net: ipa: introduce gsi_reg_init()

Create a new source file "gsi_reg.c", and in it, introduce a new
function to encapsulate initializing GSI registers, including
looking up and I/O mapping their memory.

Create gsi_reg_exit() as the inverse of the init function.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/Makefile

@@ -7,8 +7,8 @@ IPA_VERSIONS		:=	3.1 3.5.1 4.2 4.5 4.7 4.9 4.11
 obj-$(CONFIG_QCOM_IPA)	+=	ipa.o
 
 ipa-y			:=	ipa_main.o ipa_power.o ipa_reg.o ipa_mem.o \
-				ipa_table.o ipa_interrupt.o gsi.o gsi_trans.o \
-				ipa_gsi.o ipa_smp2p.o ipa_uc.o \
+				ipa_table.o ipa_interrupt.o gsi.o gsi_reg.o \
+				gsi_trans.o ipa_gsi.o ipa_smp2p.o ipa_uc.o \
 				ipa_endpoint.o ipa_cmd.o ipa_modem.o \
 				ipa_resource.o ipa_qmi.o ipa_qmi_msg.o \
 				ipa_sysfs.o

drivers/net/ipa/gsi.c

 // SPDX-License-Identifier: GPL-2.0
 
 /* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
- * Copyright (C) 2018-2022 Linaro Ltd.
+ * Copyright (C) 2018-2023 Linaro Ltd.
  */
 
 #include <linux/types.h>
@@ -2241,67 +2241,37 @@ int gsi_init(struct gsi *gsi, struct platform_device *pdev,
 	     enum ipa_version version, u32 count,
 	     const struct ipa_gsi_endpoint_data *data)
 {
-	struct device *dev = &pdev->dev;
-	struct resource *res;
-	resource_size_t size;
-	u32 adjust;
 	int ret;
 
 	gsi_validate_build();
 
-	gsi->dev = dev;
+	gsi->dev = &pdev->dev;
 	gsi->version = version;
 
 	/* GSI uses NAPI on all channels.  Create a dummy network device
 	 * for the channel NAPI contexts to be associated with.
 	 */
 	init_dummy_netdev(&gsi->dummy_dev);
-
-	/* Get GSI memory range and map it */
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gsi");
-	if (!res) {
-		dev_err(dev, "DT error getting \"gsi\" memory property\n");
-		return -ENODEV;
-	}
-
-	size = resource_size(res);
-	if (res->start > U32_MAX || size > U32_MAX - res->start) {
-		dev_err(dev, "DT memory resource \"gsi\" out of range\n");
-		return -EINVAL;
-	}
-
-	/* Make sure we can make our pointer adjustment if necessary */
-	adjust = gsi->version < IPA_VERSION_4_5 ? 0 : GSI_EE_REG_ADJUST;
-	if (res->start < adjust) {
-		dev_err(dev, "DT memory resource \"gsi\" too low (< %u)\n",
-			adjust);
-		return -EINVAL;
-	}
-
-	gsi->virt_raw = ioremap(res->start, size);
-	if (!gsi->virt_raw) {
-		dev_err(dev, "unable to remap \"gsi\" memory\n");
-		return -ENOMEM;
-	}
-	/* Most registers are accessed using an adjusted register range */
-	gsi->virt = gsi->virt_raw - adjust;
-
 	init_completion(&gsi->completion);
 
+	ret = gsi_reg_init(gsi, pdev);
+	if (ret)
+		return ret;
+
 	ret = gsi_irq_init(gsi, pdev);	/* No matching exit required */
 	if (ret)
-		goto err_iounmap;
+		goto err_reg_exit;
 
 	ret = gsi_channel_init(gsi, count, data);
 	if (ret)
-		goto err_iounmap;
+		goto err_reg_exit;
 
 	mutex_init(&gsi->mutex);
 
 	return 0;
 
-err_iounmap:
-	iounmap(gsi->virt_raw);
+err_reg_exit:
+	gsi_reg_exit(gsi);
 
 	return ret;
 }
@@ -2311,7 +2281,7 @@ void gsi_exit(struct gsi *gsi)
 {
 	mutex_destroy(&gsi->mutex);
 	gsi_channel_exit(gsi);
-	iounmap(gsi->virt_raw);
+	gsi_reg_exit(gsi);
 }
 
