pl320-ipc.c
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/*
* 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/pl320-ipc.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_GPL(pl320_ipc_transmit);
static 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_GPL(pl320_ipc_register_notifier);
int pl320_ipc_unregister_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&ipc_notifier, nb);
}
EXPORT_SYMBOL_GPL(pl320_ipc_unregister_notifier);
static int 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);
}
subsys_initcall(ipc_init);