/* $NetBSD: dwlpx_dma.c,v 1.30 2021/06/19 16:43:11 thorpej Exp $ */

/*-
 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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: dwlpx_dma.c,v 1.30 2021/06/19 16:43:11 thorpej Exp $");

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

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

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <alpha/tlsb/tlsbreg.h>
#include <alpha/tlsb/kftxxvar.h>
#include <alpha/tlsb/kftxxreg.h>
#include <alpha/pci/dwlpxreg.h>
#include <alpha/pci/dwlpxvar.h>

static bus_dma_tag_t dwlpx_dma_get_tag(bus_dma_tag_t, alpha_bus_t);

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

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

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

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

static void     dwlpx_bus_dmamap_unload_sgmap(bus_dma_tag_t, bus_dmamap_t);

/*
 * Direct-mapped window: 2G at 2G
 */
#define DWLPx_DIRECT_MAPPED_BASE        (2UL*1024UL*1024UL*1024UL)
#define DWLPx_DIRECT_MAPPED_SIZE        (2UL*1024UL*1024UL*1024UL)

/*
 * SGMAP window A: 256M or 1G at 1G
 */
#define DWLPx_SG_MAPPED_BASE            (1*1024*1024*1024)
#define DWLPx_SG_MAPPED_SIZE(x)         ((x) * PAGE_SIZE)

/* DWLPx has a 256-byte out-bound DMA prefetch threshold. */
#define DWLPx_SG_MAPPED_PFTHRESH        256

/*
 * Set this to always use SGMAPs.
 */
#ifdef DWLPX_ALWAYS_USE_SGMAP
int     dwlpx_always_use_sgmap = 1;
#else
int     dwlpx_always_use_sgmap = 0;
#endif

void
dwlpx_dma_init(struct dwlpx_config *ccp)
{
        char *exname;
        bus_dma_tag_t t;
        uint32_t *page_table;
        int i, lim, wmask;

        /*
         * Determine size of Window C based on the amount of SGMAP
         * page table SRAM available.
         */
        if (ccp->cc_sc->dwlpx_sgmapsz == DWLPX_SG128K) {
                lim = 128 * 1024;
                wmask = PCIA_WMASK_1G;
        } else {
                lim = 32 * 1024;
                wmask = PCIA_WMASK_256M;
        }

        /*
         * Initialize the DMA tag used for direct-mapped DMA.  Chain
         * this window to the SGMAP window, because we might have
         * a lot of memory in the machine.
         */
        t = &ccp->cc_dmat_direct;
        t->_cookie = ccp;
        t->_wbase = DWLPx_DIRECT_MAPPED_BASE;
        t->_wsize = DWLPx_DIRECT_MAPPED_SIZE;
        t->_next_window = &ccp->cc_dmat_sgmap;
        t->_boundary = 0;
        t->_sgmap = NULL;
        t->_get_tag = dwlpx_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 = &ccp->cc_dmat_sgmap;
        t->_cookie = ccp;
        t->_wbase = DWLPx_SG_MAPPED_BASE;
        t->_wsize = DWLPx_SG_MAPPED_SIZE(lim);
        t->_next_window = NULL;
        t->_boundary = 0;
        t->_sgmap = &ccp->cc_sgmap;
        t->_pfthresh = DWLPx_SG_MAPPED_PFTHRESH;
        t->_get_tag = dwlpx_dma_get_tag;
        t->_dmamap_create = alpha_sgmap_dmamap_create;
        t->_dmamap_destroy = alpha_sgmap_dmamap_destroy;
        t->_dmamap_load = dwlpx_bus_dmamap_load_sgmap;
        t->_dmamap_load_mbuf = dwlpx_bus_dmamap_load_mbuf_sgmap;
        t->_dmamap_load_uio = dwlpx_bus_dmamap_load_uio_sgmap;
        t->_dmamap_load_raw = dwlpx_bus_dmamap_load_raw_sgmap;
        t->_dmamap_unload = dwlpx_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;

        /*
         * A few notes about SGMAP-mapped DMA on the DWLPx:
         *
         * The DWLPx has PCIA-resident SRAM that is used for
         * the SGMAP page table; there is no TLB.  The DWLPA
         * has room for 32K entries, yielding a total of 256M
         * of sgva space.  The DWLPB has 32K entries or 128K
         * entries, depending on TBIT, yielding either 256M or
         * 1G of sgva space.
         *
         * This sgva space must be shared across all windows
         * that wish to use SGMAP-mapped DMA; make sure to
         * adjust the "sgvabase" argument to alpha_sgmap_init()
         * accordingly if you create more than one SGMAP-mapped
         * window.  Note that sgvabase != window base.  The former
         * is used to compute indexes into the page table only.
         *
         * In the current implementation the first window is a
         * 2G window direct-mapped mapped at 2G and the second
         * window is disabled and the third window is a 256M
         * or 1GB scatter/gather map at 1GB.
         *
         * We just punt on trying to support ISA DMA.  If you want
         * try that on a TurboLaser, well, you just lose.
         */

