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Date:      Sat, 22 Aug 2015 14:23:33 -0400
From:      Brian Fundakowski Feldman <brianfundakowskifeldman@gmail.com>
To:        Tom Jones <jones@sdf.org>, loos@freebsd.org
Cc:        embedded@freebsd.org
Subject:   Re: spigen(4) SPI Generic IO interface -- need comments
Message-ID:  <CAEv1%2BOXe4w8hJXQu2MsoMLz6ixeG3hU3BmLZpssG15SaPd9JGw@mail.gmail.com>
In-Reply-To: <CAEv1%2BOUhSAJxxWAfW2GUFVw=H-_KOs2dGg2d7uhZnFbqsHE5Qw@mail.gmail.com>
References:  <CAEv1%2BOU4cFpMpeQGfnCP7L4Q_k18rOSOA9JBnKUa99DS5dFnWA@mail.gmail.com> <20150817160423.GB3078@gmail.com> <CAEv1%2BOUhSAJxxWAfW2GUFVw=H-_KOs2dGg2d7uhZnFbqsHE5Qw@mail.gmail.com>

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[-- Attachment #1 --]
I've added a couple more features:
 * clock adjustment via ioctl, independent per spigenN device
 * mmap(2) support for very low latency

On Tue, Aug 18, 2015 at 6:47 PM, Brian Fundakowski Feldman <
brianfundakowskifeldman@gmail.com> wrote:

> On Mon, Aug 17, 2015 at 12:04 PM Tom Jones <jones@sdf.org> wrote:
>
>> On Mon, Aug 17, 2015 at 10:00:26AM -0400, Brian Fundakowski Feldman wrote:
>> > I'm woefully out-of-practice with my kernel hackery (but still pretty
>> > proficient in jiggery-pokery) so I would like to get comments on a
>> little
>> > driver I just made for interfacing arbitrarily in userland with SPI
>> > components.  The only thing I'm exposing is a /dev/spigenN node with a
>> > single transfer ioctl and I put together a test circuit and program
>> with an
>> > MCP3008 10-bit ADC IC to validate that it basically works, other than
>> the
>> > limitation that the transfers must be octet-multiply-sized, but I
>> haven't
>> > looked at the SoC's (I'm using a Raspberry Pi 2) data sheet to tell
>> whether
>> > that's just a limit on the spibus(4) interface or the Broadcom SPI
>> driver
>> > or the Broadcom SoC itself.
>> >
>> > I hit one snag in development where I simply called the ioctl wrong and
>> > found copyin(9) to page fault HARD if given a bogus user address to copy
>> > from, and panic the kernel.  I can post up the test program if anyone
>> wants
>> > but it's very trivial: I just align the start bit and the command data
>> into
>> > the least significant bits of the first octet, shift it up two
>> positions so
>> > the NULs get clocked out as part of the command field, and provide two
>> > octets for the data field to retrieve back the 10-bit digital value.
>>
>> Oh, cool.
>>
>> I did the same earlier this year, have you seen[1]?.
>>
>> The FreeBSD i2c api is the same/very similar the linux one[2][3]. Have you
>> considered adding some of the ioctls[3] or the data structures to make it
>> easier to port code?
>>
>> [1]:
>> https://lists.freebsd.org/pipermail/freebsd-embedded/2015-April/002466.html
>> [2]: https://www.kernel.org/doc/Documentation/i2c/dev-interface
>> [3]:
>> https://www.freebsd.org/cgi/man.cgi?query=iic&apropos=0&sektion=0&manpath=FreeBSD+10.2-RELEASE&arch=default&format=html
>> [4]: https://www.kernel.org/doc/Documentation/spi/spidev
>
>
> I've iterated a bit on this to try to make some more sensible API,
> behaving reasonably about being able to set the SPI clock speed.  I'm going
> to implement an mmap handler so I can have my low-latency operation mode,
> as well.  I don't like the Linux APIs one bit because it's just not safe to
> allow all those configuration changes on a per-transfer basis...
>
> Moving this to -embedded because it's more apt than -hackers.
>

