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    Subject[PATCH 4/6 v8] arm highbank: add support for pl320 IPC
    Date
    From: Rob Herring <rob.herring@calxeda.com>

    The pl320 IPC allows for interprocessor communication between the highbank A9
    and the EnergyCore Management Engine. The pl320 implements a straightforward
    mailbox protocol.

    This patch depends on Omar Ramirez Luna's <omar.luna@linaro.org>
    mailbox driver patch series.

    Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
    Signed-off-by: Rob Herring <rob.herring@calxeda.com>
    Cc: Omar Ramirez Luna <omar.luna@linaro.org>
    Cc: Arnd Bergmann <arnd@arndb.de>
    ---
    Changes from v6, v7
    None.
    Changes from v5
    Renamed ipc_transmit() to pl320_ipc_transmit().
    Properly exported pl320_ipc_{un}register_notifier().
    Changes from v4
    Moved pl320-ipc.c from arch/arm/mach-highbank to drivers/mailbox.
    Moved header information to include/linux/mailbox.h.
    Added Kconfig options to reflect the new code location.
    Change drivers/mailbox/Makefile to build the omap mailboxes only
    when they are configured.
    Removed ipc_call_fast and renamed ipc_call_slow ipc_transmit.
    Changes from v3, v2
    None.
    Changes from v1
    Removed erroneous changes for cpufreq Kconfig.

    arch/arm/mach-highbank/Kconfig | 2 +
    drivers/mailbox/Kconfig | 9 ++
    drivers/mailbox/Makefile | 4 +
    drivers/mailbox/pl320-ipc.c | 199 +++++++++++++++++++++++++++++++++++++++++
    include/linux/mailbox.h | 19 +++-
    5 files changed, 232 insertions(+), 1 deletion(-)
    create mode 100644 drivers/mailbox/Makefile
    create mode 100644 drivers/mailbox/pl320-ipc.c

    diff --git a/arch/arm/mach-highbank/Kconfig b/arch/arm/mach-highbank/Kconfig
    index 0e1d0a4..2896881 100644
    --- a/arch/arm/mach-highbank/Kconfig
    +++ b/arch/arm/mach-highbank/Kconfig
    @@ -11,5 +11,7 @@ config ARCH_HIGHBANK
    select GENERIC_CLOCKEVENTS
    select HAVE_ARM_SCU
    select HAVE_SMP
    + select MAILBOX
    + select PL320_MBOX
    select SPARSE_IRQ
    select USE_OF
    diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
    index be8cac0..e89fdb4 100644
    --- a/drivers/mailbox/Kconfig
    +++ b/drivers/mailbox/Kconfig
    @@ -34,4 +34,13 @@ config OMAP_MBOX_KFIFO_SIZE
    This can also be changed at runtime (via the mbox_kfifo_size
    module parameter).

