
+ /* Add SPI RX frame alignment padding, if necessary. */
+ if (cfspi->rx_cpck_len &&
+ (cfspi->xfer.rx_dma_len % spi_frm_align)) {
+
+ cfspi->xfer.rx_dma_len += spi_frm_align -
+ (cfspi->xfer.rx_dma_len % spi_frm_align);
+ }
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_INIT_XFER);
+
+ /* Start transfer. */
+ ret = cfspi->dev->init_xfer(&cfspi->xfer, cfspi->dev);
+ WARN_ON(ret);
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_ACTIVE);
+
+ /*
+ * TODO: We might be able to make an assumption if this is the
+ * first loop. Make sure that minimum toggle time is respected.
+ */
+ udelay(MIN_TRANSITION_TIME_USEC);
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_SIG_ACTIVE);
+
+ /* Signal that we are ready to recieve data. */
+ cfspi->dev->sig_xfer(true, cfspi->dev);
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_XFER_DONE);
+
+ /* Wait for transfer completion. */
+ wait_for_completion(&cfspi->comp);
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_XFER_DONE);
+
+ if (cfspi->cmd == SPI_CMD_EOT) {
+ /*
+ * Clear the master talk bit. A xfer is always at
+ * least two bursts.
+ */
+ clear_bit(SPI_SS_ON, &cfspi->state);
+ }
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_INACTIVE);
+
+ /* Make sure that the minimum toggle time is respected. */
+ if (SPI_XFER_TIME_USEC(cfspi->xfer.tx_dma_len,
+ cfspi->dev->clk_mhz) <
+ MIN_TRANSITION_TIME_USEC) {
+
+ udelay(MIN_TRANSITION_TIME_USEC -
+ SPI_XFER_TIME_USEC
+ (cfspi->xfer.tx_dma_len, cfspi->dev->clk_mhz));
+ }
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_SIG_INACTIVE);
+
+ /* De-assert transfer signal. */
+ cfspi->dev->sig_xfer(false, cfspi->dev);
+
+ /* Check whether we received a CAIF packet. */
+ if (cfspi->rx_cpck_len) {
+ int len;
+
+ cfspi_dbg_state(cfspi, CFSPI_STATE_DELIVER_PKT);
+
+ /* Parse SPI frame. */
+ ptr = ((u8 *)(cfspi->xfer.va_rx + SPI_DATA_POS));
+
+ len = cfspi_rxfrm(cfspi, ptr, cfspi->rx_cpck_len);
+ WARN_ON(len != cfspi->rx_cpck_len);
+ }
+
+ /* Check the next SPI command and length. */
+ ptr = (u8 *) cfspi->xfer.va_rx;
+
+ ptr += forward_to_spi_cmd(cfspi);
+
+ cfspi->cmd = *ptr++;
+ cfspi->cmd |= ((*ptr++) << 8) & 0xFF00;
+ cfspi->rx_npck_len = *ptr++;
+ cfspi->rx_npck_len |= ((*ptr++) << 8) & 0xFF00;
+
+ WARN_ON(cfspi->rx_npck_len > SPI_DMA_BUF_LEN);
+ WARN_ON(cfspi->cmd > SPI_CMD_EOT);
+
+ debugfs_store_prev(cfspi);
+
+ /* Check whether the master issued an EOT command. */
+ if (cfspi->cmd == SPI_CMD_EOT) {
+ /* Reset state. */
+ cfspi->tx_cpck_len = 0;
+ cfspi->rx_cpck_len = 0;
+ } else {
+ /* Update state. */
+ cfspi->tx_cpck_len = cfspi->tx_npck_len;
+ cfspi->rx_cpck_len = cfspi->rx_npck_len;
+ }
+
+ /*
+ * Check whether we need to clear the xfer bit.
+ * Spin lock needed for packet insertion.
+ * Test and clear of different bits
+ * are not supported.
+ */
+ spin_lock_irqsave(&cfspi->lock, flags);
+ if (cfspi->cmd == SPI_CMD_EOT && !cfspi_xmitlen(cfspi)
+ && !test_bit(SPI_SS_ON, &cfspi->state))
+ clear_bit(SPI_XFER, &cfspi->state);
+
+ spin_unlock_irqrestore(&cfspi->lock, flags);
+ }
+}
+
+struct platform_driver cfspi_spi_driver = {
+ .probe = cfspi_spi_probe,
+ .remove = cfspi_spi_remove,
+ .driver = {
+ .name = "cfspi_sspi",
+ .owner = THIS_MODULE,
+ },
+};
projects / karo-tx-linux.git / commitdiff