Re: [PATCH v3 4/9] misc: fastrpc: Add static PD restart support
From: Bharath Kumar V
Date: Tue Jun 04 2024 - 05:23:41 EST
On 6/3/2024 4:23 PM, Caleb Connolly wrote:
Hi Ekansh,
On 30/05/2024 12:20, Ekansh Gupta wrote:
Static PDs on the audio and sensor domains are expected to support
PD restart. The kernel resource handling for the PDs are expected
to be handled by fastrpc driver. For this, there is a requirement
of PD service locator to get the event notifications for static PD
services. Also when events are received, the driver needs to handle
based on PD states. Added changes to add service locator for audio
and sensor domain static PDs and handle the PD restart sequence.
Thanks for the patch, I wanted to bring up a larger issue which I've
been noticing with the fastrpc driver.
This file is now >2.5k LOC, and to my knowledge it features:
* Two different memory mapping/unmapping interfaces to the DSP (three if
you count dmabufs!)
* Different branching codepaths for static vs dynamic processes (with
totally different lifetimes).
* Over 8 structs just for state management, with the largest being >1500
bytes
* Zero context for which code paths are relevant for which contexts
Your series is a combination of bug fixes and cleanup which span most of
the file -- suggesting that the state management is also spread all ove
rthe file. Even for someone with some familiarity with the driver these
patches are really non-trivial to review (patch 5 being a good example
of this), while in addition you introduce new features like this in
patch. This doesn't make for a coherent story for reviewers.
On top of that, there is very minimal, if any comments in this hugely
complex code, and seemingly zero consideration for how to model state or
the lifetime of objects.
Finally, there is next-to-no public documentation or easily obtained
(and used) userspace for this driver. Certainly nothing that I could use
to offer a Tested-by on your patches.
I am not the maintainer, so while it's not my place, I want to offer
some suggestions here:
1. Split the fastrpc driver up into more bite-size chunks which can
actually be reasoned about (I would start by splitting the
implementation details out from the business logic, and then further
abstracting out the static PD support, PDR, etc. Just the "invoke"
mechanism should be in it's own file with it's own state...).
2. Add detailed documentation explaining fastrpc from at least a high
level (ideally with lower level and driver details too), and code
comments (where relevant).
3. Release (and maintain) a reference tool(s) that can be used to
validate the driver and better understand proposed new features (you
could take inspiration from https://gitlab.com/flamingradian/sensh/).
A mechanism to test at least parts of this driver without needing a DSP
on the other end would likely help a lot here, but that's obviously a
much larger scope.
Please let me know your thoughts.
Kind Regards,
Thank you for reviewing the driver and the patches. Your feedback is
greatly appreciated.
As you mentioned, our current driver is a large file containing various
APIs to support multiple features. We are actively discussing
modularizing the driver to enhance clarity and improve understanding.
Additionally, we are in the process of creating basic documentation, as
well as feature-specific documentation for better clarity.
Our latest user space code is available on GitHub at
github.com/quic/fastrpc. Feel free to explore it, and please let us know
if you have any feedback or need further assistance. We’re committed to
continuous improvement.
For testing purposes, we’ve the Hexagon SDK by Qualcomm to the public.
You can download it from the Qualcomm developer network. The SDK
includes examples covering all the features of fastRPC, along with
comprehensive documentation. If you encounter any issues accessing the
Hexagon SDK or have suggestions for improving the documentation, feel
free to reach out.