[-- Attachment #2 --]
Index: arm/broadcom/bcm2835/bcm2835_spi.c
===================================================================
--- arm/broadcom/bcm2835/bcm2835_spi.c	(revision 286890)
+++ arm/broadcom/bcm2835/bcm2835_spi.c	(working copy)
@@ -107,6 +107,25 @@
 	BCM_SPI_WRITE(sc, off, reg);
 }
 
+/*
+ * Set the clock speed register and return the clock speed actually used,
+ * after corrections to fit within SPI_CORE_CLK.
+ */
+static uint32_t
+bcm_spi_set_clock_speed(struct bcm_spi_softc *sc, const uint32_t clock_speed)
+{
+	uint32_t clk = SPI_CORE_CLK / clock_speed;
+
+	if (clk <= 1)
+		clk = 2;
+	else if (clk % 2)
+		clk--;
+	if (clk > 0xffff)
+		clk = 0;
+	BCM_SPI_WRITE(sc, SPI_CLK, clk);
+	return (clk == 0 ? 0 : SPI_CORE_CLK / clk);
+}
+
 static int
 bcm_spi_clock_proc(SYSCTL_HANDLER_ARGS)
 {
@@ -117,26 +136,19 @@
 	sc = (struct bcm_spi_softc *)arg1;
 
 	BCM_SPI_LOCK(sc);
-	clk = BCM_SPI_READ(sc, SPI_CLK);
+	clk = sc->sc_clock_speed;
 	BCM_SPI_UNLOCK(sc);
-	clk &= 0xffff;
-	if (clk == 0)
-		clk = 65536;
-	clk = SPI_CORE_CLK / clk;
 
 	error = sysctl_handle_int(oidp, &clk, sizeof(clk), req);
 	if (error != 0 || req->newptr == NULL)
 		return (error);
 
-	clk = SPI_CORE_CLK / clk;
-	if (clk <= 1)
-		clk = 2;
-	else if (clk % 2)
-		clk--;
-	if (clk > 0xffff)
-		clk = 0;
 	BCM_SPI_LOCK(sc);
-	BCM_SPI_WRITE(sc, SPI_CLK, clk);
+	if (sc->sc_flags & BCM_SPI_BUSY) {
+		BCM_SPI_UNLOCK(sc);
+		return (EBUSY);
+	}
+	sc->sc_clock_speed = bcm_spi_set_clock_speed(sc, clk);
 	BCM_SPI_UNLOCK(sc);
 
 	return (0);
@@ -310,7 +322,8 @@
 	BCM_SPI_WRITE(sc, SPI_CS, SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO);
 
 	/* Set the SPI clock to 500Khz. */
-	BCM_SPI_WRITE(sc, SPI_CLK, SPI_CORE_CLK / 500000);
+	sc->sc_clock_speed = 500000;
+	BCM_SPI_WRITE(sc, SPI_CLK, SPI_CORE_CLK / sc->sc_clock_speed);
 
 #ifdef	BCM_SPI_DEBUG
 	bcm_spi_printr(dev);
@@ -418,6 +431,7 @@
 bcm_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
 {
 	struct bcm_spi_softc *sc;
+	const uint32_t clock_speed_hz = cmd->clock_speed_hz;
 	int cs, err;
 
 	sc = device_get_softc(dev);
@@ -450,6 +464,10 @@
 	    SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO,
 	    SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO);
 
+	/* Switch clock speed if necessary. */
+	if (clock_speed_hz != 0 && clock_speed_hz != sc->sc_clock_speed)
+		bcm_spi_set_clock_speed(sc, clock_speed_hz);
+
 	/* Save a pointer to the SPI command. */
 	sc->sc_cmd = cmd;
 	sc->sc_read = 0;
@@ -470,6 +488,10 @@
 	/* Make sure the SPI engine and interrupts are disabled. */
 	bcm_spi_modifyreg(sc, SPI_CS, SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD, 0);
 
