path: root/drivers/parisc/ccio-dma.c

/*
** ccio-dma.c:
**	DMA management routines for first generation cache-coherent machines.
**	Program U2/Uturn in "Virtual Mode" and use the I/O MMU.
**
**	(c) Copyright 2000 Grant Grundler
**	(c) Copyright 2000 Ryan Bradetich
**	(c) Copyright 2000 Hewlett-Packard Company
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
**
**  "Real Mode" operation refers to U2/Uturn chip operation.
**  U2/Uturn were designed to perform coherency checks w/o using
**  the I/O MMU - basically what x86 does.
**
**  Philipp Rumpf has a "Real Mode" driver for PCX-W machines at:
**      CVSROOT=:pserver:anonymous@198.186.203.37:/cvsroot/linux-parisc
**      cvs -z3 co linux/arch/parisc/kernel/dma-rm.c
**
**  I've rewritten his code to work under TPG's tree. See ccio-rm-dma.c.
**
**  Drawbacks of using Real Mode are:
**	o outbound DMA is slower - U2 won't prefetch data (GSC+ XQL signal).
**      o Inbound DMA less efficient - U2 can't use DMA_FAST attribute.
**	o Ability to do scatter/gather in HW is lost.
**	o Doesn't work under PCX-U/U+ machines since they didn't follow
**        the coherency design originally worked out. Only PCX-W does.
*/

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/scatterlist.h>
#include <linux/iommu-helper.h>
#include <linux/export.h>

#include <asm/byteorder.h>
#include <asm/cache.h>		/* for L1_CACHE_BYTES */
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/dma.h>
#include <asm/io.h>
#include <asm/hardware.h>       /* for register_module() */
#include <asm/parisc-device.h>

/* 
** Choose "ccio" since that's what HP-UX calls it.
** Make it easier for folks to migrate from one to the other :^)
*/
#define MODULE_NAME "ccio"

#undef DEBUG_CCIO_RES
#undef DEBUG_CCIO_RUN
#undef DEBUG_CCIO_INIT
#undef DEBUG_CCIO_RUN_SG

#ifdef CONFIG_PROC_FS
/* depends on proc fs support. But costs CPU performance. */
#undef CCIO_COLLECT_STATS
#endif

#include <asm/runway.h>		/* for proc_runway_root */

#ifdef DEBUG_CCIO_INIT
#define DBG_INIT(x...)  printk(x)
#else
#define DBG_INIT(x...)
#endif

#ifdef DEBUG_CCIO_RUN
#define DBG_RUN(x...)   printk(x)
#else
#define DBG_RUN(x...)
#endif

#ifdef DEBUG_CCIO_RES
#define DBG_RES(x...)   printk(x)
#else
#define DBG_RES(x...)
#endif

#ifdef DEBUG_CCIO_RUN_SG
#define DBG_RUN_SG(x...) printk(x)
#else
#define DBG_RUN_SG(x...)
#endif

#define CCIO_INLINE	inline
#define WRITE_U32(value, addr) __raw_writel(value, addr)
#define READ_U32(addr) __raw_readl(addr)

#define U2_IOA_RUNWAY 0x580
#define U2_BC_GSC     0x501
#define UTURN_IOA_RUNWAY 0x581
#define UTURN_BC_GSC     0x502

#define IOA_NORMAL_MODE      0x00020080 /* IO_CONTROL to turn on CCIO        */
#define CMD_TLB_DIRECT_WRITE 35         /* IO_COMMAND for I/O TLB Writes     */
#define CMD_TLB_PURGE        33         /* IO_COMMAND to Purge I/O TLB entry */

#define CCIO_MAPPING_ERROR    (~(dma_addr_t)0)

struct ioa_registers {
        /* Runway Supervisory Set */
        int32_t    unused1[12];
        uint32_t   io_command;             /* Offset 12 */
        uint32_t   io_status;              /* Offset 13 */
        uint32_t   io_control;             /* Offset 14 */
        int32_t    unused2[1];

        /* Runway Auxiliary Register Set */
        uint32_t   io_err_resp;            /* Offset  0 */
        uint32_t   io_err_info;            /* Offset  1 */
        uint32_t   io_err_req;             /* Offset  2 */
        uint32_t   io_err_resp_hi;         /* Offset  3 */
        uint32_t   io_tlb_entry_m;         /* Off