/* $NetBSD: ttwoga_dma.c,v 1.12 2026/04/04 21:18:05 andvar Exp $ */

/*-
 * Copyright (c) 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>                  /* RCS ID & Copyright macro defns */

__KERNEL_RCSID(0, "$NetBSD: ttwoga_dma.c,v 1.12 2026/04/04 21:18:05 andvar Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>

#define _ALPHA_BUS_DMA_PRIVATE
#include <sys/bus.h>

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>

#include <alpha/pci/ttwogareg.h>
#include <alpha/pci/ttwogavar.h>

static bus_dma_tag_t ttwoga_dma_get_tag(bus_dma_tag_t, alpha_bus_t);

static int      ttwoga_bus_dmamap_load_sgmap(bus_dma_tag_t, bus_dmamap_t,
                    void *, bus_size_t, struct proc *, int);

static int      ttwoga_bus_dmamap_load_mbuf_sgmap(bus_dma_tag_t, bus_dmamap_t,
                    struct mbuf *, int);

static int      ttwoga_bus_dmamap_load_uio_sgmap(bus_dma_tag_t, bus_dmamap_t,
                    struct uio *, int);

static int      ttwoga_bus_dmamap_load_raw_sgmap(bus_dma_tag_t, bus_dmamap_t,
                    bus_dma_segment_t *, int, bus_size_t, int);

static void     ttwoga_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);

/*
 * Direct-mapped window: 1G at 1G
 */
#define TTWOGA_DIRECT_MAPPED_BASE       (1UL*1024UL*1024UL*1024UL)
#define TTWOGA_DIRECT_MAPPED_SIZE       (1UL*1024UL*1024UL*1024UL)

/*
 * SGMAP window: 8M at 8M
 */
#define TTWOGA_SGMAP_MAPPED_BASE        (8UL*1024UL*1024UL)
#define TTWOGA_SGMAP_MAPPED_SIZE        (8UL*1024UL*1024UL)

/* T2 has a 256-byte out-bound DMA prefetch threshold. */
#define TTWOGA_SGMAP_PFTHRESH           256

/*
 * Macro to flush the T2 Gate Array scatter/gather TLB.
 */
#define TTWOGA_TLB_INVALIDATE(tcp)                                      \
do {                                                                    \
        uint64_t temp;                                                  \
                                                                        \
        alpha_mb();                                                     \
        temp = T2GA((tcp), T2_IOCSR);                                   \
        T2GA((tcp), T2_IOCSR) = temp | IOCSR_FTLB;                      \
        alpha_mb();                                                     \
        alpha_mb();     /* MAGIC */                                     \
        T2GA((tcp), T2_IOCSR) = temp;                                   \
        alpha_mb();                                                     \
        alpha_mb();     /* MAGIC */                                     \
} while (0)

void
ttwoga_dma_init(struct ttwoga_config *tcp)
{
        bus_dma_tag_t t;

        /*
         * Initialize the DMA tag used for direct-mapped DMA.
         */
        t = &tcp->tc_dmat_direct;
        t->_cookie = tcp;
        t->_wbase = TTWOGA_DIRECT_MAPPED_BASE;
        t->_wsize = TTWOGA_DIRECT_MAPPED_SIZE;
        t->_next_window = NULL;
        t->_boundary = 0;
        t->_sgmap = NULL;
        t->_get_tag = ttwoga_dma_get_tag;
        t->_dmamap_create = _bus_dmamap_create;
        t->_dmamap_destroy = _bus_dmamap_destroy;
        t->_dmamap_load = _bus_dmamap_load_direct;
        t->_dmamap_load_mbuf = _bus_dmamap_load_mbuf_direct;
        t->_dmamap_load_uio = _bus_dmamap_load_uio_direct;
        t->_dmamap_load_raw = _bus_dmamap_load_raw_direct;
        t->_dmamap_unload = _bus_dmamap_unload;
        t->_dmamap_sync = _bus_dmamap_sync;

        t->_dmamem_alloc = _bus_dmamem_alloc;
        t->_dmamem_free = _bus_dmamem_free;
        t->_dmamem_map = _bus_dmamem_map;
        t->_dmamem_unmap = _bus_dmamem_unmap;
        t->_dmamem_mmap = _bus_dmamem_mmap;

