new file mode 100644
@@ -0,0 +1,43 @@
+/*
+ * Simple I2C peripheral for testing I2C device models.
+ *
+ * At the moment of introducing this not all of the functionality can be tested
+ * with an existing QEMU peripheral device, notably error paths such as when a
+ * peripheral device responds with an I2C_NACK during a transaction.
+ *
+ * It also provides a place where new future functionality can be added to help
+ * with more kinds of tests rather than trying to hack it in a real device where
+ * it might not even be possible.
+ *
+ * The peripheral allows reading and writing to a fixed number of registers.
+ * The first transmitted byte in a transaction sets the index register. Note
+ * that the index register is not auto-incremented on neither reads nor writes.
+ *
+ * Copyright (c) 2024 Google LLC
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef HW_I2C_TESTER_H
+#define HW_I2C_TESTER_H
+
+#include "qemu/osdep.h"
+#include "hw/i2c/i2c.h"
+#include "hw/irq.h"
+
+#define I2C_TESTER_NUM_REGS 0x31
+
+#define TYPE_I2C_TESTER "i2c-tester"
+#define I2C_TESTER(obj) OBJECT_CHECK(I2cTesterState, (obj), TYPE_I2C_TESTER)
+
+typedef struct {
+ I2CSlave i2c;
+ bool set_reg_idx;
+ uint8_t reg_idx;
+ uint8_t regs[I2C_TESTER_NUM_REGS];
+} I2cTesterState;
+
+#endif /* HW_I2C_TESTER_H */
new file mode 100644
@@ -0,0 +1,109 @@
+/*
+ * Simple I2C peripheral for testing I2C device models.
+ *
+ * Copyright (c) 2024 Google LLC
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "hw/misc/i2c_tester.h"
+
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "migration/vmstate.h"
+
+static void i2c_tester_reset_enter(Object *o, ResetType type)
+{
+ I2cTesterState *s = I2C_TESTER(o);
+
+ s->set_reg_idx = false;
+ s->reg_idx = 0;
+ memset(s->regs, 0, I2C_TESTER_NUM_REGS);
+}
+
+static int i2c_tester_event(I2CSlave *i2c, enum i2c_event event)
+{
+ I2cTesterState *s = I2C_TESTER(i2c);
+
+ if (event == I2C_START_SEND) {
+ s->set_reg_idx = true;
+ }
+
+ return 0;
+}
+
+static uint8_t i2c_tester_rx(I2CSlave *i2c)
+{
+ I2cTesterState *s = I2C_TESTER(i2c);
+
+ if (s->reg_idx >= I2C_TESTER_NUM_REGS) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid reg 0x%02x\n", __func__,
+ s->reg_idx);
+ return I2C_NACK;
+ }
+
+ return s->regs[s->reg_idx];
+}
+
+static int i2c_tester_tx(I2CSlave *i2c, uint8_t data)
+{
+ I2cTesterState *s = I2C_TESTER(i2c);
+
+ if (s->set_reg_idx) {
+ /* Setting the register in which the operation will be done. */
+ s->reg_idx = data;
+ s->set_reg_idx = false;
+ return 0;
+ }
+
+ if (s->reg_idx >= I2C_TESTER_NUM_REGS) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid reg 0x%02x\n", __func__,
+ s->reg_idx);
+ return I2C_NACK;
+ }
+
+ /* Write reg data. */
+ s->regs[s->reg_idx] = data;
+
+ return 0;
+}
+
+static const VMStateDescription vmstate_i2c_tester = {
+ .name = "i2c-tester",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (const VMStateField[]) {
+ VMSTATE_I2C_SLAVE(i2c, I2cTesterState),
+ VMSTATE_BOOL(set_reg_idx, I2cTesterState),
+ VMSTATE_UINT8(reg_idx, I2cTesterState),
+ VMSTATE_UINT8_ARRAY(regs, I2cTesterState, I2C_TESTER_NUM_REGS),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void i2c_tester_class_init(ObjectClass *oc, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(oc);
+ ResettableClass *rc = RESETTABLE_CLASS(oc);
+ I2CSlaveClass *isc = I2C_SLAVE_CLASS(oc);
+
+ rc->phases.enter = i2c_tester_reset_enter;
+ dc->vmsd = &vmstate_i2c_tester;
+ isc->event = i2c_tester_event;
+ isc->recv = i2c_tester_rx;
+ isc->send = i2c_tester_tx;
+}
+
+static const TypeInfo i2c_tester_types[] = {
+ {
+ .name = TYPE_I2C_TESTER,
+ .parent = TYPE_I2C_SLAVE,
+ .instance_size = sizeof(I2cTesterState),
+ .class_init = i2c_tester_class_init
+ },
+};
+
+DEFINE_TYPES(i2c_tester_types);
@@ -213,6 +213,11 @@ config IOSB
config XLNX_VERSAL_TRNG
bool
+config I2C_TESTER
+ bool
+ default y if TEST_DEVICES
+ depends on I2C
+
config FLEXCOMM
bool
select I2C
@@ -152,6 +152,8 @@ system_ss.add(when: 'CONFIG_SBSA_REF', if_true: files('sbsa_ec.c'))
# HPPA devices
system_ss.add(when: 'CONFIG_LASI', if_true: files('lasi.c'))
+system_ss.add(when: 'CONFIG_I2C_TESTER', if_true: files('i2c_tester.c'))
+
system_ss.add(when: 'CONFIG_FLEXCOMM', if_true: files('flexcomm.c'))
system_ss.add(when: 'CONFIG_RT500_CLKCTL', if_true: files('rt500_clkctl0.c', 'rt500_clkctl1.c'))
system_ss.add(when: 'CONFIG_RT500_RSTCTL', if_true: files('rt500_rstctl.c'))
Add a simple i2c peripheral to be used for testing I2C device models. The peripheral has a fixed number of registers that can be read and written. Signed-off-by: Octavian Purdila <tavip@google.com> --- include/hw/misc/i2c_tester.h | 43 ++++++++++++++ hw/misc/i2c_tester.c | 109 +++++++++++++++++++++++++++++++++++ hw/misc/Kconfig | 5 ++ hw/misc/meson.build | 2 + 4 files changed, 159 insertions(+) create mode 100644 include/hw/misc/i2c_tester.h create mode 100644 hw/misc/i2c_tester.c