    +config PL320_MBOX
    + bool "ARM PL320 Mailbox"
    + help
    + An implementation of the ARM PL320 Interprocessor Communication
    + Mailbox (IPCM), tailored for the Calxeda Highbank. It is used to
    + send short messages between Highbank's A9 cores and the EnergyCore
    + Management Engine, primarily for cpufreq. Say Y here if you want
    + to use the PL320 IPCM support.
    +
    endif
    diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
    new file mode 100644
    index 0000000..c9f14c3
    --- /dev/null
    +++ b/drivers/mailbox/Makefile
    @@ -0,0 +1,4 @@
    +obj-$(CONFIG_OMAP1_MBOX) += mailbox.o mailbox-omap1.o
    +obj-$(CONFIG_OMAP2PLUS_MBOX) += mailbox.o mailbox-omap2.o
    +obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o
    +
    diff --git a/drivers/mailbox/pl320-ipc.c b/drivers/mailbox/pl320-ipc.c
    new file mode 100644
    index 0000000..1a9d8e4
    --- /dev/null
    +++ b/drivers/mailbox/pl320-ipc.c
    @@ -0,0 +1,199 @@
    +/*
    + * Copyright 2012 Calxeda, Inc.
    + *
    + * This program is free software; you can redistribute it and/or modify it
    + * under the terms and conditions of the GNU General Public License,
    + * version 2, as published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope it will be useful, but WITHOUT
    + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    + * more details.
    + *
    + * You should have received a copy of the GNU General Public License along with
    + * this program. If not, see <http://www.gnu.org/licenses/>.
    + */
    +#include <linux/types.h>
    +#include <linux/err.h>
    +#include <linux/delay.h>
    +#include <linux/export.h>
    +#include <linux/io.h>
    +#include <linux/interrupt.h>
    +#include <linux/completion.h>
    +#include <linux/mutex.h>
    +#include <linux/notifier.h>
    +#include <linux/spinlock.h>
    +#include <linux/device.h>
    +#include <linux/amba/bus.h>
    +
    +#include <linux/mailbox.h>
    +
    +#define IPCMxSOURCE(m) ((m) * 0x40)
    +#define IPCMxDSET(m) (((m) * 0x40) + 0x004)
    +#define IPCMxDCLEAR(m) (((m) * 0x40) + 0x008)
    +#define IPCMxDSTATUS(m) (((m) * 0x40) + 0x00C)
    +#define IPCMxMODE(m) (((m) * 0x40) + 0x010)
    +#define IPCMxMSET(m) (((m) * 0x40) + 0x014)
    +#define IPCMxMCLEAR(m) (((m) * 0x40) + 0x018)
    +#define IPCMxMSTATUS(m) (((m) * 0x40) + 0x01C)
    +#define IPCMxSEND(m) (((m) * 0x40) + 0x020)
    +#define IPCMxDR(m, dr) (((m) * 0x40) + ((dr) * 4) + 0x024)
    +
    +#define IPCMMIS(irq) (((irq) * 8) + 0x800)
    +#define IPCMRIS(irq) (((irq) * 8) + 0x804)
    +
    +#define MBOX_MASK(n) (1 << (n))
    +#define IPC_TX_MBOX 1
    +#define IPC_RX_MBOX 2
    +
    +#define CHAN_MASK(n) (1 << (n))
    +#define A9_SOURCE 1
    +#define M3_SOURCE 0
    +
    +static void __iomem *ipc_base;
    +static int ipc_irq;
    +static DEFINE_MUTEX(ipc_m1_lock);
    +static DECLARE_COMPLETION(ipc_completion);
    +static ATOMIC_NOTIFIER_HEAD(ipc_notifier);
    +
    +static inline void set_destination(int source, int mbox)
    +{
    + __raw_writel(CHAN_MASK(source), ipc_base + IPCMxDSET(mbox));
    + __raw_writel(CHAN_MASK(source), ipc_base + IPCMxMSET(mbox));
    +}
    +
    +static inline void clear_destination(int source, int mbox)
    +{
    + __raw_writel(CHAN_MASK(source), ipc_base + IPCMxDCLEAR(mbox));
    + __raw_writel(CHAN_MASK(source), ipc_base + IPCMxMCLEAR(mbox));
    +}
    +
    +static void __ipc_send(int mbox, u32 *data)
    +{
    + int i;
    + for (i = 0; i < 7; i++)
    + __raw_writel(data[i], ipc_base + IPCMxDR(mbox, i));
    + __raw_writel(0x1, ipc_base + IPCMxSEND(mbox));
    +}
    +
    +static u32 __ipc_rcv(int mbox, u32 *data)
    +{
    + int i;
    + for (i = 0; i < 7; i++)
    + data[i] = __raw_readl(ipc_base + IPCMxDR(mbox, i));
    + return data[1];
    +}
    +
    +/* blocking implmentation from the A9 side, not usuable in interrupts! */
    +int pl320_ipc_transmit(u32 *data)
    +{
    + int ret;
    +
    + mutex_lock(&ipc_m1_lock);
    +
    + init_completion(&ipc_completion);
    + __ipc_send(IPC_TX_MBOX, data);
    + ret = wait_for_completion_timeout(&ipc_completion,
