freebsd-dev/sys/arm/broadcom/bcm2835/bcm2835_spi.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
* Copyright (c) 2013 Luiz Otavio O Souza <loos@freebsd.org>
* 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.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <machine/intr.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/spibus/spi.h>
#include <dev/spibus/spibusvar.h>
#include <arm/broadcom/bcm2835/bcm2835_spireg.h>
#include <arm/broadcom/bcm2835/bcm2835_spivar.h>
#include "spibus_if.h"
static struct ofw_compat_data compat_data[] = {
{"broadcom,bcm2835-spi", 1},
{"brcm,bcm2835-spi", 1},
{NULL, 0}
};
static void bcm_spi_intr(void *);
#ifdef BCM_SPI_DEBUG
static void
bcm_spi_printr(device_t dev)
{
struct bcm_spi_softc *sc;
uint32_t reg;
sc = device_get_softc(dev);
reg = BCM_SPI_READ(sc, SPI_CS);
device_printf(dev, "CS=%b\n", reg,
"\20\1CS0\2CS1\3CPHA\4CPOL\7CSPOL"
"\10TA\11DMAEN\12INTD\13INTR\14ADCS\15REN\16LEN"
"\21DONE\22RXD\23TXD\24RXR\25RXF\26CSPOL0\27CSPOL1"
"\30CSPOL2\31DMA_LEN\32LEN_LONG");
reg = BCM_SPI_READ(sc, SPI_CLK) & SPI_CLK_MASK;
if (reg % 2)
reg--;
if (reg == 0)
reg = 65536;
device_printf(dev, "CLK=%uMhz/%d=%luhz\n",
SPI_CORE_CLK / 1000000, reg, SPI_CORE_CLK / reg);
reg = BCM_SPI_READ(sc, SPI_DLEN) & SPI_DLEN_MASK;
device_printf(dev, "DLEN=%d\n", reg);
reg = BCM_SPI_READ(sc, SPI_LTOH) & SPI_LTOH_MASK;
device_printf(dev, "LTOH=%d\n", reg);
reg = BCM_SPI_READ(sc, SPI_DC);
device_printf(dev, "DC=RPANIC=%#x RDREQ=%#x TPANIC=%#x TDREQ=%#x\n",
(reg & SPI_DC_RPANIC_MASK) >> SPI_DC_RPANIC_SHIFT,
(reg & SPI_DC_RDREQ_MASK) >> SPI_DC_RDREQ_SHIFT,
(reg & SPI_DC_TPANIC_MASK) >> SPI_DC_TPANIC_SHIFT,
(reg & SPI_DC_TDREQ_MASK) >> SPI_DC_TDREQ_SHIFT);
}
#endif
static void
bcm_spi_modifyreg(struct bcm_spi_softc *sc, uint32_t off, uint32_t mask,
uint32_t value)
{
uint32_t reg;
mtx_assert(&sc->sc_mtx, MA_OWNED);
reg = BCM_SPI_READ(sc, off);
reg &= ~mask;
reg |= value;
BCM_SPI_WRITE(sc, off, reg);
}
static int
bcm_spi_clock_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_spi_softc *sc;
uint32_t clk;
int error;
sc = (struct bcm_spi_softc *)arg1;
BCM_SPI_LOCK(sc);
clk = BCM_SPI_READ(sc, SPI_CLK);
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);
return (0);
}
static int
bcm_spi_cs_bit_proc(SYSCTL_HANDLER_ARGS, uint32_t bit)
{
struct bcm_spi_softc *sc;
uint32_t reg;
int error;
sc = (struct bcm_spi_softc *)arg1;
BCM_SPI_LOCK(sc);
reg = BCM_SPI_READ(sc, SPI_CS);
BCM_SPI_UNLOCK(sc);
reg = (reg & bit) ? 1 : 0;
error = sysctl_handle_int(oidp, &reg, sizeof(reg), req);
if (error != 0 || req->newptr == NULL)
return (error);
return (0);
}
static int
bcm_spi_cpol_proc(SYSCTL_HANDLER_ARGS)
{
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CPOL));
}
static int
bcm_spi_cpha_proc(SYSCTL_HANDLER_ARGS)
{
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CPHA));
}
static int
bcm_spi_cspol0_proc(SYSCTL_HANDLER_ARGS)
{
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CSPOL0));
}
static int
bcm_spi_cspol1_proc(SYSCTL_HANDLER_ARGS)
{
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CSPOL1));
}
static int
bcm_spi_cspol2_proc(SYSCTL_HANDLER_ARGS)
{
return (bcm_spi_cs_bit_proc(oidp, arg1, arg2, req, SPI_CS_CSPOL2));
}
static void
bcm_spi_sysctl_init(struct bcm_spi_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, "clock",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_clock_proc, "IU", "SPI BUS clock frequency");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cpol",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cpol_proc, "IU", "SPI BUS clock polarity");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cpha",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cpha_proc, "IU", "SPI BUS clock phase");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol0",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cspol0_proc, "IU", "SPI BUS chip select 0 polarity");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol1",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cspol1_proc, "IU", "SPI BUS chip select 1 polarity");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "cspol2",
