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// SPDX-License-Identifier: GPL-2.0
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/*
* Copyright ( C ) 2010 , 2015 Broadcom
* Copyright ( C ) 2013 - 2014 Lubomir Rintel
* Copyright ( C ) 2013 Craig McGeachie
*
* Parts of the driver are based on :
* - arch / arm / mach - bcm2708 / vcio . c file written by Gray Girling that was
* obtained from branch " rpi-3.6.y " of git : //github.com/raspberrypi/
* linux . git
* - drivers / mailbox / bcm2835 - ipc . c by Lubomir Rintel at
* https : //github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/
* mailbox / bcm2835 - ipc . c
* - documentation available on the following web site :
* https : //github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
*/
# include <linux/device.h>
# include <linux/dma-mapping.h>
# include <linux/err.h>
# include <linux/interrupt.h>
# include <linux/irq.h>
# include <linux/kernel.h>
# include <linux/mailbox_controller.h>
# include <linux/module.h>
# include <linux/of_address.h>
# include <linux/of_irq.h>
# include <linux/platform_device.h>
# include <linux/spinlock.h>
/* Mailboxes */
# define ARM_0_MAIL0 0x00
# define ARM_0_MAIL1 0x20
/*
* Mailbox registers . We basically only support mailbox 0 & 1. We
* deliver to the VC in mailbox 1 , it delivers to us in mailbox 0. See
* BCM2835 - ARM - Peripherals . pdf section 1.3 for an explanation about
* the placement of memory barriers .
*/
# define MAIL0_RD (ARM_0_MAIL0 + 0x00)
# define MAIL0_POL (ARM_0_MAIL0 + 0x10)
# define MAIL0_STA (ARM_0_MAIL0 + 0x18)
# define MAIL0_CNF (ARM_0_MAIL0 + 0x1C)
# define MAIL1_WRT (ARM_0_MAIL1 + 0x00)
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# define MAIL1_STA (ARM_0_MAIL1 + 0x18)
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/* Status register: FIFO state. */
# define ARM_MS_FULL BIT(31)
# define ARM_MS_EMPTY BIT(30)
/* Configuration register: Enable interrupts. */
# define ARM_MC_IHAVEDATAIRQEN BIT(0)
struct bcm2835_mbox {
void __iomem * regs ;
spinlock_t lock ;
struct mbox_controller controller ;
} ;
static struct bcm2835_mbox * bcm2835_link_mbox ( struct mbox_chan * link )
{
return container_of ( link - > mbox , struct bcm2835_mbox , controller ) ;
}
static irqreturn_t bcm2835_mbox_irq ( int irq , void * dev_id )
{
struct bcm2835_mbox * mbox = dev_id ;
struct device * dev = mbox - > controller . dev ;
struct mbox_chan * link = & mbox - > controller . chans [ 0 ] ;
while ( ! ( readl ( mbox - > regs + MAIL0_STA ) & ARM_MS_EMPTY ) ) {
u32 msg = readl ( mbox - > regs + MAIL0_RD ) ;
dev_dbg ( dev , " Reply 0x%08X \n " , msg ) ;
mbox_chan_received_data ( link , & msg ) ;
}
return IRQ_HANDLED ;
}
static int bcm2835_send_data ( struct mbox_chan * link , void * data )
{
struct bcm2835_mbox * mbox = bcm2835_link_mbox ( link ) ;
u32 msg = * ( u32 * ) data ;
spin_lock ( & mbox - > lock ) ;
writel ( msg , mbox - > regs + MAIL1_WRT ) ;
dev_dbg ( mbox - > controller . dev , " Request 0x%08X \n " , msg ) ;
spin_unlock ( & mbox - > lock ) ;
return 0 ;
}
static int bcm2835_startup ( struct mbox_chan * link )
{
struct bcm2835_mbox * mbox = bcm2835_link_mbox ( link ) ;
/* Enable the interrupt on data reception */