Best Regards,
Bharath
Signed-off-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
---
drivers/misc/Kconfig | 2 +
drivers/misc/fastrpc.c | 205 ++++++++++++++++++++++++++++++++++++++---
2 files changed, 195 insertions(+), 12 deletions(-)
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index faf983680040..e2d83cd085b5 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -280,8 +280,10 @@ config QCOM_FASTRPC
tristate "Qualcomm FastRPC"
depends on ARCH_QCOM || COMPILE_TEST
depends on RPMSG
+ depends on NET
select DMA_SHARED_BUFFER
select QCOM_SCM
+ select QCOM_PDR_HELPERS
help
Provides a communication mechanism that allows for clients to
make remote method invocations across processor boundary to
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 3e1ab58038ed..d115860fc356 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -22,6 +22,7 @@
#include <linux/firmware/qcom/qcom_scm.h>
#include <uapi/misc/fastrpc.h>
#include <linux/of_reserved_mem.h>
+#include <linux/soc/qcom/pdr.h>
#define ADSP_DOMAIN_ID (0)
#define MDSP_DOMAIN_ID (1)
@@ -29,6 +30,7 @@
#define CDSP_DOMAIN_ID (3)
#define FASTRPC_DEV_MAX 4 /* adsp, mdsp, slpi, cdsp*/
#define FASTRPC_MAX_SESSIONS 14
+#define FASTRPC_MAX_SPD 4
#define FASTRPC_MAX_VMIDS 16
#define FASTRPC_ALIGN 128
#define FASTRPC_MAX_FDLIST 16
@@ -105,6 +107,18 @@
#define miscdev_to_fdevice(d) container_of(d, struct fastrpc_device,
miscdev)
+#define AUDIO_PDR_SERVICE_LOCATION_CLIENT_NAME "audio_pdr_adsp"
+#define AUDIO_PDR_ADSP_SERVICE_NAME "avs/audio"
+#define ADSP_AUDIOPD_NAME "msm/adsp/audio_pd"
+
+#define SENSORS_PDR_ADSP_SERVICE_LOCATION_CLIENT_NAME
"sensors_pdr_adsp"
+#define SENSORS_PDR_ADSP_SERVICE_NAME "tms/servreg"
+#define ADSP_SENSORPD_NAME "msm/adsp/sensor_pd"
+
+#define SENSORS_PDR_SLPI_SERVICE_LOCATION_CLIENT_NAME "sensors_pdr_slpi"
+#define SENSORS_PDR_SLPI_SERVICE_NAME
SENSORS_PDR_ADSP_SERVICE_NAME
+#define SLPI_SENSORPD_NAME "msm/slpi/sensor_pd"
+
static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
"sdsp", "cdsp"};
struct fastrpc_phy_page {
@@ -259,6 +273,15 @@ struct fastrpc_session_ctx {
bool valid;
};
+struct fastrpc_static_pd {
+ char *servloc_name;
+ char *spdname;
+ void *pdrhandle;
+ struct fastrpc_channel_ctx *cctx;
+ struct fastrpc_user *fl;
+ bool ispdup;
+};
+
struct fastrpc_channel_ctx {
int domain_id;
int sesscount;
@@ -266,6 +289,7 @@ struct fastrpc_channel_ctx {
struct qcom_scm_vmperm vmperms[FASTRPC_MAX_VMIDS];
struct rpmsg_device *rpdev;
struct fastrpc_session_ctx session[FASTRPC_MAX_SESSIONS];
+ struct fastrpc_static_pd spd[FASTRPC_MAX_SPD];
spinlock_t lock;
struct idr ctx_idr;
struct list_head users;
@@ -297,10 +321,12 @@ struct fastrpc_user {
struct fastrpc_channel_ctx *cctx;
struct fastrpc_session_ctx *sctx;
struct fastrpc_buf *init_mem;
+ struct fastrpc_static_pd *spd;
int tgid;
int pd;
bool is_secure_dev;
+ char *servloc_name;
/* Lock for lists */
spinlock_t lock;
/* lock for allocations */
@@ -1230,12 +1256,33 @@ static bool is_session_rejected(struct
fastrpc_user *fl, bool unsigned_pd_reques
return false;
}
+static struct fastrpc_static_pd *fastrpc_get_spd_session(
+ struct fastrpc_user *fl)
+{
+ int i;
+ struct fastrpc_static_pd *spd = NULL;
+ struct fastrpc_channel_ctx *cctx = fl->cctx;
+
+ for (i = 0; i < FASTRPC_MAX_SPD ; i++) {
