[dwgpio] Add driver for the DesignWare GPIO controller

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/Makefile

@@ -83,6 +83,7 @@ SRCDIRS		+= drivers/net/marvell
 SRCDIRS		+= drivers/block
 SRCDIRS		+= drivers/nvs
 SRCDIRS		+= drivers/bitbash
+SRCDIRS		+= drivers/gpio
 SRCDIRS		+= drivers/infiniband
 SRCDIRS		+= drivers/infiniband/mlx_utils_flexboot/src
 SRCDIRS		+= drivers/infiniband/mlx_utils/src/public

src/drivers/bus/devtree.c

@@ -40,8 +40,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 static struct dt_driver dt_node_driver __dt_driver;
 
-static void dt_remove_children ( struct dt_device *parent );
-
 /**
  * Map devicetree range
  *
@@ -267,8 +265,7 @@ void dt_remove_node ( struct device *parent ) {
  * @v offset		Starting node offset
  * @ret rc		Return status code
  */
-static int dt_probe_children ( struct dt_device *parent,
-			       unsigned int offset ) {
+int dt_probe_children ( struct dt_device *parent, unsigned int offset ) {
 	struct fdt_descriptor desc;
 	int depth;
 	int rc;
@@ -314,7 +311,7 @@ static int dt_probe_children ( struct dt_device *parent,
  *
  * @v parent		Parent device
  */
-static void dt_remove_children ( struct dt_device *parent ) {
+void dt_remove_children ( struct dt_device *parent ) {
 
 	/* Remove all child nodes */
 	while ( ! list_empty ( &parent->dev.children ) )