+	/* Switch the clock speed back if necessary. */
+	if (clock_speed_hz != 0 && clock_speed_hz != sc->sc_clock_speed)
+		bcm_spi_set_clock_speed(sc, sc->sc_clock_speed);
+
 	/* Release the controller and wakeup the next thread waiting for it. */
 	sc->sc_flags = 0;
 	wakeup_one(dev);
@@ -487,6 +509,7 @@
 	return (err);
 }
 
+
 static phandle_t
 bcm_spi_get_node(device_t bus, device_t dev)
 {
Index: arm/broadcom/bcm2835/bcm2835_spivar.h
===================================================================
--- arm/broadcom/bcm2835/bcm2835_spivar.h	(revision 286890)
+++ arm/broadcom/bcm2835/bcm2835_spivar.h	(working copy)
@@ -54,6 +54,7 @@
 	uint32_t		sc_read;
 	uint32_t		sc_flags;
 	uint32_t		sc_written;
+	uint32_t		sc_clock_speed;
 	void *			sc_intrhand;
 };
 
Index: arm/lpc/ssd1289.c
===================================================================
--- arm/lpc/ssd1289.c	(revision 286890)
+++ arm/lpc/ssd1289.c	(working copy)
@@ -157,7 +157,8 @@
 static __inline void
 ssd1289_spi_send(struct ssd1289_softc *sc, uint8_t *data, int len)
 {
-	struct spi_command cmd;
+	struct spi_command cmd = SPI_COMMAND_INITIALIZER;
+
 	uint8_t buffer[8];
 	cmd.tx_cmd = data;
 	cmd.tx_cmd_sz = len;
Index: conf/files
===================================================================
--- conf/files	(revision 286890)
+++ conf/files	(working copy)
@@ -2452,6 +2452,7 @@
 dev/spibus/ofw_spibus.c		optional fdt spibus
 dev/spibus/spibus.c		optional spibus				\
 	dependency	"spibus_if.h"
+dev/spibus/spigen.c		optional spibus
 dev/spibus/spibus_if.m		optional spibus
 dev/ste/if_ste.c		optional ste pci
 dev/stg/tmc18c30.c		optional stg
Index: dev/spibus/spi.h
===================================================================
--- dev/spibus/spi.h	(revision 286890)
+++ dev/spibus/spi.h	(working copy)
@@ -27,6 +27,7 @@
  */
 
 struct spi_command {
+	uint32_t clock_speed_hz;
 	void	*tx_cmd;
 	uint32_t tx_cmd_sz;
 	void	*rx_cmd;
@@ -37,4 +38,6 @@
 	uint32_t rx_data_sz;
 };
 