+ if (!cctx->spd[i].servloc_name)
+ continue;
+ if (!strcmp(fl->servloc_name, cctx->spd[i].servloc_name)) {
+ spd = &cctx->spd[i];
+ spd->fl = fl;
+ break;
+ }
+ }
+
+ return spd;
+}
+
static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
char __user *argp)
{
struct fastrpc_init_create_static init;
struct fastrpc_invoke_args *args;
struct fastrpc_phy_page pages[1];
+ struct fastrpc_static_pd *spd = NULL;
char *name;
int err;
struct {
@@ -1270,6 +1317,19 @@ static int
fastrpc_init_create_static_process(struct fastrpc_user *fl,
goto err_name;
}
+ fl->servloc_name = AUDIO_PDR_SERVICE_LOCATION_CLIENT_NAME;
+
+ spd = fastrpc_get_spd_session(fl);
+ if (!spd) {
+ err = -EUSERS;
+ goto err_name;
+ }
+
+ if (!spd->ispdup) {
+ err = -ENOTCONN;
+ goto err_name;
+ }
+ fl->spd = spd;
if (!fl->cctx->remote_heap) {
err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
&fl->cctx->remote_heap);
@@ -1645,6 +1705,7 @@ static int fastrpc_dmabuf_alloc(struct
fastrpc_user *fl, char __user *argp)
static int fastrpc_init_attach(struct fastrpc_user *fl, int pd)
{
struct fastrpc_invoke_args args[1];
+ struct fastrpc_static_pd *spd = NULL;
int tgid = fl->tgid;
u32 sc;
@@ -1654,6 +1715,22 @@ static int fastrpc_init_attach(struct
fastrpc_user *fl, int pd)
sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_ATTACH, 1, 0);
fl->pd = pd;
+ if (pd == SENSORS_PD) {
+ if (fl->cctx->domain_id == ADSP_DOMAIN_ID)
+ fl->servloc_name =
SENSORS_PDR_ADSP_SERVICE_LOCATION_CLIENT_NAME;
+ else if (fl->cctx->domain_id == SDSP_DOMAIN_ID)
+ fl->servloc_name =
SENSORS_PDR_SLPI_SERVICE_LOCATION_CLIENT_NAME;
+
+ spd = fastrpc_get_spd_session(fl);
+ if (!spd)
+ return -EUSERS;
+
+ if (!spd->ispdup)
+ return -ENOTCONN;
+
+ fl->spd = spd;
+ }
+
return fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE,
sc, &args[0]);
}
@@ -2129,6 +2206,64 @@ static long fastrpc_device_ioctl(struct file
*file, unsigned int cmd,
return err;
}
+static void fastrpc_notify_users(struct fastrpc_user *user)
+{
+ struct fastrpc_invoke_ctx *ctx;
+
+ spin_lock(&user->lock);
+ list_for_each_entry(ctx, &user->pending, node) {
+ ctx->retval = -EPIPE;
+ complete(&ctx->work);
+ }
+ spin_unlock(&user->lock);
+}
+
+static void fastrpc_notify_pdr_drivers(struct fastrpc_channel_ctx *cctx,
+ char *servloc_name)
+{
+ struct fastrpc_user *fl;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cctx->lock, flags);
+ list_for_each_entry(fl, &cctx->users, user) {
+ if (fl->servloc_name && !strcmp(servloc_name, fl->servloc_name))
+ fastrpc_notify_users(fl);
+ }
+ spin_unlock_irqrestore(&cctx->lock, flags);
+}
+
+static void fastrpc_pdr_cb(int state, char *service_path, void *priv)
+{
+ struct fastrpc_static_pd *spd = (struct fastrpc_static_pd *)priv;
+ struct fastrpc_channel_ctx *cctx;
+
+ if (!spd)
+ return;
+
+ cctx = spd->cctx;
+ switch (state) {
+ case SERVREG_SERVICE_STATE_DOWN:
+ dev_info(&cctx->rpdev->dev,
+ "%s: %s (%s) is down for PDR on %s\n",
+ __func__, spd->spdname,
+ spd->servloc_name,
+ domains[cctx->domain_id]);
+ spd->ispdup = false;
+ fastrpc_notify_pdr_drivers(cctx, spd->servloc_name);
+ break;
+ case SERVREG_SERVICE_STATE_UP:
+ dev_info(&cctx->rpdev->dev,
+ "%s: %s (%s) is up for PDR on %s\n",
+ __func__, spd->spdname,
+ spd->servloc_name,
+ domains[cctx->domain_id]);