writel ( ARM_MC_IHAVEDATAIRQEN , mbox - > regs + MAIL0_CNF ) ;
return 0 ;
}
static void bcm2835_shutdown ( struct mbox_chan * link )
{
struct bcm2835_mbox * mbox = bcm2835_link_mbox ( link ) ;
writel ( 0 , mbox - > regs + MAIL0_CNF ) ;
}
static bool bcm2835_last_tx_done ( struct mbox_chan * link )
{
struct bcm2835_mbox * mbox = bcm2835_link_mbox ( link ) ;
bool ret ;
spin_lock ( & mbox - > lock ) ;
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ret = ! ( readl ( mbox - > regs + MAIL1_STA ) & ARM_MS_FULL ) ;
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spin_unlock ( & mbox - > lock ) ;
return ret ;
}
static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
. send_data = bcm2835_send_data ,
. startup = bcm2835_startup ,
. shutdown = bcm2835_shutdown ,
. last_tx_done = bcm2835_last_tx_done
} ;
static struct mbox_chan * bcm2835_mbox_index_xlate ( struct mbox_controller * mbox ,
const struct of_phandle_args * sp )
{
if ( sp - > args_count ! = 0 )
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return ERR_PTR ( - EINVAL ) ;
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return & mbox - > chans [ 0 ] ;
}
static int bcm2835_mbox_probe ( struct platform_device * pdev )
{
struct device * dev = & pdev - > dev ;
int ret = 0 ;
struct resource * iomem ;
struct bcm2835_mbox * mbox ;
mbox = devm_kzalloc ( dev , sizeof ( * mbox ) , GFP_KERNEL ) ;
if ( mbox = = NULL )
return - ENOMEM ;
spin_lock_init ( & mbox - > lock ) ;
ret = devm_request_irq ( dev , irq_of_parse_and_map ( dev - > of_node , 0 ) ,
bcm2835_mbox_irq , 0 , dev_name ( dev ) , mbox ) ;
if ( ret ) {
dev_err ( dev , " Failed to register a mailbox IRQ handler: %d \n " ,
ret ) ;
return - ENODEV ;
}
iomem = platform_get_resource ( pdev , IORESOURCE_MEM , 0 ) ;
mbox - > regs = devm_ioremap_resource ( & pdev - > dev , iomem ) ;
if ( IS_ERR ( mbox - > regs ) ) {
ret = PTR_ERR ( mbox - > regs ) ;
return ret ;
}
mbox - > controller . txdone_poll = true ;
mbox - > controller . txpoll_period = 5 ;
mbox - > controller . ops = & bcm2835_mbox_chan_ops ;
mbox - > controller . of_xlate = & bcm2835_mbox_index_xlate ;
mbox - > controller . dev = dev ;
mbox - > controller . num_chans = 1 ;
mbox - > controller . chans = devm_kzalloc ( dev ,
sizeof ( * mbox - > controller . chans ) , GFP_KERNEL ) ;
if ( ! mbox - > controller . chans )
return - ENOMEM ;
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ret = devm_mbox_controller_register ( dev , & mbox - > controller ) ;
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if ( ret )
return ret ;
platform_set_drvdata ( pdev , mbox ) ;
dev_info ( dev , " mailbox enabled \n " ) ;
return ret ;
}
static const struct of_device_id bcm2835_mbox_of_match [ ] = {
{ . compatible = " brcm,bcm2835-mbox " , } ,
{ } ,
} ;
MODULE_DEVICE_TABLE ( of , bcm2835_mbox_of_match ) ;
static struct platform_driver bcm2835_mbox_driver = {
. driver = {
. name = " bcm2835-mbox " ,
. of_match_table = bcm2835_mbox_of_match ,
} ,
. probe = bcm2835_mbox_probe ,
} ;
module_platform_driver ( bcm2835_mbox_driver ) ;
MODULE_AUTHOR ( " Lubomir Rintel <lkundrak@v3.sk> " ) ;
MODULE_DESCRIPTION ( " BCM2835 mailbox IPC driver " ) ;
MODULE_LICENSE ( " GPL v2 " ) ;