lba_pci.c

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/*
**
**  PCI Lower Bus Adapter (LBA) manager
**
**	(c) Copyright 1999,2000 Grant Grundler
**	(c) Copyright 1999,2000 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.
**
**
** This module primarily provides access to PCI bus (config/IOport
** spaces) on platforms with an SBA/LBA chipset. A/B/C/J/L/N-class
** with 4 digit model numbers - eg C3000 (and A400...sigh).
**
** LBA driver isn't as simple as the Dino driver because:
**   (a) this chip has substantial bug fixes between revisions
**       (Only one Dino bug has a software workaround :^(  )
**   (b) has more options which we don't (yet) support (DMA hints, OLARD)
**   (c) IRQ support lives in the I/O SAPIC driver (not with PCI driver)
**   (d) play nicely with both PAT and "Legacy" PA-RISC firmware (PDC).
**       (dino only deals with "Legacy" PDC)
**
** LBA driver passes the I/O SAPIC HPA to the I/O SAPIC driver.
** (I/O SAPIC is integratd in the LBA chip).
**
** FIXME: Add support to SBA and LBA drivers for DMA hint sets
** FIXME: Add support for PCI card hot-plug (OLARD).
*/

#include <linux/delay.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/init.h>		/* for __init and __devinit */
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/slab.h>

#include <asm/byteorder.h>
#include <asm/pdc.h>
#include <asm/pdcpat.h>
#include <asm/page.h>
#include <asm/system.h>

#include <asm/ropes.h>
#include <asm/hardware.h>	/* for register_parisc_driver() stuff */
#include <asm/parisc-device.h>
#include <asm/io.h>		/* read/write stuff */

#undef DEBUG_LBA	/* general stuff */
#undef DEBUG_LBA_PORT	/* debug I/O Port access */
#undef DEBUG_LBA_CFG	/* debug Config Space Access (ie PCI Bus walk) */
#undef DEBUG_LBA_PAT	/* debug PCI Resource Mgt code - PDC PAT only */

#undef FBB_SUPPORT	/* Fast Back-Back xfers - NOT READY YET */


#ifdef DEBUG_LBA
#define DBG(x...)	printk(x)
#else
#define DBG(x...)
#endif

#ifdef DEBUG_LBA_PORT
#define DBG_PORT(x...)	printk(x)
#else
#define DBG_PORT(x...)
#endif

#ifdef DEBUG_LBA_CFG
#define DBG_CFG(x...)	printk(x)
#else
#define DBG_CFG(x...)
#endif

#ifdef DEBUG_LBA_PAT
#define DBG_PAT(x...)	printk(x)
#else
#define DBG_PAT(x...)
#endif


/*
** Config accessor functions only pass in the 8-bit bus number and not
** the 8-bit "PCI Segment" number. Each LBA will be assigned a PCI bus
** number based on what firmware wrote into the scratch register.
**
** The "secondary" bus number is set to this before calling
** pci_register_ops(). If any PPB's are present, the scan will
** discover them and update the "secondary" and "subordinate"
** fields in the pci_bus structure.
**
** Changes in the configuration *may* result in a different
** bus number for each LBA depending on what firmware does.
*/

#define MODULE_NAME "LBA"

/* non-postable I/O port space, densely packed */
#define LBA_PORT_BASE	(PCI_F_EXTEND | 0xfee00000UL)
static void __iomem *astro_iop_base __read_mostly;

static u32 lba_t32;

/* lba flags */
#define LBA_FLAG_SKIP_PROBE	0x10

#define LBA_SKIP_PROBE(d) ((d)->flags & LBA_FLAG_SKIP_PROBE)


/* Looks nice and keeps the compiler happy */
#define LBA_DEV(d) ((struct lba_device *) (d))


/*
** Only allow 8 subsidiary busses per LBA
** Problem is the PCI bus numbering is globally shared.
*/
#define LBA_MAX_NUM_BUSES 8

/************************************
 * LBA register read and write support
 *
 * BE WARNED: register writes are posted.
 *  (ie follow writes which must reach HW with a read)
 */
#define READ_U8(addr)  __raw_readb(addr)
#define READ_U16(addr) __raw_readw(addr)
#define READ_U32(addr) __raw_readl(addr)
#define WRITE_U8(value, addr)  __raw_writeb(value, addr)
#define WRITE_U16(value, addr) __raw_writew(value, addr)
#define WRITE_U32(value, addr) __raw_writel(value, addr)

#define READ_REG8(addr)  readb(addr)
#define READ_REG16(addr) readw(addr)
#define READ_REG32(addr) readl(addr)
#define READ_REG64(addr) readq(addr)
#define WRITE_REG8(value, addr)  writeb(value, addr)
#define WRITE_REG16(value, addr) writew(value, addr)
#define WRITE_REG32(value, addr) writel(value, addr)


#define LBA_CFG_TOK(bus,dfn) ((u32) ((bus)<<16 | (dfn)<<8))
#define LBA_CFG_BUS(tok)  ((u8) ((tok)>>16))
#define LBA_CFG_DEV(tok)  ((u8) ((tok)>>11) & 0x1f)
#define LBA_CFG_FUNC(tok) ((u8) ((tok)>>8 ) & 0x7)