+#define	SPI_COMMAND_INITIALIZER	{ 0 }
+
 #define	SPI_CHIP_SELECT_HIGH	0x1		/* Chip select high (else low) */
Index: dev/spibus/spigen.c
===================================================================
--- dev/spibus/spigen.c	(revision 0)
+++ dev/spibus/spigen.c	(working copy)
@@ -0,0 +1,402 @@
+/*-
+ * Copyright (c) 2015 Brian Fundakowski Feldman.  All rights reserved.
+ *
+ * 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 AUTHOR ``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 AUTHOR 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>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mman.h>
+#include <sys/mutex.h>
+#include <sys/module.h>
+#include <sys/proc.h>
+#include <sys/rwlock.h>
+#include <sys/spigenio.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+ 
+#include <vm/vm.h>
+#include <vm/vm_extern.h>
+#include <vm/vm_object.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pager.h>
+
+#include <dev/spibus/spi.h>
+
+#include "spibus_if.h"
+
+struct spigen_softc {
+	device_t sc_dev;
+	struct cdev *sc_cdev;
+	struct mtx sc_mtx;
+	uint32_t sc_clock_speed;
+	uint32_t sc_command_length_max; /* cannot change while mmapped */
+	uint32_t sc_data_length_max;    /* cannot change while mmapped */
+	vm_object_t sc_mmap_buffer;     /* command, then data */
+	vm_offset_t sc_mmap_kvaddr;
+	size_t sc_mmap_buffer_size;
+	int sc_mmap_busy;
+};
+
+static int
+spigen_probe(device_t dev)
+{
+	device_set_desc(dev, "SPI Generic IO");
+	return (0);
+}
+
+static int spigen_open(struct cdev *, int, int, struct thread *);
+static int spigen_ioctl(struct cdev *, u_long, caddr_t, int, struct thread *);
+static int spigen_close(struct cdev *, int, int, struct thread *);
+static d_mmap_single_t spigen_mmap_single;
+
+static struct cdevsw spigen_cdevsw = {
+	.d_version =     D_VERSION,
+	.d_name =        "spigen",
+	.d_open =        spigen_open,
+	.d_ioctl =       spigen_ioctl,
+	.d_mmap_single = spigen_mmap_single,
+	.d_close =       spigen_close
+};
+
+static int
+spigen_command_length_max_proc(SYSCTL_HANDLER_ARGS)
+{
+	struct spigen_softc *sc = (struct spigen_softc *)arg1;
+	uint32_t command_length_max;
+	int error;
+
+	mtx_lock(&sc->sc_mtx);
+	command_length_max = sc->sc_command_length_max;
+	mtx_unlock(&sc->sc_mtx);
+	error = sysctl_handle_int(oidp, &command_length_max,
+	    sizeof(command_length_max), req);
+	if (error == 0 && req->newptr != NULL) {
+		mtx_lock(&sc->sc_mtx);
+		if (sc->sc_mmap_buffer != NULL)
+			error = EBUSY;
+		else
+			sc->sc_command_length_max = command_length_max;
+		mtx_unlock(&sc->sc_mtx);
+	}
+	return (error);
+}
+
+static int
+spigen_data_length_max_proc(SYSCTL_HANDLER_ARGS)
+{
+	struct spigen_softc *sc = (struct spigen_softc *)arg1;
+	uint32_t data_length_max;
+	int error;
+
+	mtx_lock(&sc->sc_mtx);
+	data_length_max = sc->sc_data_length_max;
+	mtx_unlock(&sc->sc_mtx);
+	error = sysctl_handle_int(oidp, &data_length_max,
+	    sizeof(data_length_max), req);
+	if (error == 0 && req->newptr != NULL) {
+		mtx_lock(&sc->sc_mtx);
+		if (sc->sc_mmap_buffer != NULL)
+			error = EBUSY;
+		else
+			sc->sc_data_length_max = data_length_max;
+		mtx_unlock(&sc->sc_mtx);
+	}
+	return (error);
+}
+
+static void
+spigen_sysctl_init(struct spigen_softc *sc)
+{
+	struct sysctl_ctx_list *ctx;
+	struct sysctl_oid *tree_node;
+	struct sysctl_oid_list *tree;
+
+	/*
+	 * Add system sysctl tree/handlers.
+	 */
+	ctx = device_get_sysctl_ctx(sc->sc_dev);
+	tree_node = device_get_sysctl_tree(sc->sc_dev);
+	tree = SYSCTL_CHILDREN(tree_node);
+	SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "command_length_max",
