Re: [PATCH 3/3] mailbox: sophgo: add mailbox driver for cv18x SoCs

[Yuntao Dai]

Hi Junhui,

On Tue, Jul 2, 2024 at 11:08 PM, Junhui Liu <liujh2818@xxxxxxxxx> wrote:
> Hi Yuntao,
>
> On 2024/6/18 23:12, Yuntao Dai wrote:
> > Add mailbox controller driver for cv18x SoCs, tested on mailbox-test
> > client.
> >
> > Signed-off-by: Yuntao Dai <d1581209858@xxxxxxxx>
> > ---
> >   drivers/mailbox/Kconfig           |  11 ++
> >   drivers/mailbox/Makefile          |   2 +
> >   drivers/mailbox/cv1800b-mailbox.c | 181 
> > ++++++++++++++++++++++++++++++
> >   3 files changed, 194 insertions(+)
> >   create mode 100644 drivers/mailbox/cv1800b-mailbox.c
> >
> > diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> > index 3b8842c4a..4e5593861 100644
> > --- a/drivers/mailbox/Kconfig
> > +++ b/drivers/mailbox/Kconfig
> > @@ -286,4 +286,15 @@ config QCOM_IPCC
> >   	  acts as an interrupt controller for receiving interrupts from 
> > clients.
> >   	  Say Y here if you want to build this driver.
> >   +config CV1800B_MBOX
> > +	tristate "cv1800b mailbox"
> > +	depends on OF
> > +	depends on ARCH_SOPHGO || COMPILE_TEST
> > +	help
> > +	  Mailbox driver implementation for Sophgo cv180x SoCs. This driver
> > +	  can be used to send message between different processors in SoC. 
> > Any
> > +	  processer can write data in a channel, and set co-responding 
> > register
> > +	  to raise interrupt to notice another processor, and it is 
> > allowed to
> > +	  send data to itself.
> > +
> >   endif
> > diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> > index 5cf2f54de..71f0f746e 100644
> > --- a/drivers/mailbox/Makefile
> > +++ b/drivers/mailbox/Makefile
> > @@ -62,3 +62,5 @@ obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
> >   obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
> >   better
> >   obj-$(CONFIG_QCOM_IPCC)		+= qcom-ipcc.o
> > +
> > +obj-$(CONFIG_CV1800B_MBOX)	+= cv1800b-mailbox.o
> > \ No newline at end of file
> > diff --git a/drivers/mailbox/cv1800b-mailbox.c 
> > b/drivers/mailbox/cv1800b-mailbox.c
> > new file mode 100644
> > index 000000000..8ef2a5492
> > --- /dev/null
> > +++ b/drivers/mailbox/cv1800b-mailbox.c
> > @@ -0,0 +1,181 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +
> > +#include <linux/device.h>
> > +#include <linux/err.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/kfifo.h>
> > +#include <linux/mailbox_controller.h>
> > +#include <linux/mailbox_client.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +#define MAILBOX_MAX_CHAN 0x0008
> > +#define MAILBOX_DONE_OFFSET 0x0002
> > +#define MAILBOX_CONTEXT_SIZE 0x0040
> > +#define MAILBOX_CONTEXT_OFFSET 0x0400
> > +
> > +#define MBOX_EN_REG(cpu) (cpu << 2)
> > +#define MBOX_DONE_REG(cpu) ((cpu << 2) + MAILBOX_DONE_OFFSET)
> > +
> > +#define MBOX_SET_CLR_REG(cpu) (0x10 + (cpu << 4))
> > +#define MBOX_SET_INT_REG(cpu) (0x18 + (cpu << 4))
> > +
> > +#define MBOX_SET_REG 0x60
> > +
> > +struct cv1800b_mbox {
> > +	struct mbox_controller mbox;
> > +	struct mbox_chan chans[MAILBOX_MAX_CHAN];
> > +	u64 *content[MAILBOX_MAX_CHAN];
> > +	void __iomem *mbox_base;
> > +	int sendto;
> > +	int recvid;
> > +};
> > +
> > +static irqreturn_t cv1800b_mbox_isr(int irq, void *dev_id)
> > +{
> > +	struct cv1800b_mbox *mbox = (struct cv1800b_mbox *)dev_id;
> > +	size_t i;
> > +
> > +	for (i = 0; i < MAILBOX_MAX_CHAN; i++) {
> > +		if (mbox->content[i]) {
> > +			mbox_chan_received_data(&mbox->chans[i],
> > +						mbox->content[i]);
> I tested this driver but met "NULL pointer dereference" Oops here
> when I sent message from the c906l core without binding clients.
>
> I think maybe it's better to add a check here, like:
>
> struct mbox_chan *chan = &mbox->chans[i];
> if (chan->cl) {
>     mbox_chan_received_data(chan, mbox->content[i]);
> }
>
> Best,
> Junhui Liu

Thanks for your addvice, I will take it. On the other side, I am not 
sure weather mailbox driver can work without register mailbox client 
correctly?

Best regards,
Yuntao