On 8/28/19 10:05 AM, Michael Ellerman wrote:
> From: Claudio Carvalho <cclau...@linux.ibm.com>
>
> The ultravisor (UV) provides an in-memory console which follows the
> OPAL in-memory console structure.
>
> This patch extends the OPAL msglog code to initialize the UV memory
> console and provide the "/sys/firmware/ultravisor/msglog" interface
> for userspace to view the UV message log.
Tested-by: Claudio Carvalho <cclau...@linux.ibm.com>
Thanks,
Claudio
>
> Signed-off-by: Claudio Carvalho <cclau...@linux.ibm.com>
> Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
> ---
> v4: mpe: Move all the code into ultravisor.c.
> Consistently use "uv_" as the prefix not "ultra_".
> Use powernv.h for routines that are shared within the platform.
> Rather than bloating the kernel with strings for every rare error
> case, return error codes from the init routine which can be
> seen with initcall_debug.
> ---
> arch/powerpc/platforms/powernv/powernv.h | 5 +++
> arch/powerpc/platforms/powernv/ultravisor.c | 45 +++++++++++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/arch/powerpc/platforms/powernv/powernv.h
> b/arch/powerpc/platforms/powernv/powernv.h
> index fd4a1c5a6369..1aa51c4fa904 100644
> --- a/arch/powerpc/platforms/powernv/powernv.h
> +++ b/arch/powerpc/platforms/powernv/powernv.h
> @@ -30,4 +30,9 @@ extern void opal_event_shutdown(void);
>
> bool cpu_core_split_required(void);
>
> +struct memcons;
> +ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
> +u32 memcons_get_size(struct memcons *mc);
> +struct memcons *memcons_init(struct device_node *node, const char
> *mc_prop_name);
> +
> #endif /* _POWERNV_H */
> diff --git a/arch/powerpc/platforms/powernv/ultravisor.c
> b/arch/powerpc/platforms/powernv/ultravisor.c
> index 02ac57b4bded..e4a00ad06f9d 100644
> --- a/arch/powerpc/platforms/powernv/ultravisor.c
> +++ b/arch/powerpc/platforms/powernv/ultravisor.c
> @@ -8,9 +8,15 @@
> #include <linux/init.h>
> #include <linux/printk.h>
> #include <linux/of_fdt.h>
> +#include <linux/of.h>
>
> #include <asm/ultravisor.h>
> #include <asm/firmware.h>
> +#include <asm/machdep.h>
> +
> +#include "powernv.h"
> +
> +static struct kobject *ultravisor_kobj;
>
> int __init early_init_dt_scan_ultravisor(unsigned long node, const char
> *uname,
> int depth, void *data)
> @@ -22,3 +28,42 @@ int __init early_init_dt_scan_ultravisor(unsigned long
> node, const char *uname,
> pr_debug("Ultravisor detected!\n");
> return 1;
> }
> +
> +static struct memcons *uv_memcons;
> +
> +static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
> + struct bin_attribute *bin_attr, char *to,
> + loff_t pos, size_t count)
> +{
> + return memcons_copy(uv_memcons, to, pos, count);
> +}
> +
> +static struct bin_attribute uv_msglog_attr = {
> + .attr = {.name = "msglog", .mode = 0400},
> + .read = uv_msglog_read
> +};
> +
> +static int __init uv_init(void)
> +{
> + struct device_node *node;
> +
> + if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
> + return 0;
> +
> + node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
> + if (!node)
> + return -ENODEV;
> +
> + uv_memcons = memcons_init(node, "memcons");
> + if (!uv_memcons)
> + return -ENOENT;
> +
> + uv_msglog_attr.size = memcons_get_size(uv_memcons);
> +
> + ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
> + if (!ultravisor_kobj)
> + return -ENOMEM;
> +
> + return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
> +}
> +machine_subsys_initcall(powernv, uv_init);