CTLFLAG_RD | CTLTYPE_UINT, sc, sizeof(*sc),
bcm_spi_cspol2_proc, "IU", "SPI BUS chip select 2 polarity");
}
static int
bcm_spi_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
return (ENXIO);
device_set_desc(dev, "BCM2708/2835 SPI controller");
return (BUS_PROBE_DEFAULT);
}
static int
bcm_spi_attach(device_t dev)
{
struct bcm_spi_softc *sc;
int rid;
if (device_get_unit(dev) != 0) {
device_printf(dev, "only one SPI controller supported\n");
return (ENXIO);
}
sc = device_get_softc(dev);
sc->sc_dev = dev;
rid = 0;
sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (!sc->sc_mem_res) {
device_printf(dev, "cannot allocate memory window\n");
return (ENXIO);
}
sc->sc_bst = rman_get_bustag(sc->sc_mem_res);
sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res);
rid = 0;
sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
RF_ACTIVE);
if (!sc->sc_irq_res) {
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
device_printf(dev, "cannot allocate interrupt\n");
return (ENXIO);
}
/* Hook up our interrupt handler. */
if (bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
NULL, bcm_spi_intr, sc, &sc->sc_intrhand)) {
bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
device_printf(dev, "cannot setup the interrupt handler\n");
return (ENXIO);
}
mtx_init(&sc->sc_mtx, "bcm_spi", NULL, MTX_DEF);
/* Add sysctl nodes. */
bcm_spi_sysctl_init(sc);
#ifdef BCM_SPI_DEBUG
bcm_spi_printr(dev);
#endif
/*
* Enable the SPI controller. Clear the rx and tx FIFO.
* Defaults to SPI mode 0.
*/
BCM_SPI_WRITE(sc, SPI_CS, SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO);
#ifdef BCM_SPI_DEBUG
bcm_spi_printr(dev);
#endif
device_add_child(dev, "spibus", -1);
return (bus_generic_attach(dev));
}
static int
bcm_spi_detach(device_t dev)
{
struct bcm_spi_softc *sc;
bus_generic_detach(dev);
sc = device_get_softc(dev);
mtx_destroy(&sc->sc_mtx);
if (sc->sc_intrhand)
bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand);
if (sc->sc_irq_res)
bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
if (sc->sc_mem_res)
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
return (0);
}
static void
bcm_spi_fill_fifo(struct bcm_spi_softc *sc)
{
struct spi_command *cmd;
uint32_t cs, written;
uint8_t *data;
cmd = sc->sc_cmd;
cs = BCM_SPI_READ(sc, SPI_CS) & (SPI_CS_TA | SPI_CS_TXD);
while (sc->sc_written < sc->sc_len &&
cs == (SPI_CS_TA | SPI_CS_TXD)) {
data = (uint8_t *)cmd->tx_cmd;
written = sc->sc_written++;
if (written >= cmd->tx_cmd_sz) {
data = (uint8_t *)cmd->tx_data;
written -= cmd->tx_cmd_sz;
}
BCM_SPI_WRITE(sc, SPI_FIFO, data[written]);
cs = BCM_SPI_READ(sc, SPI_CS) & (SPI_CS_TA | SPI_CS_TXD);
}
}
static void
bcm_spi_drain_fifo(struct bcm_spi_softc *sc)
{
struct spi_command *cmd;
uint32_t cs, read;
uint8_t *data;
cmd = sc->sc_cmd;
cs = BCM_SPI_READ(sc, SPI_CS) & SPI_CS_RXD;
while (sc->sc_read < sc->sc_len && cs == SPI_CS_RXD) {
data = (uint8_t *)cmd->rx_cmd;
read = sc->sc_read++;
if (read >= cmd->rx_cmd_sz) {
data = (uint8_t *)cmd->rx_data;
read -= cmd->rx_cmd_sz;
}
data[read] = BCM_SPI_READ(sc, SPI_FIFO) & 0xff;
cs = BCM_SPI_READ(sc, SPI_CS) & SPI_CS_RXD;
}
}
static void
bcm_spi_intr(void *arg)
{
struct bcm_spi_softc *sc;
sc = (struct bcm_spi_softc *)arg;
BCM_SPI_LOCK(sc);
/* Filter stray interrupts. */
if ((sc->sc_flags & BCM_SPI_BUSY) == 0) {
BCM_SPI_UNLOCK(sc);
return;
}
/* TX - Fill up the FIFO. */
bcm_spi_fill_fifo(sc);
/* RX - Drain the FIFO. */
bcm_spi_drain_fifo(sc);
/* Check for end of transfer. */
if (sc->sc_written == sc->sc_len && sc->sc_read == sc->sc_len) {
/* Disable interrupts and the SPI engine. */
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD, 0);
wakeup(sc->sc_dev);
}
BCM_SPI_UNLOCK(sc);
}
static int
bcm_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
{
struct bcm_spi_softc *sc;
uint32_t cs, mode, clock;
int err;
sc = device_get_softc(dev);
KASSERT(cmd->tx_cmd_sz == cmd->rx_cmd_sz,
("TX/RX command sizes should be equal"));
KASSERT(cmd->tx_data_sz == cmd->rx_data_sz,