    + msecs_to_jiffies(1000));
    + if (ret == 0) {
    + ret = -ETIMEDOUT;
    + goto out;
    + }
    +
    + ret = __ipc_rcv(IPC_TX_MBOX, data);
    +out:
    + mutex_unlock(&ipc_m1_lock);
    + return ret;
    +}
    +EXPORT_SYMBOL(pl320_ipc_transmit);
    +
    +irqreturn_t ipc_handler(int irq, void *dev)
    +{
    + u32 irq_stat;
    + u32 data[7];
    +
    + irq_stat = __raw_readl(ipc_base + IPCMMIS(1));
    + if (irq_stat & MBOX_MASK(IPC_TX_MBOX)) {
    + __raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
    + complete(&ipc_completion);
    + }
    + if (irq_stat & MBOX_MASK(IPC_RX_MBOX)) {
    + __ipc_rcv(IPC_RX_MBOX, data);
    + atomic_notifier_call_chain(&ipc_notifier, data[0], data + 1);
    + __raw_writel(2, ipc_base + IPCMxSEND(IPC_RX_MBOX));
    + }
    +
    + return IRQ_HANDLED;
    +}
    +
    +int pl320_ipc_register_notifier(struct notifier_block *nb)
    +{
    + return atomic_notifier_chain_register(&ipc_notifier, nb);
    +}
    +EXPORT_SYMBOL(pl320_ipc_register_notifier);
    +
    +int pl320_ipc_unregister_notifier(struct notifier_block *nb)
    +{
    + return atomic_notifier_chain_unregister(&ipc_notifier, nb);
    +}
    +EXPORT_SYMBOL(pl320_ipc_unregister_notifier);
    +
    +static int __devinit pl320_probe(struct amba_device *adev,
    + const struct amba_id *id)
    +{
    + int ret;
    +
    + ipc_base = ioremap(adev->res.start, resource_size(&adev->res));
    + if (ipc_base == NULL)
    + return -ENOMEM;
    +
    + __raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
    +
    + ipc_irq = adev->irq[0];
    + ret = request_irq(ipc_irq, ipc_handler, 0, dev_name(&adev->dev), NULL);
    + if (ret < 0)
    + goto err;
    +
    + /* Init slow mailbox */
    + __raw_writel(CHAN_MASK(A9_SOURCE),
    + ipc_base + IPCMxSOURCE(IPC_TX_MBOX));
    + __raw_writel(CHAN_MASK(M3_SOURCE),
    + ipc_base + IPCMxDSET(IPC_TX_MBOX));
    + __raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
    + ipc_base + IPCMxMSET(IPC_TX_MBOX));
    +
    + /* Init receive mailbox */
    + __raw_writel(CHAN_MASK(M3_SOURCE),
    + ipc_base + IPCMxSOURCE(IPC_RX_MBOX));
    + __raw_writel(CHAN_MASK(A9_SOURCE),
    + ipc_base + IPCMxDSET(IPC_RX_MBOX));
    + __raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
    + ipc_base + IPCMxMSET(IPC_RX_MBOX));
    +
    + return 0;
    +err:
    + iounmap(ipc_base);
    + return ret;
    +}
    +
    +static struct amba_id pl320_ids[] = {
    + {
    + .id = 0x00041320,
    + .mask = 0x000fffff,
    + },
    + { 0, 0 },
    +};
    +
    +static struct amba_driver pl320_driver = {
    + .drv = {
    + .name = "pl320",
    + },
    + .id_table = pl320_ids,
    + .probe = pl320_probe,
    +};
    +
    +static int __init ipc_init(void)
    +{
    + return amba_driver_register(&pl320_driver);
    +}
    +module_init(ipc_init);
    diff --git a/include/linux/mailbox.h b/include/linux/mailbox.h
    index e8e4131..e7829e5 100644
    --- a/include/linux/mailbox.h
    +++ b/include/linux/mailbox.h
    @@ -1,4 +1,16 @@
    -/* mailbox.h */
    +/*
    + * This program is free software; you can redistribute it and/or modify it
    + * under the terms and conditions of the GNU General Public License,
    + * version 2, as published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope it will be useful, but WITHOUT
    + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    + * more details.
    + *
    + * You should have received a copy of the GNU General Public License along with
    + * this program. If not, see <http://www.gnu.org/licenses/>.
    + */

    typedef u32 mbox_msg_t;
    struct omap_mbox;
    @@ -20,3 +32,8 @@ void omap_mbox_save_ctx(struct omap_mbox *mbox);
    void omap_mbox_restore_ctx(struct omap_mbox *mbox);
    void omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq);
    void omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq);
    +
    +int pl320_ipc_transmit(u32 *data);
    +int pl320_ipc_register_notifier(struct notifier_block *nb);
    +int pl320_ipc_unregister_notifier(struct notifier_block *nb);
    +
    --
    1.7.11.7


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