Re: [PATCH 4/4] drivers/mailbox: Add ASpeed mailbox driver

On Tue, 2017-02-07 at 16:10 +1030, Joel Stanley wrote:

On Thu, Jan 12, 2017 at 10:59 AM, Cyril Bur [off-list ref] wrote:

quoted

This provides access to the mbox registers on the ast2400 and ast2500
boards.

Hey Joel,

Thanks for review, just one thing, I'll fixup the rest.

Cyril

s/boards/SoCs/

quoted

This driver allows arbitrary reads and writes to the 16 data registers as
the other end may have configured the mbox hardware to provide an
interrupt when a specific register gets written to.

Signed-off-by: Cyril Bur <redacted>

Send this to lkml as well next time you submit.

quoted

---
 drivers/mailbox/Kconfig       |   9 ++
 drivers/mailbox/Makefile      |   2 +
 drivers/mailbox/aspeed-mbox.c | 334 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 345 insertions(+)
 create mode 100644 drivers/mailbox/aspeed-mbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index ceff415f201c..10a7f3f2765c 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig

@@ -152,4 +152,13 @@ config BCM_PDC_MBOX
          Mailbox implementation for the Broadcom PDC ring manager,
          which provides access to various offload engines on Broadcom
          SoCs. Say Y here if you want to use the Broadcom PDC.
+
+config ASPEED_MBOX

Call this ASPEED_LPC_MAILBOX, as it's a in the LPC IP block.

I think I'll stick with ASPEED_LPC_MBOX, the rest of the file uses MBOX
more widely when talking about controllers.

quoted

+       depends on (ARCH_ASPEED || COMPILE_TEST) && REGMAP && MFD_SYSCON
+       bool "Aspeed ast2400/2500 Mailbox Controller"

Call this Aspeed LPC Mailbox Controller, as the layout is shared by
SoCs other than the 2500 and 2400.

quoted

+       default "y"
+       ---help---
+         Provides a driver for the MBOX registers found on Aspeed SOCs
+         (AST2400 and AST2500). This driver provides a device for aspeed
+         mbox registers
 endif

diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 7dde4f609ae8..db5b4f3f29e0 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile

@@ -31,3 +31,5 @@ obj-$(CONFIG_HI6220_MBOX)     += hi6220-mailbox.o
 obj-$(CONFIG_BCM_PDC_MBOX)     += bcm-pdc-mailbox.o

 obj-$(CONFIG_TEGRA_HSP_MBOX)   += tegra-hsp.o
+
+obj-$(CONFIG_ASPEED_MBOX)      += aspeed-mbox.o

diff --git a/drivers/mailbox/aspeed-mbox.c b/drivers/mailbox/aspeed-mbox.c
new file mode 100644
index 000000000000..c4ee6ba228ea
--- /dev/null
+++ b/drivers/mailbox/aspeed-mbox.c
+
+static ssize_t aspeed_mbox_read(struct file *file, char __user *buf,
+                               size_t count, loff_t *ppos)
+{
+       struct aspeed_mbox *mbox = file_mbox(file);
+       char __user *p = buf;
+       ssize_t ret;
+       int i;
+
+       if (!access_ok(VERIFY_WRITE, buf, count))
+               return -EFAULT;

As discussed in the LPC driver review:

 "And don't call access_ok(), it's racy and no driver should ever do that."

Make sure all of the things you fixed in that driver are fixed in this one.

quoted

+
+       if (count + *ppos > ASPEED_MBOX_NUM_REGS)
+               return -EINVAL;
+
+       if (file->f_flags & O_NONBLOCK) {
+               if (!(aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) &
+                               ASPEED_MBOX_CTRL_RECV))
+                       return -EAGAIN;
+       } else if (wait_event_interruptible(mbox->queue,
+                               aspeed_mbox_inb(mbox, ASPEED_MBOX_BMC_CTRL) &
+                               ASPEED_MBOX_CTRL_RECV)) {
+               return -ERESTARTSYS;
+       }
+
+       mutex_lock(&mbox->mutex);
+
+       for (i = *ppos; count > 0 && i < ASPEED_MBOX_NUM_REGS; i++) {
+               uint8_t reg = aspeed_mbox_inb(mbox, ASPEED_MBOX_DATA_0 + (i * 4));
+
+               ret = __put_user(reg, p);
+               if (ret)
+                       goto out_unlock;
+
+               p++;
+               count--;
+       }
+
+       /* ASPEED_MBOX_CTRL_RECV bit is W1C, this also unmasks in 1 step */

W1C? Write to clear?

quoted

+       aspeed_mbox_outb(mbox, ASPEED_MBOX_CTRL_RECV, ASPEED_MBOX_BMC_CTRL);
+       ret = p - buf;
+
+out_unlock:
+       mutex_unlock(&mbox->mutex);
+       return ret;
+}
+
+module_platform_driver(aspeed_mbox_driver);
+
+MODULE_DEVICE_TABLE(of, aspeed_mbox_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cyril Bur [off-list ref]");
+MODULE_DESCRIPTION("ASpeed mailbox device driver");

ASPEED or Aspeed.

quoted

--
2.11.0

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