Re: [PATCH v3 5/6] bus: Add Baikal-T1 APB-bus driver

From: Arnd Bergmann
Date: Thu May 28 2020 - 08:17:42 EST


On Tue, May 26, 2020 at 2:59 PM Serge Semin
<Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Baikal-T1 AXI-APB bridge is used to access the SoC subsystem CSRs.
> IO requests are routed to this bus by means of the DW AMBA 3 AXI
> Interconnect. In case if an attempted APB transaction stays with no
> response for a pre-defined time an interrupt occurs and the bus gets
> freed for a next operation. This driver provides the interrupt handler
> to detect the erroneous address, prints an error message about the
> address fault, updates an errors counter. The counter and the APB-bus
> operations timeout can be accessed via corresponding sysfs nodes.
> A dedicated sysfs-node can be also used to artificially cause the
> bus errors described above.
>
> Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> Cc: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx>
> Cc: Paul Burton <paulburton@xxxxxxxxxx>
> Cc: Olof Johansson <olof@xxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: linux-mips@xxxxxxxxxxxxxxx
> Cc: soc@xxxxxxxxxx
> Cc: devicetree@xxxxxxxxxxxxxxx
>
> ---

Applied with this fixup:

--- a/drivers/bus/bt1-apb.c
+++ b/drivers/bus/bt1-apb.c
@@ -16,6 +16,7 @@
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/nmi.h>
+#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/clk.h>
#include <linux/reset.h>
@@ -309,13 +310,13 @@ static ssize_t timeout_store(struct device *dev,
}
static DEVICE_ATTR_RW(timeout);

-static int inject_error_show(struct device *dev, struct device_attribute *attr,
+static ssize_t inject_error_show(struct device *dev, struct
device_attribute *attr,
char *buf)
{
return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n");
}

-static int inject_error_store(struct device *dev,
+static ssize_t inject_error_store(struct device *dev,
struct device_attribute *attr,
const char *data, size_t count)
{