+	    CTLFLAG_MPSAFE | CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+	    spigen_command_length_max_proc, "IU", "SPI command header portion (octets)");
+	SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "data_length_max",
+	    CTLFLAG_MPSAFE | CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc),
+	    spigen_data_length_max_proc, "IU", "SPI data trailer portion (octets)");
+}
+
+static int
+spigen_attach(device_t dev)
+{
+	struct spigen_softc *sc;
+	const int unit = device_get_unit(dev);
+
+	sc = device_get_softc(dev);
+	sc->sc_dev = dev;
+	sc->sc_cdev = make_dev(&spigen_cdevsw, unit,
+	    UID_ROOT, GID_OPERATOR, 0660, "spigen%d", unit);
+	sc->sc_cdev->si_drv1 = dev;
+	sc->sc_command_length_max = PAGE_SIZE;
+	sc->sc_data_length_max = PAGE_SIZE;
+	mtx_init(&sc->sc_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
+	spigen_sysctl_init(sc);
+
+	return (0);
+}
+
+static int 
+spigen_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
+{
+
+	return (0);
+}
+
+static int
+spigen_transfer(struct cdev *cdev, struct spigen_transfer *st)
+{
+	struct spi_command transfer = SPI_COMMAND_INITIALIZER;
+	device_t dev = cdev->si_drv1;
+	struct spigen_softc *sc = device_get_softc(dev);
+	int error = 0;
+
+	mtx_lock(&sc->sc_mtx);
+	if (st->st_command.iov_len == 0 || st->st_data.iov_len == 0)
+		error = EINVAL;
+	else if (st->st_command.iov_len > sc->sc_command_length_max ||
+	    st->st_data.iov_len > sc->sc_data_length_max)
+		error = ENOMEM;
+	else
+		transfer.clock_speed_hz = sc->sc_clock_speed;
+	mtx_unlock(&sc->sc_mtx);
+	if (error)
+		return (error);
+	
+#if 0
+	device_printf(dev, "cmd %p %u data %p %u\n", st->st_command.iov_base,
+	    st->st_command.iov_len, st->st_data.iov_base, st->st_data.iov_len);
+#endif
+	transfer.tx_cmd = transfer.rx_cmd = malloc(st->st_command.iov_len,
+	    M_DEVBUF, M_WAITOK);
+	if (transfer.tx_cmd == NULL)
+		return (ENOMEM);
+	transfer.tx_data = transfer.rx_data = malloc(st->st_data.iov_len,
+	    M_DEVBUF, M_WAITOK);
+	if (transfer.tx_data == NULL) {
+		free(transfer.tx_cmd, M_DEVBUF);
+		return (ENOMEM);
+	}
+
+	error = copyin(st->st_command.iov_base, transfer.tx_cmd,
+	    transfer.tx_cmd_sz = transfer.rx_cmd_sz = st->st_command.iov_len);	
+	if (error == 0)
+		error = copyin(st->st_data.iov_base, transfer.tx_data,
+		    transfer.tx_data_sz = transfer.rx_data_sz =
+		                          st->st_data.iov_len);	
+	if (error == 0)
+		error = SPIBUS_TRANSFER(device_get_parent(dev), dev, &transfer);
+	if (error == 0) {
+		error = copyout(transfer.rx_cmd, st->st_command.iov_base,
+		    transfer.rx_cmd_sz);
+		if (error == 0)
+			error = copyout(transfer.rx_data, st->st_data.iov_base,
+			    transfer.rx_data_sz);
+	}
+
+	free(transfer.tx_cmd, M_DEVBUF);
+	free(transfer.tx_data, M_DEVBUF);
+	return (error);
+}
+
+static int
+spigen_transfer_mmapped(struct cdev *cdev, struct spigen_transfer_mmapped *stm)
+{
+	struct spi_command transfer = SPI_COMMAND_INITIALIZER;
+	device_t dev = cdev->si_drv1;
+	struct spigen_softc *sc = device_get_softc(dev);
+	int error = 0;
+
+	mtx_lock(&sc->sc_mtx);
+	if (sc->sc_mmap_busy)
+		error = EBUSY;
+	else if (stm->stm_command_length > sc->sc_command_length_max ||
+	    stm->stm_data_length > sc->sc_data_length_max)
+		error = E2BIG;
+	else if (sc->sc_mmap_buffer == NULL)
+		error = EINVAL;
+	else if (sc->sc_mmap_buffer_size <
+	    stm->stm_command_length + stm->stm_data_length)
+		error = ENOMEM;
+	else
+		transfer.clock_speed_hz = sc->sc_clock_speed;
+	if (error == 0)
+		sc->sc_mmap_busy = 1;
+	mtx_unlock(&sc->sc_mtx);
+	if (error)
+		return (error);
+	
+	transfer.tx_cmd = transfer.rx_cmd = (void *)sc->sc_mmap_kvaddr;
+	transfer.tx_cmd_sz = transfer.rx_cmd_sz = stm->stm_command_length;
