caif-driver: Add CAIF-SPI Protocol driver.

This patch introduces the CAIF SPI Protocol Driver for
CAIF Link Layer.

This driver implements a platform driver to accommodate for a
platform specific SPI device. A general platform driver is not
possible as there are no SPI Slave side Kernel API defined.
A sample CAIF SPI Platform device can be found in
.../Documentation/networking/caif/spi_porting.txt

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 153 insertions, 0 deletions

diff --git a/include/net/caif/caif_spi.h b/include/net/caif/caif_spi.h
new file mode 100644
index 00000000000..ce4570dff02
--- /dev/null
+++ b/include/net/caif/caif_spi.h
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Daniel Martensson / Daniel.Martensson@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#ifndef CAIF_SPI_H_
+#define CAIF_SPI_H_
+
+#include <net/caif/caif_device.h>
+
+#define SPI_CMD_WR			0x00
+#define SPI_CMD_RD			0x01
+#define SPI_CMD_EOT			0x02
+#define SPI_CMD_IND			0x04
+
+#define SPI_DMA_BUF_LEN			8192
+
+#define WL_SZ				2	/* 16 bits. */
+#define SPI_CMD_SZ			4	/* 32 bits. */
+#define SPI_IND_SZ			4	/* 32 bits. */
+
+#define SPI_XFER			0
+#define SPI_SS_ON			1
+#define SPI_SS_OFF			2
+#define SPI_TERMINATE			3
+
+/* Minimum time between different levels is 50 microseconds. */
+#define MIN_TRANSITION_TIME_USEC	50
+
+/* Defines for calculating duration of SPI transfers for a particular
+ * number of bytes.
+ */
+#define SPI_MASTER_CLK_MHZ		13
+#define SPI_XFER_TIME_USEC(bytes, clk) (((bytes) * 8) / clk)
+
+/* Normally this should be aligned on the modem in order to benefit from full
+ * duplex transfers. However a size of 8188 provokes errors when running with
+ * the modem. These errors occur when packet sizes approaches 4 kB of data.
+ */
+#define CAIF_MAX_SPI_FRAME 4092
+
+/* Maximum number of uplink CAIF frames that can reside in the same SPI frame.
+ * This number should correspond with the modem setting. The application side
+ * CAIF accepts any number of embedded downlink CAIF frames.
+ */
+#define CAIF_MAX_SPI_PKTS 9
+
+/* Decides if SPI buffers should be prefilled with 0xFF pattern for easier
+ * debugging. Both TX and RX buffers will be filled before the transfer.
+ */
+#define CFSPI_DBG_PREFILL		0
+
+/* Structure describing a SPI transfer. */
+struct cfspi_xfer {
+	u16 tx_dma_len;
+	u16 rx_dma_len;
+	void *va_tx;
+	dma_addr_t pa_tx;
+	void *va_rx;
+	dma_addr_t pa_rx;
+};
+
+/* Structure implemented by the SPI interface. */
+struct cfspi_ifc {
+	void (*ss_cb) (bool assert, struct cfspi_ifc *ifc);
+	void (*xfer_done_cb) (struct cfspi_ifc *ifc);
+	void *priv;
+};
+
+/* Structure implemented by SPI clients. */
+struct cfspi_dev {
+	int (*init_xfer) (struct cfspi_xfer *xfer, struct cfspi_dev *dev);
+	void (*sig_xfer) (bool xfer, struct cfspi_dev *dev);
+	struct cfspi_ifc *ifc;
+	char *name;
+	u32 clk_mhz;
+	void *priv;
+};
+
+/* Enumeration describing the CAIF SPI state. */
+enum cfspi_state {
+	CFSPI_STATE_WAITING = 0,
+	CFSPI_STATE_AWAKE,
+	CFSPI_STATE_FETCH_PKT,
+	CFSPI_STATE_GET_NEXT,
+	CFSPI_STATE_INIT_XFER,
+	CFSPI_STATE_WAIT_ACTIVE,
+	CFSPI_STATE_SIG_ACTIVE,
+	CFSPI_STATE_WAIT_XFER_DONE,
+	CFSPI_STATE_XFER_DONE,
+	CFSPI_STATE_WAIT_INACTIVE,
+	CFSPI_STATE_SIG_INACTIVE,
+	CFSPI_STATE_DELIVER_PKT,
+	CFSPI_STATE_MAX,
+};
+
+/* Structure implemented by SPI physical interfaces. */
+struct cfspi {
+	struct caif_dev_common cfdev;
+	struct net_device *ndev;
+	struct platform_device *pdev;
+	struct sk_buff_head qhead;
+	struct sk_buff_head chead;
+	u16 cmd;
+	u16 tx_cpck_len;
+	u16 tx_npck_len;
+	u16 rx_cpck_len;
+	u16 rx_npck_len;
+	struct cfspi_ifc ifc;
+	struct cfspi_xfer xfer;
+	struct cfspi_dev *dev;
+	unsigned long state;
+	struct work_struct work;
+	struct workqueue_struct *wq;
+	struct list_head list;
+	int    flow_off_sent;
+	u32 qd_low_mark;
+	u32 qd_high_mark;
+	struct completion comp;
+	wait_queue_head_t wait;
+	spinlock_t lock;
+	bool flow_stop;
+#ifdef CONFIG_DEBUG_FS
+	enum cfspi_state dbg_state;
+	u16 pcmd;
+	u16 tx_ppck_len;
+	u16 rx_ppck_len;
+	struct dentry *dbgfs_dir;
+	struct dentry *dbgfs_state;
+	struct dentry *dbgfs_frame;
+#endif				/* CONFIG_DEBUG_FS */
+};
+
+extern int spi_frm_align;
+extern int spi_up_head_align;
+extern int spi_up_tail_align;
+extern int spi_down_head_align;
+extern int spi_down_tail_align;
+extern struct platform_driver cfspi_spi_driver;
+
+void cfspi_dbg_state(struct cfspi *cfspi, int state);
+int cfspi_xmitfrm(struct cfspi *cfspi, u8 *buf, size_t len);
+int cfspi_xmitlen(struct cfspi *cfspi);
+int cfspi_rxfrm(struct cfspi *cfspi, u8 *buf, size_t len);
+int cfspi_spi_remove(struct platform_device *pdev);
+int cfspi_spi_probe(struct platform_device *pdev);
+int cfspi_xmitfrm(struct cfspi *cfspi, u8 *buf, size_t len);
+int cfspi_xmitlen(struct cfspi *cfspi);
+int cfspi_rxfrm(struct cfspi *cfspi, u8 *buf, size_t len);
+void cfspi_xfer(struct work_struct *work);
+
+#endif				/* CAIF_SPI_H_ */