add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/fsi/fsi-core.c
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..
@@ -1,16 +1,8 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * FSI core driver
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  *
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  * Copyright (C) IBM Corporation 2016
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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  *
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  * TODO:
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  *  - Rework topology
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..
@@ -58,6 +50,7 @@
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 #define FSI_SMODE		0x0	/* R/W: Mode register */
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 #define FSI_SISC		0x8	/* R/W: Interrupt condition */
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 #define FSI_SSTAT		0x14	/* R  : Slave status */
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+#define FSI_SLBUS		0x30	/* W  : LBUS Ownership */
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 #define FSI_LLMODE		0x100	/* R/W: Link layer mode register */
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55
 
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 /*
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@@ -73,6 +66,11 @@
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 #define FSI_SMODE_SD_MASK	0xf		/* Send delay mask */
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 #define FSI_SMODE_LBCRR_SHIFT	8		/* Clk ratio shift */
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 #define FSI_SMODE_LBCRR_MASK	0xf		/* Clk ratio mask */
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+
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+/*
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+ * SLBUS fields
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+ */
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+#define FSI_SLBUS_FORCE		0x80000000	/* Force LBUS ownership */
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 /*
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  * LLMODE fields
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@@ -989,7 +987,7 @@
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 	uint32_t cfam_id;
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 	struct fsi_slave *slave;
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 	uint8_t crc;
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-	__be32 data, llmode;
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+	__be32 data, llmode, slbus;
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 	int rc;
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992
 
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 	/* Currently, we only support single slaves on a link, and use the
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@@ -1059,6 +1057,14 @@
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 			slave->chip_id = prop;
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1058
 
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 	}
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+
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+	slbus = cpu_to_be32(FSI_SLBUS_FORCE);
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+	rc = fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SLBUS,
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+			      &slbus, sizeof(slbus));
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+	if (rc)
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+		dev_warn(&master->dev,
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+			 "can't set slbus on slave:%02x:%02x %d\n", link, id,
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+			 rc);
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1068
 
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 	rc = fsi_slave_set_smode(slave);
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 	if (rc) {
..
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@@ -1162,10 +1168,18 @@
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 	return rc;
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 }
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+static int fsi_master_link_disable(struct fsi_master *master, int link)
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+{
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+	if (master->link_enable)
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+		return master->link_enable(master, link, false);
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+
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+	return 0;
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+}
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+
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 static int fsi_master_link_enable(struct fsi_master *master, int link)
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 {
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 	if (master->link_enable)
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-		return master->link_enable(master, link);
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+		return master->link_enable(master, link, true);
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 	return 0;
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 }
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@@ -1200,12 +1214,15 @@
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 		}
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 		rc = fsi_master_break(master, link);
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 		if (rc) {
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+			fsi_master_link_disable(master, link);
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 			dev_dbg(&master->dev,
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 				"break to link %d failed: %d\n", link, rc);
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 			continue;
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 		}
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-		fsi_slave_init(master, link, 0);
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+		rc = fsi_slave_init(master, link, 0);
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+		if (rc)
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+			fsi_master_link_disable(master, link);
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 	}
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 	return 0;
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@@ -1272,6 +1289,19 @@
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 static DEVICE_ATTR(break, 0200, NULL, master_break_store);
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+static struct attribute *master_attrs[] = {
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+	&dev_attr_break.attr,
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+	&dev_attr_rescan.attr,
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+	NULL
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+};
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+
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+ATTRIBUTE_GROUPS(master);
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+
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+static struct class fsi_master_class = {
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+	.name = "fsi-master",
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+	.dev_groups = master_groups,
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+};
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+
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 int fsi_master_register(struct fsi_master *master)
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 {
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 	int rc;
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@@ -1279,24 +1309,14 @@
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 	mutex_init(&master->scan_lock);
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 	master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
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+	if (master->idx < 0)
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+		return master->idx;
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+
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 	dev_set_name(&master->dev, "fsi%d", master->idx);
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+	master->dev.class = &fsi_master_class;
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 	rc = device_register(&master->dev);
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 	if (rc) {
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-		ida_simple_remove(&master_ida, master->idx);
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-		return rc;
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-	}
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-
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-	rc = device_create_file(&master->dev, &dev_attr_rescan);
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-	if (rc) {
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-		device_del(&master->dev);
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-		ida_simple_remove(&master_ida, master->idx);
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-		return rc;
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-	}
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-
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-	rc = device_create_file(&master->dev, &dev_attr_break);
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-	if (rc) {
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-		device_del(&master->dev);
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 		ida_simple_remove(&master_ida, master->idx);
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 		return rc;
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 	}
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@@ -1381,8 +1401,15 @@
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 	rc = bus_register(&fsi_bus_type);
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 	if (rc)
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 		goto fail_bus;
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+
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+	rc = class_register(&fsi_master_class);
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+	if (rc)
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+		goto fail_class;
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+
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 	return 0;
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+ fail_class:
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+	bus_unregister(&fsi_bus_type);
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  fail_bus:
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 	unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
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 	return rc;
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@@ -1391,6 +1418,7 @@
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 static void fsi_exit(void)
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 {
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+	class_unregister(&fsi_master_class);
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 	bus_unregister(&fsi_bus_type);
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 	unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
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 	ida_destroy(&fsi_minor_ida);