cregit-Linux how code gets into the kernel

Release 4.7 drivers/mailbox/pl320-ipc.c

Directory: drivers/mailbox
/*
 * 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)); }

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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)); }

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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)); }

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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]; }

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/* 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; }

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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; }

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int pl320_ipc_register_notifier(struct notifier_block *nb) { return atomic_notifier_chain_register(&ipc_notifier, nb); }

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EXPORT_SYMBOL_GPL(pl320_ipc_register_notifier);
int pl320_ipc_unregister_notifier(struct notifier_block *nb) { return atomic_notifier_chain_unregister(&ipc_notifier, nb); }

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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; }

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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); }

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subsys_initcall(ipc_init);

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Directory: drivers/mailbox
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