("TX/RX data sizes should be equal"));
/* Get the bus speed, mode, and chip select for this child. */
spibus_get_cs(child, &cs);
if ((cs & (~SPIBUS_CS_HIGH)) > 2) {
device_printf(dev,
"Invalid chip select %u requested by %s\n", cs,
device_get_nameunit(child));
return (EINVAL);
}
spibus_get_clock(child, &clock);
if (clock == 0) {
device_printf(dev,
"Invalid clock %uHz requested by %s\n", clock,
device_get_nameunit(child));
return (EINVAL);
}
spibus_get_mode(child, &mode);
if (mode > 3) {
device_printf(dev,
"Invalid mode %u requested by %s\n", mode,
device_get_nameunit(child));
return (EINVAL);
}
/* If the controller is in use wait until it is available. */
BCM_SPI_LOCK(sc);
while (sc->sc_flags & BCM_SPI_BUSY)
mtx_sleep(dev, &sc->sc_mtx, 0, "bcm_spi", 0);
/* Now we have control over SPI controller. */
sc->sc_flags = BCM_SPI_BUSY;
/* Clear the FIFO. */
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO,
SPI_CS_CLEAR_RXFIFO | SPI_CS_CLEAR_TXFIFO);
/* Save a pointer to the SPI command. */
sc->sc_cmd = cmd;
sc->sc_read = 0;
sc->sc_written = 0;
sc->sc_len = cmd->tx_cmd_sz + cmd->tx_data_sz;
#ifdef BCM2835_SPI_USE_CS_HIGH /* TODO: for when behavior is correct */
/*
* Assign CS polarity first, while the CS indicates 'inactive'.
* This will need to set the correct polarity bit based on the 'cs', and
* the polarity bit will remain in this state, even after the transaction
* is complete.
*/
if((cs & ~SPIBUS_CS_HIGH) == 0) {
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_CSPOL0,
((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL0 : 0));
}
else if((cs & ~SPIBUS_CS_HIGH) == 1) {
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_CSPOL1,
((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL1 : 0));
}
else if((cs & ~SPIBUS_CS_HIGH) == 2) {
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_CSPOL2,
((cs & (SPIBUS_CS_HIGH)) ? SPI_CS_CSPOL2 : 0));
}
#endif
/*
* Set the mode in 'SPI_CS' (clock phase and polarity bits).
* This must happen before CS output pin is active.
* Otherwise, you might glitch and drop the first bit.
*/
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_CPOL | SPI_CS_CPHA,
((mode & SPIBUS_MODE_CPHA) ? SPI_CS_CPHA : 0) |
((mode & SPIBUS_MODE_CPOL) ? SPI_CS_CPOL : 0));
/*
* Set the clock divider in 'SPI_CLK - see 'bcm_spi_clock_proc()'.
*/
/* calculate 'clock' as a divider value from freq */
clock = SPI_CORE_CLK / clock;
if (clock <= 1)
clock = 2;
else if (clock % 2)
clock--;
if (clock > 0xffff)
clock = 0;
BCM_SPI_WRITE(sc, SPI_CLK, clock);
/*
* Set the CS for this transaction, enable interrupts and announce
* we're ready to tx. This will kick off the first interrupt.
*/
bcm_spi_modifyreg(sc, SPI_CS,
SPI_CS_MASK | SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD,
(cs & (~SPIBUS_CS_HIGH)) | /* cs is the lower 2 bits of the reg */
SPI_CS_TA | SPI_CS_INTR | SPI_CS_INTD);
/* Wait for the transaction to complete. */
err = mtx_sleep(dev, &sc->sc_mtx, 0, "bcm_spi", hz * 2);
/* 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);
/* Release the controller and wakeup the next thread waiting for it. */
sc->sc_flags = 0;
wakeup_one(dev);
BCM_SPI_UNLOCK(sc);
/*
* Check for transfer timeout. The SPI controller doesn't
* return errors.
*/
if (err == EWOULDBLOCK) {
device_printf(sc->sc_dev, "SPI error (timeout)\n");
err = EIO;
}
return (err);
}
static phandle_t
bcm_spi_get_node(device_t bus, device_t dev)
{
/* We only have one child, the SPI bus, which needs our own node. */
return (ofw_bus_get_node(bus));
}
static device_method_t bcm_spi_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, bcm_spi_probe),
DEVMETHOD(device_attach, bcm_spi_attach),
DEVMETHOD(device_detach, bcm_spi_detach),
/* SPI interface */
DEVMETHOD(spibus_transfer, bcm_spi_transfer),
/* ofw_bus interface */
DEVMETHOD(ofw_bus_get_node, bcm_spi_get_node),
DEVMETHOD_END
};
static devclass_t bcm_spi_devclass;
static driver_t bcm_spi_driver = {
"spi",
bcm_spi_methods,
sizeof(struct bcm_spi_softc),
};
DRIVER_MODULE(bcm2835_spi, simplebus, bcm_spi_driver, bcm_spi_devclass, 0, 0);