        /*
         * Initialize the DMA tag used for sgmap-mapped DMA.
         */
        t = &tcp->tc_dmat_sgmap;
        t->_cookie = tcp;
        t->_wbase = TTWOGA_SGMAP_MAPPED_BASE;
        t->_wsize = TTWOGA_SGMAP_MAPPED_SIZE;
        t->_next_window = NULL;
        t->_boundary = 0;
        t->_sgmap = &tcp->tc_sgmap;
        t->_pfthresh = TTWOGA_SGMAP_PFTHRESH;
        t->_get_tag = ttwoga_dma_get_tag;
        t->_dmamap_create = alpha_sgmap_dmamap_create;
        t->_dmamap_destroy = alpha_sgmap_dmamap_destroy;
        t->_dmamap_load = ttwoga_bus_dmamap_load_sgmap;
        t->_dmamap_load_mbuf = ttwoga_bus_dmamap_load_mbuf_sgmap;
        t->_dmamap_load_uio = ttwoga_bus_dmamap_load_uio_sgmap;
        t->_dmamap_load_raw = ttwoga_bus_dmamap_load_raw_sgmap;
        t->_dmamap_unload = ttwoga_bus_dmamap_unload_sgmap;
        t->_dmamap_sync = _bus_dmamap_sync;

        t->_dmamem_alloc = _bus_dmamem_alloc;
        t->_dmamem_free = _bus_dmamem_free;
        t->_dmamem_map = _bus_dmamem_map;
        t->_dmamem_unmap = _bus_dmamem_unmap;
        t->_dmamem_mmap = _bus_dmamem_mmap;

        /*
         * Disable the SGMAP TLB, and flush it.  We reenable it if
         * we have a Sable or a Gamma with T3 or T4; Gamma with T2
         * has a TLB bug apparently severe enough to require disabling
         * it.
         */
        alpha_mb();
        T2GA(tcp, T2_IOCSR) &= ~IOCSR_ETLB;
        alpha_mb();
        alpha_mb();     /* MAGIC */

        TTWOGA_TLB_INVALIDATE(tcp);

        /*
         * XXX We might want to make sure our DMA windows don't
         * XXX overlap with PCI memory space!
         */

        /*
         * Set up window 1 as a 1G direct-mapped window
         * starting at 1G.
         */
        T2GA(tcp, T2_WBASE1) = 0;
        alpha_mb();

        T2GA(tcp, T2_WMASK1) = (TTWOGA_DIRECT_MAPPED_SIZE - 1) & WMASKx_PWM;
        alpha_mb();

        T2GA(tcp, T2_TBASE1) = 0;
        alpha_mb();

        T2GA(tcp, T2_WBASE1) = TTWOGA_DIRECT_MAPPED_BASE |
            ((TTWOGA_DIRECT_MAPPED_BASE + (TTWOGA_DIRECT_MAPPED_SIZE - 1)) >>
             WBASEx_PWxA_SHIFT) | WBASEx_PWE;
        alpha_mb();

        /*
         * Initialize the SGMAP.
         */
        alpha_sgmap_init(t, &tcp->tc_sgmap, "ttwoga_sgmap",
            TTWOGA_SGMAP_MAPPED_BASE, 0, TTWOGA_SGMAP_MAPPED_SIZE,
            sizeof(uint64_t), NULL, 0);

        /*
         * Set up window 2 as an 8MB SGMAP-mapped window
         * starting at 8MB.
         */
#ifdef DIAGNOSTIC
        if ((TTWOGA_SGMAP_MAPPED_BASE & WBASEx_PWSA) !=
            TTWOGA_SGMAP_MAPPED_BASE)
                panic("ttwoga_dma_init: SGMAP base inconsistency");
#endif
        T2GA(tcp, T2_WBASE2) = 0;
        alpha_mb();

        T2GA(tcp, T2_WMASK2) = (TTWOGA_SGMAP_MAPPED_SIZE - 1) & WMASKx_PWM;
        alpha_mb();

        T2GA(tcp, T2_TBASE2) = tcp->tc_sgmap.aps_ptpa >> 1;
        alpha_mb();

        T2GA(tcp, T2_WBASE2) = TTWOGA_SGMAP_MAPPED_BASE |
            ((TTWOGA_SGMAP_MAPPED_BASE + (TTWOGA_SGMAP_MAPPED_SIZE - 1)) >>
             WBASEx_PWxA_SHIFT) | WBASEx_SGE | WBASEx_PWE;
        alpha_mb();

