libdbg: Introduce kernel FSI driver backend

Creatively named 'kernel', this uses the SoftFSI aka OpenFSI aka fsi
kernel driver.

This backend triggers a probe of all attached FSI devices by the
 kernel. This assumes a single slave appears in sysfs, and uses the
 'raw' device to perform reads and writes directly to the CFAM address
 space and SCOM space.

Signed-off-by: Joel Stanley <joel@jms.id.au>

2 files changed, 186 insertions, 0 deletions

diff --git a/libpdbg/kernel.c b/libpdbg/kernel.c
new file mode 100644
index 0000000..2694ba0
--- /dev/null
+++ b/libpdbg/kernel.c
@@ -0,0 +1,184 @@
+/* Copyright 2016 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <errno.h>
+#include <err.h>
+#include <inttypes.h>
+
+#include "bitutils.h"
+#include "operations.h"
+#include "target.h"
+
+#define FSI_SCAN_PATH "/sys/devices/platform/fsi-master/scan"
+#define FSI_CFAM_PATH "/sys/devices/platform/fsi-master/slave@00:00/raw"
+#define FSI_SCOM_PATH "/sys/devices/platform/fsi-master/slave@00:00/"
+
+int fsi_fd;
+int scom_fd;
+
+static int kernel_putscom(struct target *target, uint64_t addr, uint64_t value)
+{
+	int rc;
+
+	rc = lseek(scom_fd, addr, SEEK_SET);
+	if (rc < 0) {
+		warn("Failed to seek %s", FSI_SCOM_PATH);
+		return errno;
+	}
+
+	rc = write(scom_fd, &value, sizeof(value));
+	if (rc < 0) {
+		warn("Failed to write to 0x%016llx", addr);
+		return errno;
+	}
+
+	return 0;
+
+}
+
+static int kernel_getscom(struct target *target, uint64_t addr, uint64_t *value)
+{
+	int rc;
+
+	rc = lseek(fsi_fd, addr, SEEK_SET);
+	if (rc < 0) {
+		warn("Failed to seek %s", FSI_SCOM_PATH);
+		return errno;
+	}
+
+	rc = read(fsi_fd, value, sizeof(*value));
+	if (rc < 0) {
+		warn("Failed to read from 0x%016llx", addr);
+		return errno;
+	}
+
+	return 0;
+
+}
+
+static int kernel_fsi_getcfam(struct target *target, uint64_t addr64, uint64_t *value)
+{
+	int rc;
+	uint32_t addr = (addr64 & 0x1fff00) | ((addr64 & 0xff) << 2);
+
+	rc = lseek(fsi_fd, addr, SEEK_SET);
+	if (rc < 0) {
+		warn("Failed to seek %s", FSI_CFAM_PATH);
+		return errno;
+	}
+
+	rc = read(fsi_fd, value, 4);
+	if (rc < 0) {
+		warn("Failed to read from 0x%08x (%016llx)", (uint32_t)addr, addr64);
+		return errno;
+	}
+
+	return 0;
+}
+
+static int kernel_fsi_putcfam(struct target *target, uint64_t addr64, uint64_t data)
+{
+	int rc;
+	uint32_t addr = (addr64 & 0x1fff00) | ((addr64 & 0xff) << 2);
+
+	rc = lseek(fsi_fd, addr, SEEK_SET);
+	if (rc < 0) {
+		warn("Failed to seek %s", FSI_CFAM_PATH);
+		return errno;
+	}
+
+	rc = write(fsi_fd, &data, 4);
+	if (rc < 0) {
+		warn("Failed to write to 0x%08x (%016llx)", addr, addr64);
+		return errno;
+	}
+
+	return 0;
+}
+
+static void kernel_fsi_destroy(struct target *target)
+{
+	close(fsi_fd);
+}
+
+static void kernel_fsi_scan_devices(void)
+{
+	const char one = '1';
+	int rc, fd;
+
+	fd = open(FSI_SCAN_PATH, O_WRONLY | O_SYNC);
+	if (fd < 0)
+		err(errno, "Unable to open %s", FSI_SCAN_PATH);
+
+	rc = write(fd, &one, sizeof(one));
+	if (rc < 0)
+		err(errno, "Unable to write to %s", FSI_SCAN_PATH);
+
+	close(fd);
+}
+
+int kernel_fsi_target_init(struct target *target, const char *name,
+			   struct target *next)
+{
+	uint64_t value;
+
+	if (!fsi_fd) {
+		int tries = 5;
+
+		while (tries) {
+			/* Open first raw device */
+			fsi_fd = open(FSI_CFAM_PATH, O_RDWR | O_SYNC);
+			if (fsi_fd >= 0)
+				goto found;
+			tries--;
+
+			/* Scan */
+			kernel_fsi_scan_devices();
+			sleep(1);
+		}
+		if (fsi_fd < 0)
+			err(errno, "Unable to open %s", FSI_CFAM_PATH);
+
+	}
+found:
+	/* No cascaded devices after this one. */
+	assert(next == NULL);
+	target_init(target, name, 0, kernel_fsi_getcfam, kernel_fsi_putcfam,
+		    kernel_fsi_destroy, next);
+
+	/* Read chip id */
+	CHECK_ERR(read_target(target, 0xc09, &value));
+	target->chip_type = get_chip_type(value);
+
+	return 0;
+}
+
+int kernel_fsi2pib_target_init(struct target *target, const char *name,
+				uint64_t base, struct target *next)
+{
+	target_init(target, name, base, kernel_getscom, kernel_putscom, NULL,
+			next);
+
+	return 0;
+
+}
diff --git a/libpdbg/operations.h b/libpdbg/operations.h
index a3e66c6..76a1ca8 100644
--- a/libpdbg/operations.h
+++ b/libpdbg/operations.h
@@ -74,7 +74,9 @@ int fsi_target_init(struct target *target, const char *name, enum fsi_system_typ
 int fsi_target_probe(struct target *targets, int max_target_count);
 int i2c_target_init(struct target *target, const char *name, struct target *next,
 		    const char *bus, int addr);
+int kernel_fsi_target_init(struct target *target, const char *name, struct target *next);
 int fsi2pib_target_init(struct target *target, const char *name, uint64_t base, struct target *next);
+int kernel_fsi2pib_target_init(struct target *target, const char *name, uint64_t base, struct target *next);
 int opb_target_init(struct target *target, const char *name, uint64_t base, struct target *next);
 enum chip_type get_chip_type(uint64_t chip_id);
 int thread_target_init(struct target *thread, const char *name, uint64_t thread_id, struct target *next);