/*
** Extract LBA (Rope) number from HPA
** REVISIT: 16 ropes for Stretch/Ike?
*/
#define ROPES_PER_IOC	8
#define LBA_NUM(x)    ((((unsigned long) x) >> 13) & (ROPES_PER_IOC-1))


static void
lba_dump_res(struct resource *r, int d)
{
	int i;

	if (NULL == r)
		return;

	printk(KERN_DEBUG "(%p)", r->parent);
	for (i = d; i ; --i) printk(" ");
	printk(KERN_DEBUG "%p [%lx,%lx]/%lx\n", r,
		(long)r->start, (long)r->end, r->flags);
	lba_dump_res(r->child, d+2);
	lba_dump_res(r->sibling, d);
}


/*
** LBA rev 2.0, 2.1, 2.2, and 3.0 bus walks require a complex
** workaround for cfg cycles:
**	-- preserve  LBA state
**	-- prevent any DMA from occurring
**	-- turn on smart mode
**	-- probe with config writes before doing config reads
**	-- check ERROR_STATUS
**	-- clear ERROR_STATUS
**	-- restore LBA state
**
** The workaround is only used for device discovery.
*/

static int lba_device_present(u8 bus, u8 dfn, struct lba_device *d)
{
	u8 first_bus = d->hba.hba_bus->secondary;
	u8 last_sub_bus = d->hba.hba_bus->subordinate;

	if ((bus < first_bus) ||
	    (bus > last_sub_bus) ||
	    ((bus - first_bus) >= LBA_MAX_NUM_BUSES)) {
		return 0;
	}

	return 1;
}



#define LBA_CFG_SETUP(d, tok) {				\
    /* Save contents of error config register.  */			\
    error_config = READ_REG32(d->hba.base_addr + LBA_ERROR_CONFIG);		\
\
    /* Save contents of status control register.  */			\
    status_control = READ_REG32(d->hba.base_addr + LBA_STAT_CTL);		\
\
    /* For LBA rev 2.0, 2.1, 2.2, and 3.0, we must disable DMA		\
    ** arbitration for full bus walks.					\
    */									\
	/* Save contents of arb mask register. */			\
	arb_mask = READ_REG32(d->hba.base_addr + LBA_ARB_MASK);		\
\
	/*								\
	 * Turn off all device arbitration bits (i.e. everything	\
	 * except arbitration enable bit).				\
	 */								\
	WRITE_REG32(0x1, d->hba.base_addr + LBA_ARB_MASK);		\
\
    /*									\
     * Set the smart mode bit so that master aborts don't cause		\
     * LBA to go into PCI fatal mode (required).			\
     */									\
    WRITE_REG32(error_config | LBA_SMART_MODE, d->hba.base_addr + LBA_ERROR_CONFIG);	\
}


#define LBA_CFG_PROBE(d, tok) {				\
    /*									\
     * Setup Vendor ID write and read back the address register		\
     * to make sure that LBA is the bus master.				\
     */									\
    WRITE_REG32(tok | PCI_VENDOR_ID, (d)->hba.base_addr + LBA_PCI_CFG_ADDR);\
    /*									\
     * Read address register to ensure that LBA is the bus master,	\
     * which implies that DMA traffic has stopped when DMA arb is off.	\
     */									\
    lba_t32 = READ_REG32((d)->hba.base_addr + LBA_PCI_CFG_ADDR);	\
    /*									\
     * Generate a cfg write cycle (will have no affect on		\
     * Vendor ID register since read-only).				\
     */									\
    WRITE_REG32(~0, (d)->hba.base_addr + LBA_PCI_CFG_DATA);		\
    /*									\
     * Make sure write has completed before proceeding further,		\
     * i.e. before setting clear enable.				\
     */									\
    lba_t32 = READ_REG32((d)->hba.base_addr + LBA_PCI_CFG_ADDR);	\
}


/*
 * HPREVISIT:
 *   -- Can't tell if config cycle got the error.
 *
 *		OV bit is broken until rev 4.0, so can't use OV bit and
 *		LBA_ERROR_LOG_ADDR to tell if error belongs to config cycle.
 *
 *		As of rev 4.0, no longer need the error check.
 *
 *   -- Even if we could tell, we still want to return -1
 *	for **ANY** error (not just master abort).
 *
 *   -- Only clear non-fatal errors (we don't want to bring
 *	LBA out of pci-fatal mode).
 *
 *		Actually, there is still a race in which
 *		we could be clearing a fatal error.  We will
 *		live with this during our initial bus walk
 *		until rev 4.0 (no driver activity during
 *		initial bus walk).  The initial bus walk
 *		has race conditions concerning the use of
 *		smart mode as well.
 */