+ spd->ispdup = true;
+ break;
+ default:
+ break;
+ }
+}
+
static const struct file_operations fastrpc_fops = {
.open = fastrpc_device_open,
.release = fastrpc_device_release,
@@ -2248,6 +2383,39 @@ static int fastrpc_device_register(struct
device *dev, struct fastrpc_channel_ct
return err;
}
+static int fastrpc_setup_service_locator(struct fastrpc_channel_ctx
*cctx, char *client_name,
+ char *service_name, char *service_path, int domain, int
spd_session)
+{
+ int err = 0;
+ struct pdr_handle *handle = NULL;
+ struct pdr_service *service = NULL;
+
+ /* Register the service locator's callback function */
+ handle = pdr_handle_alloc(fastrpc_pdr_cb, &cctx->spd[spd_session]);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ goto bail;
+ }
+ cctx->spd[spd_session].pdrhandle = handle;
+ cctx->spd[spd_session].servloc_name = client_name;
+ cctx->spd[spd_session].spdname = service_path;
+ cctx->spd[spd_session].cctx = cctx;
+ service = pdr_add_lookup(handle, service_name, service_path);
+ if (IS_ERR(service)) {
+ err = PTR_ERR(service);
+ goto bail;
+ }
+ pr_info("fastrpc: %s: pdr_add_lookup enabled for %s (%s, %s)\n",
+ __func__, service_name, client_name, service_path);
+
+bail:
+ if (err) {
+ pr_warn("fastrpc: %s: failed for %s (%s, %s)with err %d\n",
+ __func__, service_name, client_name, service_path, err);
+ }
+ return err;
+}
+
static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
{
struct device *rdev = &rpdev->dev;
@@ -2326,6 +2494,25 @@ static int fastrpc_rpmsg_probe(struct
rpmsg_device *rpdev)
goto fdev_error;
}
+ if (domain_id == ADSP_DOMAIN_ID) {
+ err = fastrpc_setup_service_locator(data,
AUDIO_PDR_SERVICE_LOCATION_CLIENT_NAME,
+ AUDIO_PDR_ADSP_SERVICE_NAME, ADSP_AUDIOPD_NAME,
domain_id, 0);
+ if (err)
+ goto populate_error;
+
+ err = fastrpc_setup_service_locator(data,
+ SENSORS_PDR_ADSP_SERVICE_LOCATION_CLIENT_NAME,
+ SENSORS_PDR_ADSP_SERVICE_NAME, ADSP_SENSORPD_NAME,
domain_id, 1);
+ if (err)
+ goto populate_error;
+ } else if (domain_id == SDSP_DOMAIN_ID) {
+ err = fastrpc_setup_service_locator(data,
+ SENSORS_PDR_SLPI_SERVICE_LOCATION_CLIENT_NAME,
+ SENSORS_PDR_SLPI_SERVICE_NAME, SLPI_SENSORPD_NAME,
domain_id, 0);
+ if (err)
+ goto populate_error;
+ }
+
kref_init(&data->refcount);
dev_set_drvdata(&rpdev->dev, data);
@@ -2355,24 +2542,13 @@ static int fastrpc_rpmsg_probe(struct
rpmsg_device *rpdev)
return err;
}
-static void fastrpc_notify_users(struct fastrpc_user *user)
-{
- struct fastrpc_invoke_ctx *ctx;
-
- spin_lock(&user->lock);
- list_for_each_entry(ctx, &user->pending, node) {
- ctx->retval = -EPIPE;
- complete(&ctx->work);
- }
- spin_unlock(&user->lock);
-}
-
static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
{
struct fastrpc_channel_ctx *cctx = dev_get_drvdata(&rpdev->dev);
struct fastrpc_buf *buf, *b;
struct fastrpc_user *user;
unsigned long flags;
+ int i;
/* No invocations past this point */
spin_lock_irqsave(&cctx->lock, flags);
@@ -2393,6 +2569,11 @@ static void fastrpc_rpmsg_remove(struct
rpmsg_device *rpdev)
if (cctx->remote_heap)
fastrpc_buf_free(cctx->remote_heap);
+ for (i = 0; i < FASTRPC_MAX_SPD; i++) {
+ if (cctx->spd[i].pdrhandle)
+ pdr_handle_release(cctx->spd[i].pdrhandle);
+ }
+
of_platform_depopulate(&rpdev->dev);
fastrpc_channel_ctx_put(cctx);