src/drivers/gpio/dwgpio.c

@@ -0,0 +1,337 @@
+/*
+ * Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <ipxe/devtree.h>
+#include <ipxe/fdt.h>
+#include <ipxe/gpio.h>
+#include "dwgpio.h"
+
+/** @file
+ *
+ * Synopsys DesignWare GPIO driver
+ *
+ */
+
+/******************************************************************************
+ *
+ * GPIO port group
+ *
+ ******************************************************************************
+ */
+
+/**
+ * Probe port group
+ *
+ * @v dt		Devicetree device
+ * @v offset		Starting node offset
+ * @ret rc		Return status code
+ */
+static int dwgpio_group_probe ( struct dt_device *dt, unsigned int offset ) {
+	struct dwgpio_group *group;
+	int rc;
+
+	/* Allocate and initialise structure */
+	group = zalloc ( sizeof ( *group ) );
+	if ( ! group ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+	dt_set_drvdata ( dt, group );
+
+	/* Map registers */
+	group->base = dt_ioremap ( dt, offset, 0, 0 );
+	if ( ! group->base ) {
+		rc = -ENODEV;
+		goto err_ioremap;
+	}
+
+	/* Get region cell size specification */
+	fdt_reg_cells ( &sysfdt, offset, &group->regs );
+
+	/* Probe child ports */
+	if ( ( rc = dt_probe_children ( dt, offset ) ) != 0 )
+		goto err_children;
+
+	return 0;
+
+	dt_remove_children ( dt );
+ err_children:
+	iounmap ( group->base );
+ err_ioremap:
+	free ( group );
+ err_alloc:
+	return rc;
+}
+
+/**
+ * Remove port group
+ *
+ * @v dt		Devicetree device
+ */
+static void dwgpio_group_remove ( struct dt_device *dt ) {
+	struct dwgpio_group *group = dt_get_drvdata ( dt );
+
+	/* Remove child ports */
+	dt_remove_children ( dt );
+
+	/* Unmap registers */
+	iounmap ( group->base );
+
+	/* Free device */
+	free ( group );
+}
+
+/** DesignWare GPIO port group compatible model identifiers */
+static const char * dwgpio_group_ids[] = {
+	"snps,dw-apb-gpio",
+};
+
+/** DesignWare GPIO port group devicetree driver */
+struct dt_driver dwgpio_group_driver __dt_driver = {
+	.name = "dwgpio-group",
+	.ids = dwgpio_group_ids,
+	.id_count = ( sizeof ( dwgpio_group_ids ) /
+		      sizeof ( dwgpio_group_ids[0] ) ),
+	.probe = dwgpio_group_probe,
+	.remove = dwgpio_group_remove,
+};
+
+/******************************************************************************
+ *
+ * GPIO port
+ *
+ ******************************************************************************
+ */
+
+/**
+ * Dump GPIO port status
+ *
+ * @v dwgpio		DesignWare GPIO port
+ */
+static inline void dwgpio_dump ( struct dwgpio *dwgpio ) {
+
+	DBGC2 ( dwgpio, "DWGPIO %s dr %#08x ddr %#08x ctl %#08x\n",
+		dwgpio->name, readl ( dwgpio->swport + DWGPIO_SWPORT_DR ),
+		readl ( dwgpio->swport + DWGPIO_SWPORT_DDR ),
+		readl ( dwgpio->swport + DWGPIO_SWPORT_CTL ) );
+}
+
+/**
+ * Get current GPIO input value
+ *
+ * @v gpios		GPIO controller
+ * @v gpio		GPIO pin
+ * @ret active		Pin is in the active state
+ */
+static int dwgpio_in ( struct gpios *gpios, struct gpio *gpio ) {
+	struct dwgpio *dwgpio = gpios->priv;
+	uint32_t ext;
+
+	/* Read external port status */
+	ext = readl ( dwgpio->ext );
+	return ( ( ( ext >> gpio->index ) ^ gpio->config ) & 1 );
+}
+
+/**
+ * Set current GPIO output value
+ *
+ * @v gpios		GPIO controller
+ * @v gpio		GPIO pin
+ * @v active		Set pin to active state
+ */
+static void dwgpio_out ( struct gpios *gpios, struct gpio *gpio, int active ) {
+	struct dwgpio *dwgpio = gpios->priv;
+	uint32_t mask = ( 1UL << gpio->index );
+	uint32_t dr;
+
+	/* Update data register */
+	dr = readl ( dwgpio->swport + DWGPIO_SWPORT_DR );
+	dr &= ~mask;
+	if ( ( ( !! active ) ^ gpio->config ) & 1 )
+		dr |= mask;
+	writel ( dr, ( dwgpio->swport + DWGPIO_SWPORT_DR ) );
+	dwgpio_dump ( dwgpio );
+}
+
+/**
+ * Configure GPIO pin
+ *
+ * @v gpios		GPIO controller
+ * @v gpio		GPIO pin
+ * @v config		Configuration
+ * @ret rc		Return status code
+ */
+static int dwgpio_config ( struct gpios *gpios, struct gpio *gpio,
+			   unsigned int config ) {