+	transfer.tx_data = transfer.rx_data =
+	    (void *)(sc->sc_mmap_kvaddr + stm->stm_command_length);
+	transfer.tx_data_sz = transfer.rx_data_sz = stm->stm_data_length;
+	error = SPIBUS_TRANSFER(device_get_parent(dev), dev, &transfer);
+
+	mtx_lock(&sc->sc_mtx);
+	KASSERT(sc->sc_mmap_busy, ("mmap no longer marked busy"));
+	sc->sc_mmap_busy = 0;
+	mtx_unlock(&sc->sc_mtx);
+	return (error);
+}
+
+static int
+spigen_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
+    struct thread *td)
+{
+	device_t dev = cdev->si_drv1;
+	struct spigen_softc *sc = device_get_softc(dev);
+	int error;
+
+	switch (cmd) {
+	case SPIGENIOC_TRANSFER:
+		error = spigen_transfer(cdev, (struct spigen_transfer *)data);
+		break;
+	case SPIGENIOC_TRANSFER_MMAPPED:
+		error = spigen_transfer_mmapped(cdev, (struct spigen_transfer_mmapped *)data);
+		break;
+	case SPIGENIOC_GET_CLOCK_SPEED:
+		mtx_lock(&sc->sc_mtx);
+		*(uint32_t *)data = sc->sc_clock_speed;
+		mtx_unlock(&sc->sc_mtx);
+		error = 0;
+		break;
+	case SPIGENIOC_SET_CLOCK_SPEED:
+		mtx_lock(&sc->sc_mtx);
+		sc->sc_clock_speed = *(uint32_t *)data;
+		mtx_unlock(&sc->sc_mtx);
+		error = 0;
+		break;
+	default:
+		error = EOPNOTSUPP;
+	}
+	return (error);
+}
+
+static int
+spigen_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
+    vm_size_t size, struct vm_object **object, int nprot)
+{
+	device_t dev = cdev->si_drv1;
+	struct spigen_softc *sc = device_get_softc(dev);
+	vm_page_t *m;
+	size_t n, pages;
+
+	if (size == 0 ||
+	    (nprot & (PROT_EXEC | PROT_READ | PROT_WRITE))
+	    != (PROT_READ | PROT_WRITE))
+		return (EINVAL);
+	size = roundup2(size, PAGE_SIZE);
+	pages = size / PAGE_SIZE;
+
+	mtx_lock(&sc->sc_mtx);
+	if (sc->sc_mmap_buffer != NULL) {
+		mtx_unlock(&sc->sc_mtx);
+		return (EBUSY);
+	} else if (size > sc->sc_command_length_max + sc->sc_data_length_max) {
+		mtx_unlock(&sc->sc_mtx);
+		return (E2BIG);
+	}
+	sc->sc_mmap_buffer_size = size;
+	*offset = 0;
+	sc->sc_mmap_buffer = *object = vm_pager_allocate(OBJT_PHYS, 0, size,
+	    nprot, *offset, curthread->td_ucred);
+	m = malloc(sizeof(*m) * pages, M_TEMP, M_WAITOK);
+	VM_OBJECT_WLOCK(*object);
+	vm_object_reference_locked(*object); // kernel and userland both
+	for (n = 0; n < pages; n++) {
+		m[n] = vm_page_grab(*object, n,
+		    VM_ALLOC_NOBUSY | VM_ALLOC_ZERO | VM_ALLOC_WIRED);
+		m[n]->valid = VM_PAGE_BITS_ALL;
+	}
+	VM_OBJECT_WUNLOCK(*object);
+	sc->sc_mmap_kvaddr = kva_alloc(size);
+	pmap_qenter(sc->sc_mmap_kvaddr, m, pages);
+	free(m, M_TEMP);
+	mtx_unlock(&sc->sc_mtx);
+
+	if (*object == NULL)
+		 return (EINVAL);
+	return (0);
+}
+
+static int 
+spigen_close(struct cdev *cdev, int fflag, int devtype, struct thread *td)
+{
+	device_t dev = cdev->si_drv1;
+	struct spigen_softc *sc = device_get_softc(dev);
+
+	mtx_lock(&sc->sc_mtx);
+	if (sc->sc_mmap_buffer != NULL) {
+		pmap_qremove(sc->sc_mmap_kvaddr,
+		    sc->sc_mmap_buffer_size / PAGE_SIZE);
+		kva_free(sc->sc_mmap_kvaddr, sc->sc_mmap_buffer_size);
+		sc->sc_mmap_kvaddr = 0;
+		vm_object_deallocate(sc->sc_mmap_buffer);
+		sc->sc_mmap_buffer = NULL;
+		sc->sc_mmap_buffer_size = 0;
+	}
+	mtx_unlock(&sc->sc_mtx);
+	return (0);
+}
+
+static int
+spigen_detach(device_t dev)
+{
+
+	return (EIO);
+}
+
+static devclass_t spigen_devclass;
+
+static device_method_t spigen_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		spigen_probe),
+	DEVMETHOD(device_attach,	spigen_attach),
+	DEVMETHOD(device_detach,	spigen_detach),
+
+	{ 0, 0 }
+};
+
+static driver_t spigen_driver = {
+	"spigen",
+	spigen_methods,
+	sizeof(struct spigen_softc),
+};
+
+DRIVER_MODULE(spigen, spibus, spigen_driver, spigen_devclass, 0, 0);

