From 3449744146b0a1b68810b81bd51fe5ef285e2388 Mon Sep 17 00:00:00 2001
From: Bjorn Andersson <bjorn.andersson@linaro.org>
Date: Sat, 21 Nov 2020 00:02:39 -0600
Subject: [PATCH] rproc: Support -s for PAS based remoteproc as well

The old mechanism searched for remoteproc instances from the
qcom_q6v5_mss driver, but in modern platforms the MSA based remoteproc
model has been replaced by the PAS based one. As such we use the common
qcom_q6v5_pas driver - as with other subsystems.

Use the modalias to find remoteproc drivers with the mpss-pas or mss-pil
compatible to find these, and fall back to the old heuristics if this
fails.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 rproc.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 84 insertions(+), 11 deletions(-)

diff --git a/rproc.c b/rproc.c
index a471b3c..d104490 100644
--- a/rproc.c
+++ b/rproc.c
@@ -13,13 +13,74 @@
 #include "rmtfs.h"
 
 #define RPROC_BASE_PATH		"/sys/bus/platform/drivers/qcom-q6v5-mss/"
+#define RPROC_CLASS_PATH	"/sys/class/remoteproc/"
 
 static pthread_t start_thread;
 static pthread_t stop_thread;
 static int rproc_state_fd;
 static int rproc_pipe[2];
 
-int rproc_init(void)
+static int rproc_init_by_modalias(void)
+{
+	struct dirent *rproc_de;
+	char modalias[256];
+	DIR *base_dir;
+	int modalias_fd;
+	int rproc_fd;
+	int state_fd = -1;
+	int base_fd;
+	int ret;
+
+	base_fd = open(RPROC_CLASS_PATH, O_RDONLY | O_DIRECTORY);
+	if (base_fd < 0)
+		return -1;
+
+	base_dir = fdopendir(base_fd);
+	if (!base_dir) {
+		fprintf(stderr, "failed to open remoteproc class path\n");
+		close(base_fd);
+		return -1;
+	}
+
+	while (state_fd < 0 && (rproc_de = readdir(base_dir)) != NULL) {
+		if (!strcmp(rproc_de->d_name, ".") ||
+		    !strcmp(rproc_de->d_name, ".."))
+			continue;
+
+		rproc_fd = openat(base_fd, rproc_de->d_name, O_RDONLY | O_DIRECTORY);
+		if (rproc_fd < 0)
+			continue;
+
+		modalias_fd = openat(rproc_fd, "device/modalias", O_RDONLY);
+		if (modalias_fd < 0)
+			goto close_rproc_fd;
+
+		ret = read(modalias_fd, modalias, sizeof(modalias));
+		if (ret < 0)
+			goto close_modalias_fd;
+
+		if (!strstr(modalias, "-mpss-pas") && !strstr(modalias, "-mss-pil"))
+			goto close_modalias_fd;
+
+		state_fd = openat(rproc_fd, "state", O_WRONLY);
+		if (state_fd < 0) {
+			fprintf(stderr,
+				"unable to open remoteproc \"state\" control file of %s\n",
+				rproc_de->d_name);
+		}
+
+close_modalias_fd:
+		close(modalias_fd);
+close_rproc_fd:
+		close(rproc_fd);
+	}
+	closedir(base_dir);
+	close(base_fd);
+
+	return state_fd;
+}
+
+static int rproc_init_by_mss_driver(void)
 {
 	struct dirent *device_de;
 	struct dirent *rproc_de;
@@ -28,10 +89,8 @@ int rproc_init(void)
 	DIR *base_dir;
 	int device_fd;
 	int rproc_fd;
+	int state_fd = -1;
 	int base_fd;
-	int ret;
-
-	rproc_state_fd = -1;
 
 	base_fd = open(RPROC_BASE_PATH, O_RDONLY | O_DIRECTORY);
 	if (base_fd < 0)
@@ -44,7 +103,7 @@ int rproc_init(void)
 		return -1;
 	}
 
-	while (rproc_state_fd < 0 && (device_de = readdir(base_dir)) != NULL) {
+	while (state_fd < 0 && (device_de = readdir(base_dir)) != NULL) {
 		if (!strcmp(device_de->d_name, ".") ||
 		    !strcmp(device_de->d_name, ".."))
 			continue;
@@ -60,7 +119,7 @@ int rproc_init(void)
 		}
 
 		rproc_dir = fdopendir(rproc_base_fd);
-		while (rproc_state_fd < 0 && (rproc_de = readdir(rproc_dir)) != NULL) {
+		while (state_fd < 0 && (rproc_de = readdir(rproc_dir)) != NULL) {
 			if (!strcmp(rproc_de->d_name, ".") ||
 			    !strcmp(rproc_de->d_name, ".."))
 				continue;
@@ -69,8 +128,8 @@ int rproc_init(void)
 			if (rproc_fd < 0)
 				continue;
 
-			rproc_state_fd = openat(rproc_fd, "state", O_WRONLY);
-			if (rproc_state_fd < 0) {
+			state_fd = openat(rproc_fd, "state", O_WRONLY);
+			if (state_fd < 0) {
 				fprintf(stderr,
 					"unable to open remoteproc \"state\" control file of %s\n",
 					device_de->d_name);
@@ -86,15 +145,29 @@ int rproc_init(void)
 	closedir(base_dir);
 	close(base_fd);
 
-	if (rproc_state_fd < 0)
-		return -1;
+	return state_fd;
+}
+
+int rproc_init(void)
+{
+	int state_fd;
+	int ret;
+
+	state_fd = rproc_init_by_modalias();
+	if (state_fd < 0) {
+		state_fd = rproc_init_by_mss_driver();
+		if (state_fd < 0)
+			return -1;
+	}
 
 	ret = pipe(rproc_pipe);
 	if (ret < 0) {
-		close(rproc_state_fd);
+		close(state_fd);
 		return -1;
 	}
 
+	rproc_state_fd = state_fd;
+
 	return rproc_pipe[0];
 }