caif: Add CAIF HSI Link layer driver

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

This driver implements a platform driver to accommodate for a
platform specific HSI devices. A general platform driver is not
possible as there are no HSI side Kernel API defined.
Signed-off-by: NSjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/caif/Kconfig

@@ -38,3 +38,12 @@ config CAIF_SHM
 	default n
 	---help---
 	The CAIF shared memory protocol driver for the STE UX5500 platform.
+
+config CAIF_HSI
+       tristate "CAIF HSI transport driver"
+       depends on CAIF
+       default n
+       ---help---
+       The caif low level driver for CAIF over HSI.
+       Be aware that if you enable this then you also need to
+       enable a low-level HSI driver.

drivers/net/caif/Makefile

@@ -10,3 +10,6 @@ obj-$(CONFIG_CAIF_SPI_SLAVE) += cfspi_slave.o
 # Shared memory
 caif_shm-objs := caif_shmcore.o caif_shm_u5500.o
 obj-$(CONFIG_CAIF_SHM) += caif_shm.o
+
+# HSI interface
+obj-$(CONFIG_CAIF_HSI) += caif_hsi.o

include/net/caif/caif_hsi.h

+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
+ * Author:  Daniel Martensson / daniel.martensson@stericsson.com
+ *	    Dmitry.Tarnyagin  / dmitry.tarnyagin@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#ifndef CAIF_HSI_H_
+#define CAIF_HSI_H_
+
+#include <net/caif/caif_layer.h>
+#include <net/caif/caif_device.h>
+#include <linux/atomic.h>
+
+/*
+ * Maximum number of CAIF frames that can reside in the same HSI frame.
+ */
+#define CFHSI_MAX_PKTS 15
+
+/*
+ * Maximum number of bytes used for the frame that can be embedded in the
+ * HSI descriptor.
+ */
+#define CFHSI_MAX_EMB_FRM_SZ 96
+
+/*
+ * Decides if HSI buffers should be prefilled with 0xFF pattern for easier
+ * debugging. Both TX and RX buffers will be filled before the transfer.
+ */
+#define CFHSI_DBG_PREFILL		0
+
+/* Structure describing a HSI packet descriptor. */
+#pragma pack(1) /* Byte alignment. */
+struct cfhsi_desc {
+	u8 header;
+	u8 offset;
+	u16 cffrm_len[CFHSI_MAX_PKTS];
+	u8 emb_frm[CFHSI_MAX_EMB_FRM_SZ];
+};
+#pragma pack() /* Default alignment. */
+
+/* Size of the complete HSI packet descriptor. */
+#define CFHSI_DESC_SZ (sizeof(struct cfhsi_desc))
+
+/*
+ * Size of the complete HSI packet descriptor excluding the optional embedded
+ * CAIF frame.
+ */
+#define CFHSI_DESC_SHORT_SZ (CFHSI_DESC_SZ - CFHSI_MAX_EMB_FRM_SZ)
+
+/*
+ * Maximum bytes transferred in one transfer.
+ */
+/* TODO: 4096 is temporary... */
+#define CFHSI_MAX_PAYLOAD_SZ (CFHSI_MAX_PKTS * 4096)
+
+/* Size of the complete HSI TX buffer. */
+#define CFHSI_BUF_SZ_TX (CFHSI_DESC_SZ + CFHSI_MAX_PAYLOAD_SZ)
+
+/* Size of the complete HSI RX buffer. */
+#define CFHSI_BUF_SZ_RX ((2 * CFHSI_DESC_SZ) + CFHSI_MAX_PAYLOAD_SZ)
+
+/* Bitmasks for the HSI descriptor. */
+#define CFHSI_PIGGY_DESC		(0x01 << 7)
+
+#define CFHSI_TX_STATE_IDLE			0
+#define CFHSI_TX_STATE_XFER			1
+
+#define CFHSI_RX_STATE_DESC			0
+#define CFHSI_RX_STATE_PAYLOAD			1
+
+/* Bitmasks for power management. */
+#define CFHSI_WAKE_UP				0
+#define CFHSI_WAKE_UP_ACK			1
+#define CFHSI_WAKE_DOWN_ACK			2
+#define CFHSI_AWAKE				3
+#define CFHSI_PENDING_RX			4
+#define CFHSI_SHUTDOWN				6
+#define CFHSI_FLUSH_FIFO			7
+
+#ifndef CFHSI_INACTIVITY_TOUT
+#define CFHSI_INACTIVITY_TOUT			(1 * HZ)
+#endif /* CFHSI_INACTIVITY_TOUT */
+
+#ifndef CFHSI_WAKEUP_TOUT
+#define CFHSI_WAKEUP_TOUT			(3 * HZ)
+#endif /* CFHSI_WAKEUP_TOUT */
+
+
+/* Structure implemented by the CAIF HSI driver. */
+struct cfhsi_drv {
+	void (*tx_done_cb) (struct cfhsi_drv *drv);
+	void (*rx_done_cb) (struct cfhsi_drv *drv);
+	void (*wake_up_cb) (struct cfhsi_drv *drv);
+	void (*wake_down_cb) (struct cfhsi_drv *drv);
+};
+
+/* Structure implemented by HSI device. */
+struct cfhsi_dev {
+	int (*cfhsi_up) (struct cfhsi_dev *dev);
+	int (*cfhsi_down) (struct cfhsi_dev *dev);
+	int (*cfhsi_tx) (u8 *ptr, int len, struct cfhsi_dev *dev);
+	int (*cfhsi_rx) (u8 *ptr, int len, struct cfhsi_dev *dev);
+	int (*cfhsi_wake_up) (struct cfhsi_dev *dev);
+	int (*cfhsi_wake_down) (struct cfhsi_dev *dev);
+	int (*cfhsi_fifo_occupancy)(struct cfhsi_dev *dev, size_t *occupancy);
+	int (*cfhsi_rx_cancel)(struct cfhsi_dev *dev);
+	struct cfhsi_drv *drv;
+};
+
+/* Structure implemented by CAIF HSI drivers. */
+struct cfhsi {
+	struct caif_dev_common cfdev;
+	struct net_device *ndev;
+	struct platform_device *pdev;
+	struct sk_buff_head qhead;
+	struct cfhsi_drv drv;
+	struct cfhsi_dev *dev;
+	int tx_state;
+	int rx_state;
+	int rx_len;
+	u8 *rx_ptr;
+	u8 *tx_buf;
+	u8 *rx_buf;
+	spinlock_t lock;
+	int flow_off_sent;
+	u32 q_low_mark;
+	u32 q_high_mark;
+	struct list_head list;
+	struct work_struct wake_up_work;
+	struct work_struct wake_down_work;
+	struct work_struct rx_done_work;
+	struct work_struct tx_done_work;
+	struct workqueue_struct *wq;
+	wait_queue_head_t wake_up_wait;
+	wait_queue_head_t wake_down_wait;
+	wait_queue_head_t flush_fifo_wait;
+	struct timer_list timer;
+	unsigned long bits;
+};
+
+extern struct platform_driver cfhsi_driver;
+
+#endif		/* CAIF_HSI_H_ */