Property changes on: dev/spibus/spigen.c
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Index: sys/spigenio.h
===================================================================
--- sys/spigenio.h	(revision 0)
+++ sys/spigenio.h	(working copy)
@@ -0,0 +1,52 @@
+/*-
+ * Copyright (c) 2000 Doug Rabson
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ *	$FreeBSD$
+ */
+
+#ifndef _SYS_SPIGENIO_H_
+#define _SYS_SPIGENIO_H_
+
+#include <sys/_iovec.h>
+
+struct spigen_transfer {
+	struct iovec st_command; /* master to slave */
+	struct iovec st_data;    /* slave to master and/or master to slave */
+};
+
+struct spigen_transfer_mmapped {
+	size_t stm_command_length; /* at offset 0 in mmap(2) area */
+	size_t stm_data_length;    /* at offset stm_command_length */
+};
+
+#define SPIGENIOC_BASE     'S'
+#define SPIGENIOC_TRANSFER 	   _IOW(SPIGENIOC_BASE, 0, \
+	    struct spigen_transfer)
+#define SPIGENIOC_TRANSFER_MMAPPED _IOW(SPIGENIOC_BASE, 1, \
+	    struct spigen_transfer_mmapped)
+#define SPIGENIOC_GET_CLOCK_SPEED  _IOR(SPIGENIOC_BASE, 2, uint32_t)
+#define SPIGENIOC_SET_CLOCK_SPEED  _IOW(SPIGENIOC_BASE, 3, uint32_t)
+
+#endif /* !_SYS_SPIGENIO_H_ */

Property changes on: sys/spigenio.h
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