+	struct dwgpio *dwgpio = gpios->priv;
+	uint32_t mask = ( 1UL << gpio->index );
+	uint32_t ddr;
+	uint32_t ctl;
+
+	/* Update data direction and control registers */
+	ddr = readl ( dwgpio->swport + DWGPIO_SWPORT_DDR );
+	ctl = readl ( dwgpio->swport + DWGPIO_SWPORT_CTL );
+	ctl &= ~mask;
+	ddr &= ~mask;
+	if ( config & GPIO_CFG_OUTPUT )
+		ddr |= mask;
+	writel ( ctl, ( dwgpio->swport + DWGPIO_SWPORT_CTL ) );
+	writel ( ddr, ( dwgpio->swport + DWGPIO_SWPORT_DDR ) );
+	dwgpio_dump ( dwgpio );
+
+	return 0;
+}
+
+/** GPIO operations */
+static struct gpio_operations dwgpio_operations = {
+	.in = dwgpio_in,
+	.out = dwgpio_out,
+	.config = dwgpio_config,
+};
+
+/**
+ * Probe port
+ *
+ * @v dt		Devicetree device
+ * @v offset		Starting node offset
+ * @ret rc		Return status code
+ */
+static int dwgpio_probe ( struct dt_device *dt, unsigned int offset ) {
+	struct dt_device *parent;
+	struct dwgpio_group *group;
+	struct dwgpio *dwgpio;
+	struct gpios *gpios;
+	uint32_t count;
+	uint64_t port;
+	int rc;
+
+	/* Get number of GPIOs */
+	if ( ( rc = fdt_u32 ( &sysfdt, offset, "nr-gpios-snps",
+			      &count ) ) != 0 ) {
+		goto err_count;
+	}
+	assert ( count <= DWGPIO_MAX_COUNT );
+
+	/* Allocate and initialise device */
+	gpios = alloc_gpios ( count, sizeof ( *dwgpio ) );
+	if ( ! gpios ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+	dt_set_drvdata ( dt, gpios );
+	gpios->dev = &dt->dev;
+	gpios_init ( gpios, &dwgpio_operations );
+	dwgpio = gpios->priv;
+	dwgpio->name = dt->name;
+
+	/* Identify group */
+	parent = dt_parent ( dt );
+	if ( parent->driver != &dwgpio_group_driver ) {
+		DBGC ( dwgpio, "DWGPIO %s has invalid parent %s\n",
+		       dwgpio->name, parent->name );
+		rc = -EINVAL;
+		goto err_parent;
+	}
+	group = dt_get_drvdata ( parent );
+
+	/* Identify port */
+	if ( ( rc = fdt_reg_address ( &sysfdt, offset, &group->regs, 0,
+				      &port ) ) != 0 ) {
+		DBGC ( dwgpio, "DWGPIO %s could not get port number: %s\n",
+		       dwgpio->name, strerror ( rc ) );
+		goto err_port;
+	}
+	dwgpio->port = port;
+	DBGC ( dwgpio, "DWGPIO %s is %s port %d (%d GPIOs)\n",
+	       dwgpio->name, parent->name, dwgpio->port, gpios->count );
+
+	/* Map registers */
+	dwgpio->swport = ( group->base + DWGPIO_SWPORT ( port ) );
+	dwgpio->ext = ( group->base + DWGPIO_EXT_PORT ( port ) );
+	dwgpio_dump ( dwgpio );
+
+	/* Record original register values */
+	dwgpio->dr = readl ( dwgpio->swport + DWGPIO_SWPORT_DR );
+	dwgpio->ddr = readl ( dwgpio->swport + DWGPIO_SWPORT_DDR );
+	dwgpio->ctl = readl ( dwgpio->swport + DWGPIO_SWPORT_CTL );
+
+	/* Register GPIO controller */
+	if ( ( rc = gpios_register ( gpios ) ) != 0 ) {
+		DBGC ( dwgpio, "DWGPIO %s could not register: %s\n",
+		       dwgpio->name, strerror ( rc ) );
+		goto err_register;
+	}
+
+	return 0;
+
+	gpios_unregister ( gpios );
+ err_register:
+ err_port:
+ err_parent:
+	gpios_nullify ( gpios );
+	gpios_put ( gpios );
+ err_alloc:
+ err_count:
+	return rc;
+}
+
+/**
+ * Remove port
+ *
+ * @v dt		Devicetree device
+ */
+static void dwgpio_remove ( struct dt_device *dt ) {
+	struct gpios *gpios = dt_get_drvdata ( dt );
+	struct dwgpio *dwgpio = gpios->priv;
+
+	/* Unregister GPIO controller */
+	gpios_unregister ( gpios );
+
+	/* Restore original register values */
+	writel ( dwgpio->ctl, ( dwgpio->swport + DWGPIO_SWPORT_CTL ) );
+	writel ( dwgpio->ddr, ( dwgpio->swport + DWGPIO_SWPORT_DDR ) );
+	writel ( dwgpio->dr, ( dwgpio->swport + DWGPIO_SWPORT_DR ) );
+
+	/* Free GPIO device */
+	gpios_nullify ( gpios );
+	gpios_put ( gpios );
+}
+
+/** DesignWare GPIO port compatible model identifiers */
+static const char * dwgpio_ids[] = {
+	"snps,dw-apb-gpio-port",
+};
+
+/** DesignWare GPIO port devicetree driver */
+struct dt_driver dwgpio_driver __dt_driver = {
+	.name = "dwgpio",
+	.ids = dwgpio_ids,
+	.id_count = ( sizeof ( dwgpio_ids ) / sizeof ( dwgpio_ids[0] ) ),
+	.probe = dwgpio_probe,
+	.remove = dwgpio_remove,
+};