 /* The maximum number of outstanding TREs on a channel.  This limits

drivers/net/ipa/gsi_reg.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (C) 2023 Linaro Ltd. */
+
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include "gsi.h"
+#include "gsi_reg.h"
+
+/* GSI EE registers as a group are shifted downward by a fixed constant amount
+ * for IPA versions 4.5 and beyond.  This applies to all GSI registers we use
+ * *except* the ones that disable inter-EE interrupts for channels and event
+ * channels.
+ *
+ * The "raw" (not adjusted) GSI register range is mapped, and a pointer to
+ * the mapped range is held in gsi->virt_raw.  The inter-EE interrupt
+ * registers are accessed using that pointer.
+ *
+ * Most registers are accessed using gsi->virt, which is a copy of the "raw"
+ * pointer, adjusted downward by the fixed amount.
+ */
+#define GSI_EE_REG_ADJUST	0x0000d000			/* IPA v4.5+ */
+
+/* Sets gsi->virt_raw and gsi->virt, and I/O maps the "gsi" memory range */
+int gsi_reg_init(struct gsi *gsi, struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	resource_size_t size;
+	u32 adjust;
+
+	/* Get GSI memory range and map it */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gsi");
+	if (!res) {
+		dev_err(dev, "DT error getting \"gsi\" memory property\n");
+		return -ENODEV;
+	}
+
+	size = resource_size(res);
+	if (res->start > U32_MAX || size > U32_MAX - res->start) {
+		dev_err(dev, "DT memory resource \"gsi\" out of range\n");
+		return -EINVAL;
+	}
+
+	/* Make sure we can make our pointer adjustment if necessary */
+	adjust = gsi->version < IPA_VERSION_4_5 ? 0 : GSI_EE_REG_ADJUST;
+	if (res->start < adjust) {
+		dev_err(dev, "DT memory resource \"gsi\" too low (< %u)\n",
+			adjust);
+		return -EINVAL;
+	}
+
+	gsi->virt_raw = ioremap(res->start, size);
+	if (!gsi->virt_raw) {
+		dev_err(dev, "unable to remap \"gsi\" memory\n");
+		return -ENOMEM;
+	}
+	/* Most registers are accessed using an adjusted register range */
+	gsi->virt = gsi->virt_raw - adjust;
+
+	return 0;
+}
+
+/* Inverse of gsi_reg_init() */
+void gsi_reg_exit(struct gsi *gsi)
+{
+	gsi->virt = NULL;
+	iounmap(gsi->virt_raw);
+	gsi->virt_raw = NULL;
+}

drivers/net/ipa/gsi_reg.h

 /* SPDX-License-Identifier: GPL-2.0 */
 
 /* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
- * Copyright (C) 2018-2022 Linaro Ltd.
+ * Copyright (C) 2018-2023 Linaro Ltd.
  */
 #ifndef _GSI_REG_H_
 #define _GSI_REG_H_
 
-/* === Only "gsi.c" should include this file === */
+/* === Only "gsi.c" and "gsi_reg.c" should include this file === */
 
 #include <linux/bits.h>
 
@@ -38,20 +38,6 @@
  * (though the actual limit is hardware-dependent).
  */
 
-/* GSI EE registers as a group are shifted downward by a fixed constant amount
- * for IPA versions 4.5 and beyond.  This applies to all GSI registers we use
- * *except* the ones that disable inter-EE interrupts for channels and event
- * channels.
- *
- * The "raw" (not adjusted) GSI register range is mapped, and a pointer to
- * the mapped range is held in gsi->virt_raw.  The inter-EE interrupt
- * registers are accessed using that pointer.
- *
- * Most registers are accessed using gsi->virt, which is a copy of the "raw"
- * pointer, adjusted downward by the fixed amount.
- */
-#define GSI_EE_REG_ADJUST			0x0000d000	/* IPA v4.5+ */
-
 /* The inter-EE IRQ registers are relative to gsi->virt_raw (IPA v3.5+) */
 
 #define GSI_INTER_EE_SRC_CH_IRQ_MSK_OFFSET \
@@ -400,4 +386,21 @@ enum gsi_generic_ee_result {
 	GENERIC_EE_NO_RESOURCES			= 0x7,
 };
 
+/**
+ * gsi_reg_init() - Perform GSI register initialization
+ * @gsi:	GSI pointer
+ * @pdev:	GSI (IPA) platform device
+ *
+ * Initialize GSI registers, including looking up and I/O mapping
+ * the "gsi" memory space.  This function sets gsi->virt_raw and
+ * gsi->virt.
+ */
+int gsi_reg_init(struct gsi *gsi, struct platform_device *pdev);
+
+/**
+ * gsi_reg_exit() - Inverse of gsi_reg_init()
+ * @gsi:	GSI pointer
+ */
+void gsi_reg_exit(struct gsi *gsi);
+
 #endif	/* _GSI_REG_H_ */