Re: [PATCH v3 03/11] stm class: dummy_stm: Add dummy driver for testing stm class

From: Mathieu Poirier
Date: Wed Aug 05 2015 - 19:02:35 EST


On 6 July 2015 at 04:08, Alexander Shishkin
<alexander.shishkin@xxxxxxxxxxxxxxx> wrote:
> This is a simple module that pretends to be an stm device and discards
> all the data that comes in. Useful for testing stm class and its users.
>
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> ---
> drivers/hwtracing/stm/Kconfig | 8 +++++
> drivers/hwtracing/stm/Makefile | 2 ++
> drivers/hwtracing/stm/dummy_stm.c | 66 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 76 insertions(+)
> create mode 100644 drivers/hwtracing/stm/dummy_stm.c
>
> diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
> index 90ed327461..4fdb8f46d2 100644
> --- a/drivers/hwtracing/stm/Kconfig
> +++ b/drivers/hwtracing/stm/Kconfig
> @@ -6,3 +6,11 @@ config STM
> Examples of such devices are Intel Trace Hub and Coresight STM.
>
> Say Y here to enable System Trace Module device support.
> +
> +config STM_DUMMY
> + tristate "Dummy STM driver"
> + help
> + This is a simple dummy device that pretends to be an stm device
> + and discards your data. Use for stm class testing.
> +
> + If you don't know what this is, say N.
> diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
> index adec701649..1b2725fd04 100644
> --- a/drivers/hwtracing/stm/Makefile
> +++ b/drivers/hwtracing/stm/Makefile
> @@ -1,3 +1,5 @@
> obj-$(CONFIG_STM) += stm_core.o
>
> stm_core-y := core.o policy.o
> +
> +obj-$(CONFIG_STM_DUMMY) += dummy_stm.o
> diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
> new file mode 100644
> index 0000000000..3709bef0b2
> --- /dev/null
> +++ b/drivers/hwtracing/stm/dummy_stm.c
> @@ -0,0 +1,66 @@
> +/*
> + * A dummy STM device for stm/stm_source class testing.
> + * Copyright (c) 2014, Intel Corporation.
> + *
> + * 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.
> + *
> + * STM class implements generic infrastructure for System Trace Module devices
> + * as defined in MIPI STPv2 specification.
> + */
> +
> +#undef DEBUG
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/stm.h>
> +
> +static ssize_t
> +dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
> + unsigned int channel, unsigned int packet, unsigned int flags,
> + unsigned int size, const unsigned char *payload)
> +{
> +#ifdef DEBUG
> + u64 pl = 0;
> +
> + if (payload)
> + pl = *(u64 *)payload;
> +
> + if (size < 8)
> + pl &= (1ull << (size * 8)) - 1;
> + trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,
> + packet, size, pl);
> +#endif
> + return size;
> +}
> +
> +static struct stm_data dummy_stm = {
> + .name = "dummy_stm",
> + .sw_start = 0x0000,
> + .sw_end = 0xffff,
> + .sw_nchannels = 0xffff,
> + .packet = dummy_stm_packet,
> +};
> +
> +static int dummy_stm_init(void)
> +{
> + return stm_register_device(NULL, &dummy_stm, THIS_MODULE);
> +}
> +
> +static void dummy_stm_exit(void)
> +{
> + stm_unregister_device(&dummy_stm);
> +}
> +
> +module_init(dummy_stm_init);
> +module_exit(dummy_stm_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("dummy_stm device");
> +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>");
> --
> 2.1.4
>

Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
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