        /*
         * Enable SGMAP TLB on Sable or Gamma with T3 or T4; see above.
         */
        if (alpha_implver() == ALPHA_IMPLVER_EV4 ||
            tcp->tc_rev >= TRN_T3) {
                alpha_mb();
                T2GA(tcp, T2_IOCSR) |= IOCSR_ETLB;
                alpha_mb();
                alpha_mb();     /* MAGIC */
                tcp->tc_use_tlb = 1;
        }
}

/*
 * Return the bus dma tag to be used for the specified bus type.
 * INTERNAL USE ONLY!
 */
static bus_dma_tag_t
ttwoga_dma_get_tag(bus_dma_tag_t t, alpha_bus_t bustype)
{
        struct ttwoga_config *tcp = t->_cookie;

        switch (bustype) {
        case ALPHA_BUS_PCI:
        case ALPHA_BUS_EISA:
                /*
                 * Systems with a T2 Gate Array can have 2G
                 * of memory, but we only get a direct-mapped
                 * window of 1G!
                 *
                 * XXX FIX THIS SOMEDAY!
                 */
                return (&tcp->tc_dmat_direct);

        case ALPHA_BUS_ISA:
                /*
                 * ISA doesn't have enough address bits to use
                 * the direct-mapped DMA window, so we must use
                 * SGMAPs.
                 */
                return (&tcp->tc_dmat_sgmap);

        default:
                panic("ttwoga_dma_get_tag: shouldn't be here, really...");
        }
}

/*
 * Load a T2 SGMAP-mapped DMA map with a linear buffer.
 */
static int
ttwoga_bus_dmamap_load_sgmap(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
    bus_size_t buflen, struct proc *p, int flags)
{
        struct ttwoga_config *tcp = t->_cookie;
        int error;

        error = pci_sgmap_pte64_load(t, map, buf, buflen, p, flags,
            t->_sgmap);
        if (error == 0 && tcp->tc_use_tlb)
                TTWOGA_TLB_INVALIDATE(tcp);

        return (error);
}

/*
 * Load a T2 SGMAP-mapped DMA map with an mbuf chain.
 */
static int
ttwoga_bus_dmamap_load_mbuf_sgmap(bus_dma_tag_t t, bus_dmamap_t map,
    struct mbuf *m, int flags)
{
        struct ttwoga_config *tcp = t->_cookie;
        int error;

        error = pci_sgmap_pte64_load_mbuf(t, map, m, flags, t->_sgmap);
        if (error == 0 && tcp->tc_use_tlb)
                TTWOGA_TLB_INVALIDATE(tcp);

        return (error);
}

/*
 * Load a T2 SGMAP-mapped DMA map with a uio.
 */
static int
ttwoga_bus_dmamap_load_uio_sgmap(bus_dma_tag_t t, bus_dmamap_t map,
    struct uio *uio, int flags)
{
        struct ttwoga_config *tcp = t->_cookie;
        int error;

        error = pci_sgmap_pte64_load_uio(t, map, uio, flags, t->_sgmap);
        if (error == 0 && tcp->tc_use_tlb)
                TTWOGA_TLB_INVALIDATE(tcp);

        return (error);
}

/*
 * Load a T2 SGMAP-mapped DMA map with raw memory.
 */
static int
ttwoga_bus_dmamap_load_raw_sgmap(bus_dma_tag_t t, bus_dmamap_t map,
    bus_dma_segment_t *segs, int nsegs, bus_size_t size, int flags)
{
        struct ttwoga_config *tcp = t->_cookie;
        int error;

        error = pci_sgmap_pte64_load_raw(t, map, segs, nsegs, size, flags,
            t->_sgmap);
        if (error == 0 && tcp->tc_use_tlb)
                TTWOGA_TLB_INVALIDATE(tcp);

        return (error);
}

/*
 * Unload an T2 DMA map.
 */
static void
ttwoga_bus_dmamap_unload_sgmap(bus_dma_tag_t t, bus_dmamap_t map)
{
        struct ttwoga_config *tcp = t->_cookie;

        /*
         * Invalidate any SGMAP page table entries used by this
         * mapping.
         */
        pci_sgmap_pte64_unload(t, map, t->_sgmap);
        if (tcp->tc_use_tlb)
                TTWOGA_TLB_INVALIDATE(tcp);

        /*
         * Do the generic bits of the unload.
         */
        _bus_dmamap_unload_common(t, map);
}