src/drivers/gpio/dwgpio.h

@@ -0,0 +1,81 @@
+#ifndef _DWGPIO_H
+#define _DWGPIO_H
+
+/** @file
+ *
+ * Synopsys DesignWare GPIO driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** Maximum number of GPIOs per port */
+#define DWGPIO_MAX_COUNT 32
+
+/** Software port
+ *
+ * This is the register bank containing the DR, DDR, and CTL bits.
+ */
+#define DWGPIO_SWPORT( x ) ( 0x00 + ( (x) * 0x0c ) )
+
+/** Data register
+ *
+ * Bits written to this register are output if the corresponding DDR
+ * bit is set to 1 (output) and the corresponding CTL bit is set to 0
+ * (software control).
+ *
+ * Bits read from this register reflect the most recently written
+ * value, and do not reflect the actual status of the GPIO pin.
+ */
+#define DWGPIO_SWPORT_DR 0x00
+
+/** Data direction register
+ *
+ * The GPIO is an output if the corresponding bit in this register is
+ * set to 1.
+ */
+#define DWGPIO_SWPORT_DDR 0x04
+
+/** Control register
+ *
+ * The GPIO is under software control (i.e. is functioning as a GPIO,
+ * rather than being controlled by a separate functional block) if the
+ * corresponding bit in this register is set to 0.
+ */
+#define DWGPIO_SWPORT_CTL 0x08
+
+/** External port
+ *
+ * Bits read from this register reflect the current status of the GPIO
+ * pin.
+ */
+#define DWGPIO_EXT_PORT( x ) ( 0x50 + ( (x) * 0x04 ) )
+
+/** A DesignWare GPIO port group */
+struct dwgpio_group {
+	/** Register base */
+	void *base;
+	/** Region cell size specification */
+	struct fdt_reg_cells regs;
+};
+
+/** A DesignWare GPIO port */
+struct dwgpio {
+	/** Device name */
+	const char *name;
+	/** Port index */
+	unsigned int port;
+	/** Software port registers */
+	void *swport;
+	/** External port register */
+	void *ext;
+
+	/** Original data register value */
+	uint32_t dr;
+	/** Original data direction register value */
+	uint32_t ddr;
+	/** Original control register value */
+	uint32_t ctl;
+};
+
+#endif /* _DWGPIO_H */

src/include/ipxe/devtree.h

@@ -77,9 +77,21 @@ static inline void * dt_get_drvdata ( struct dt_device *dt ) {
 	return dt->priv;
 }
 
+/**
+ * Get devicetree parent device
+ *
+ * @v dt		Devicetree device
+ * @ret parent		Parent devicetree device
+ */
+static inline struct dt_device * dt_parent ( struct dt_device *dt ) {
+	return container_of ( dt->dev.parent, struct dt_device, dev );
+}
+
 extern void * dt_ioremap ( struct dt_device *dt, unsigned int offset,
 			   unsigned int index, size_t len );
 extern int dt_probe_node ( struct device *parent, unsigned int offset );
 extern void dt_remove_node ( struct device *parent );
+extern int dt_probe_children ( struct dt_device *parent, unsigned int offset );
+extern void dt_remove_children ( struct dt_device *parent );
 
 #endif /* _IPXE_DEVTREE_H */

src/include/ipxe/errfile.h

@@ -239,6 +239,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_cgem		     ( ERRFILE_DRIVER | 0x00db0000 )
 #define ERRFILE_dwmac		     ( ERRFILE_DRIVER | 0x00dc0000 )
 #define ERRFILE_dwusb		     ( ERRFILE_DRIVER | 0x00dd0000 )
+#define ERRFILE_dwgpio		     ( ERRFILE_DRIVER | 0x00de0000 )
 
 #define ERRFILE_aoe			( ERRFILE_NET | 0x00000000 )
 #define ERRFILE_arp			( ERRFILE_NET | 0x00010000 )