        /*
         * Initialize the page table.
         */
        page_table =
            (uint32_t *)ALPHA_PHYS_TO_K0SEG(PCIA_SGMAP_PT + ccp->cc_sysbase);
        for (i = 0; i < lim; i++)
                page_table[i * SGMAP_PTE_SPACING] = 0;
        alpha_mb();

        /*
         * Initialize the SGMAP for window C:
         *
         *      Size: 256M or 1GB
         *      Window base: 1GB
         *      SGVA base: 0
         */
        exname = kmem_asprintf("%s_sgmap_a",
            device_xname(ccp->cc_sc->dwlpx_dev));
        alpha_sgmap_init(t, &ccp->cc_sgmap, exname, DWLPx_SG_MAPPED_BASE,
            0, DWLPx_SG_MAPPED_SIZE(lim), sizeof(uint32_t),
            (void *)page_table, 0);

        /*
         * Set up DMA windows for this DWLPx.
         *
         * Do this even for all HPCs- even for the nonexistent
         * one on hose zero of a KFTIA.
         */
        for (i = 0; i < NHPC; i++) {
                REGVAL(PCIA_WMASK_A(i) + ccp->cc_sysbase) = PCIA_WMASK_2G;
                REGVAL(PCIA_TBASE_A(i) + ccp->cc_sysbase) = 0;
                REGVAL(PCIA_WBASE_A(i) + ccp->cc_sysbase) =
                    DWLPx_DIRECT_MAPPED_BASE | PCIA_WBASE_W_EN;

                REGVAL(PCIA_WMASK_B(i) + ccp->cc_sysbase) = 0;
                REGVAL(PCIA_TBASE_B(i) + ccp->cc_sysbase) = 0;
                REGVAL(PCIA_WBASE_B(i) + ccp->cc_sysbase) = 0;

                REGVAL(PCIA_WMASK_C(i) + ccp->cc_sysbase) = wmask;
                REGVAL(PCIA_TBASE_C(i) + ccp->cc_sysbase) = 0;
                REGVAL(PCIA_WBASE_C(i) + ccp->cc_sysbase) =
                    DWLPx_SG_MAPPED_BASE | PCIA_WBASE_W_EN | PCIA_WBASE_SG_EN;
                alpha_mb();
        }
}

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

        switch (bustype) {
        case ALPHA_BUS_PCI:
        case ALPHA_BUS_EISA:
                if (dwlpx_always_use_sgmap) {
                        /*
                         * Always use SGMAPs (for testing purposes?)
                         */
                        return (&ccp->cc_dmat_sgmap);
                }
                /*
                 * Give these busses the direct-mapped window; if the
                 * address crosses the threshold, it will fall back
                 * onto the SGMAP window.
                 */
                return (&ccp->cc_dmat_direct);

        case ALPHA_BUS_ISA:
                /*
                 * Don't even bother; it's not easy, given how the
                 * page table is arranged, and it's not really worth
                 * the trouble.
                 */
                panic("dwlpx_dma_get_tag: ISA DMA?  Forget it...");
                /* NOTREACHED */

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

/*
 * Load a DWLPx SGMAP-mapped DMA map with a linear buffer.
 */
static int
dwlpx_bus_dmamap_load_sgmap(bus_dma_tag_t t, bus_dmamap_t map, void *buf, bus_size_t buflen, struct proc *p, int flags)
{

        return (pci_sgmap_pte32_load(t, map, buf, buflen, p, flags,
            t->_sgmap));
}

/*
 * Load a DWLPx SGMAP-mapped DMA map with an mbuf chain.
 */
static int
dwlpx_bus_dmamap_load_mbuf_sgmap(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m, int flags)
{

        return (pci_sgmap_pte32_load_mbuf(t, map, m, flags, t->_sgmap));
}

/*
 * Load a DWLPx SGMAP-mapped DMA map with a uio.
 */
static int
dwlpx_bus_dmamap_load_uio_sgmap(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio, int flags)
{

        return (pci_sgmap_pte32_load_uio(t, map, uio, flags, t->_sgmap));
}

/*
 * Load a DWLPx SGMAP-mapped DMA map with raw memory.
 */
static int
dwlpx_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)
{

        return (pci_sgmap_pte32_load_raw(t, map, segs, nsegs, size, flags,
            t->_sgmap));
}

/*
 * Unload a DWLPx DMA map.
 */
static void
dwlpx_bus_dmamap_unload_sgmap(bus_dma_tag_t t, bus_dmamap_t map)
{

        /*
         * Invalidate any SGMAP page table entries used by this
         * mapping.
         */
        pci_sgmap_pte32_unload(t, map, t->_sgmap);

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