On 22-11-20, 23:21, Bjorn Andersson wrote:
> Every now and then it's convenient to be able to inspect the content of
> SMEM items. Rather than carrying some hack locally let's upstream a
> driver that when inserted exposes a debugfs interface for dumping
> available items.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
> drivers/soc/qcom/Kconfig | 7 +++
> drivers/soc/qcom/Makefile | 1 +
> drivers/soc/qcom/smem_debugfs.c | 102 ++++++++++++++++++++++++++++++++
> 3 files changed, 110 insertions(+)
> create mode 100644 drivers/soc/qcom/smem_debugfs.c
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 3dc3e3d61ea3..7e1dd6b3f33a 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -128,6 +128,13 @@ config QCOM_SMEM
> The driver provides an interface to items in a heap shared among all
> processors in a Qualcomm platform.
>
> +config QCOM_SMEM_DEBUGFS
> + tristate "Qualcomm Shared Memory Manager (SMEM) DebugFS interface"
> + depends on QCOM_SMEM
> + depends on DEBUG_FS
> + help
> + Provides a debugfs interface for inspecting SMEM.
Do we need additional debugfs entry, maybe better to depend on DEBUG_FS
being enabled and this file part of QCOM_SMEM?
> +
> config QCOM_SMD_RPM
> tristate "Qualcomm Resource Power Manager (RPM) over SMD"
> depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index 93392d9dc7f7..632eefc5a897 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -15,6 +15,7 @@ qcom_rpmh-y += rpmh-rsc.o
> qcom_rpmh-y += rpmh.o
> obj-$(CONFIG_QCOM_SMD_RPM) += smd-rpm.o
> obj-$(CONFIG_QCOM_SMEM) += smem.o
> +obj-$(CONFIG_QCOM_SMEM_DEBUGFS) += smem_debugfs.o
> obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
> obj-$(CONFIG_QCOM_SMP2P) += smp2p.o
> obj-$(CONFIG_QCOM_SMSM) += smsm.o
> diff --git a/drivers/soc/qcom/smem_debugfs.c b/drivers/soc/qcom/smem_debugfs.c
> new file mode 100644
> index 000000000000..11ef29a0cada
> --- /dev/null
> +++ b/drivers/soc/qcom/smem_debugfs.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020, Linaro Ltd.
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/soc/qcom/smem.h>
> +
> +struct smem_debugfs {
> + struct dentry *root;
> +};
> +
> +static int smem_debugfs_item_show(struct seq_file *seq, void *p)
> +{
> + unsigned long data = (unsigned long)seq->private;
> + unsigned long item = data & 0xffff;
> + unsigned long host = data >> 16;
> + size_t len;
> + void *ptr;
> +
> + ptr = qcom_smem_get(host, item, &len);
> + if (IS_ERR(ptr))
> + return PTR_ERR(ptr);
> +
> + seq_hex_dump(seq, "", DUMP_PREFIX_OFFSET, 16, 1, ptr, len, true);
> +
> + return 0;
> +}
> +
> +static int smem_debugfs_item_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, smem_debugfs_item_show, inode->i_private);
> +}
> +
> +static const struct file_operations smem_debugfs_item_ops = {
> + .open = smem_debugfs_item_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
How about using DEFINE_SHOW_ATTRIBUTE() instead? That will help cut down
this boiler plate code..
> +
> +static int smem_debugfs_rescan(struct seq_file *seq, void *p)
> +{
> + struct dentry *root = seq->private;
> + unsigned long item;
> + unsigned long host;
> + unsigned long data;
> + char name[10];
> + char *ptr;
> +
> + for (host = 0; host < 10; host++) {
> + for (item = 0; item < 512; item++) {
> + ptr = qcom_smem_get(host, item, NULL);
> + if (IS_ERR(ptr))
> + continue;
> +
> + sprintf(name, "%ld-%ld", host, item);
> +
> + data = host << 16 | item;
> + debugfs_create_file(name, 0400, root,
> + (void *)data, &smem_debugfs_item_ops);
So IIUC user invokes scan file which creates additional files, right?
Additional invoke will do that as well..?
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int smem_debugfs_rescan_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, smem_debugfs_rescan, inode->i_private);
> +}
> +
> +static const struct file_operations smem_debugfs_rescan_ops = {
> + .open = smem_debugfs_rescan_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
Here as well?
> +
> +static struct dentry *smem_debugfs_root;
> +
> +static int __init qcom_smem_debugfs_init(void)
> +{
> + smem_debugfs_root = debugfs_create_dir("qcom_smem", NULL);
> + debugfs_create_file("rescan", 0400, smem_debugfs_root,
> + smem_debugfs_root, &smem_debugfs_rescan_ops);
> +
> + return 0;
> +}
> +
> +static void __exit qcom_smem_debugfs_exit(void)
> +{
> + debugfs_remove_recursive(smem_debugfs_root);
> +}
> +
> +module_init(qcom_smem_debugfs_init);
> +module_exit(qcom_smem_debugfs_exit);
> +
> +MODULE_DESCRIPTION("Qualcomm SMEM debugfs driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.29.2
--
~Vinod