#define LBA_MASTER_ABORT_ERROR 0xc
#define LBA_FATAL_ERROR 0x10

#define LBA_CFG_MASTER_ABORT_CHECK(d, base, tok, error) {		\
    u32 error_status = 0;						\
    /*									\
     * Set clear enable (CE) bit. Unset by HW when new			\
     * errors are logged -- LBA HW ERS section 14.3.3).		\
     */									\
    WRITE_REG32(status_control | CLEAR_ERRLOG_ENABLE, base + LBA_STAT_CTL); \
    error_status = READ_REG32(base + LBA_ERROR_STATUS);		\
    if ((error_status & 0x1f) != 0) {					\
	/*								\
	 * Fail the config read request.				\
	 */								\
	error = 1;							\
	if ((error_status & LBA_FATAL_ERROR) == 0) {			\
	    /*								\
	     * Clear error status (if fatal bit not set) by setting	\
	     * clear error log bit (CL).				\
	     */								\
	    WRITE_REG32(status_control | CLEAR_ERRLOG, base + LBA_STAT_CTL); \
	}								\
    }									\
}

#define LBA_CFG_TR4_ADDR_SETUP(d, addr)					\
	WRITE_REG32(((addr) & ~3), (d)->hba.base_addr + LBA_PCI_CFG_ADDR);

#define LBA_CFG_ADDR_SETUP(d, addr) {					\
    WRITE_REG32(((addr) & ~3), (d)->hba.base_addr + LBA_PCI_CFG_ADDR);	\
    /*									\
     * Read address register to ensure that LBA is the bus master,	\
     * which implies that DMA traffic has stopped when DMA arb is off.	\
     */									\
    lba_t32 = READ_REG32((d)->hba.base_addr + LBA_PCI_CFG_ADDR);	\
}


#define LBA_CFG_RESTORE(d, base) {					\
    /*									\
     * Restore status control register (turn off clear enable).		\
     */									\
    WRITE_REG32(status_control, base + LBA_STAT_CTL);			\
    /*									\
     * Restore error config register (turn off smart mode).		\
     */									\
    WRITE_REG32(error_config, base + LBA_ERROR_CONFIG);			\
	/*								\
	 * Restore arb mask register (reenables DMA arbitration).	\
	 */								\
	WRITE_REG32(arb_mask, base + LBA_ARB_MASK);			\
}



static unsigned int
lba_rd_cfg(struct lba_device *d, u32 tok, u8 reg, u32 size)
{
	u32 data = ~0U;
	int error = 0;
	u32 arb_mask = 0;	/* used by LBA_CFG_SETUP/RESTORE */
	u32 error_config = 0;	/* used by LBA_CFG_SETUP/RESTORE */
	u32 status_control = 0;	/* used by LBA_CFG_SETUP/RESTORE */

	LBA_CFG_SETUP(d, tok);
	LBA_CFG_PROBE(d, tok);
	LBA_CFG_MASTER_ABORT_CHECK(d, d->hba.base_addr, tok, error);
	if (!error) {
		void __iomem *data_reg = d->hba.base_addr + LBA_PCI_CFG_DATA;

		LBA_CFG_ADDR_SETUP(d, tok | reg);
		switch (size) {
		case 1: data = (u32) READ_REG8(data_reg + (reg & 3)); break;
		case 2: data = (u32) READ_REG16(data_reg+ (reg & 2)); break;
		case 4: data = READ_REG32(data_reg); break;
		}
	}
	LBA_CFG_RESTORE(d, d->hba.base_addr);
	return(data);
}


static int elroy_cfg_read(struct pci_bus *bus, unsigned int devfn, int pos, int size, u32 *data)
{
	struct lba_device *d = LBA_DEV(parisc_walk_tree(bus->bridge));
	u32 local_bus = (bus->parent == NULL) ? 0 : bus->secondary;
	u32 tok = LBA_CFG_TOK(local_bus, devfn);
	void __iomem *data_reg = d->hba.base_addr + LBA_PCI_CFG_DATA;

	if ((pos > 255) || (devfn > 255))
		return -EINVAL;

/* FIXME: B2K/C3600 workaround is always use old method... */
	/* if (!LBA_SKIP_PROBE(d)) */ {
		/* original - Generate config cycle on broken elroy
		  with risk we will miss PCI bus errors. */
		*data = lba_rd_cfg(d, tok, pos, size);
		DBG_CFG("%s(%x+%2x) -> 0x%x (a)\n", __FUNCTION__, tok, pos, *data);
		return 0;
	}

	if (LBA_SKIP_PROBE(d) && !lba_device_present(bus->secondary, devfn, d)) {
		DBG_CFG("%s(%x+%2x) -> -1 (b)\n", __FUNCTION__, tok, pos);
		/* either don't want to look or know device isn't present. */
		*data = ~0U;
		return(0);
	}

	/* Basic Algorithm
	** Should only get here on fully working LBA rev.
	** This is how simple the code should have been.
	*/
	LBA_CFG_ADDR_SETUP(d, tok | pos);
	switch(size) {
	case 1: *data = READ_REG8 (data_reg + (pos & 3)); break;
	case 2: *data = READ_REG16(data_reg + (pos & 2)); break;
	case 4: *data = READ_REG32(data_reg); break;