sm501: Implement i2c part for reading monitor EDID

Emulate the i2c part of SM501 which is used to access the EDID info
from a monitor.

The vmstate structure is changed and its version is increased but
SM501 is only used on SH and PPC sam460ex machines that don't support
cross-version migration.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 143 insertions, 4 deletions

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index 9dec0d3..05c964b 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -26,6 +26,7 @@
 #include "qemu/osdep.h"
 #include "qemu/units.h"
 #include "qapi/error.h"
+#include "qemu/log.h"
 #include "qemu-common.h"
 #include "cpu.h"
 #include "hw/hw.h"
@@ -34,6 +35,8 @@
 #include "hw/devices.h"
 #include "hw/sysbus.h"
 #include "hw/pci/pci.h"
+#include "hw/i2c/i2c.h"
+#include "hw/i2c/i2c-ddc.h"
 #include "qemu/range.h"
 #include "ui/pixel_ops.h"
 
@@ -216,6 +219,14 @@
 #define SM501_I2C_SLAVE_ADDRESS         (0x03)
 #define SM501_I2C_DATA                  (0x04)
 
+#define SM501_I2C_CONTROL_START         (1 << 2)
+#define SM501_I2C_CONTROL_ENABLE        (1 << 0)
+
+#define SM501_I2C_STATUS_COMPLETE       (1 << 3)
+#define SM501_I2C_STATUS_ERROR          (1 << 2)
+
+#define SM501_I2C_RESET_ERROR           (1 << 2)
+
 /* SSP base */
 #define SM501_SSP                       (0x020000)
 
@@ -471,10 +482,12 @@ typedef struct SM501State {
     MemoryRegion local_mem_region;
     MemoryRegion mmio_region;
     MemoryRegion system_config_region;
+    MemoryRegion i2c_region;
     MemoryRegion disp_ctrl_region;
     MemoryRegion twoD_engine_region;
     uint32_t last_width;
     uint32_t last_height;
+    I2CBus *i2c_bus;
 
     /* mmio registers */
     uint32_t system_control;
@@ -487,6 +500,11 @@ typedef struct SM501State {
     uint32_t misc_timing;
     uint32_t power_mode_control;
 
+    uint8_t i2c_byte_count;
+    uint8_t i2c_status;
+    uint8_t i2c_addr;
+    uint8_t i2c_data[16];
+
     uint32_t uart0_ier;
     uint32_t uart0_lcr;
     uint32_t uart0_mcr;
@@ -897,6 +915,109 @@ static const MemoryRegionOps sm501_system_config_ops = {
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
+static uint64_t sm501_i2c_read(void *opaque, hwaddr addr, unsigned size)
+{
+    SM501State *s = (SM501State *)opaque;
+    uint8_t ret = 0;
+
+    switch (addr) {
+    case SM501_I2C_BYTE_COUNT:
+        ret = s->i2c_byte_count;
+        break;
+    case SM501_I2C_STATUS:
+        ret = s->i2c_status;
+        break;
+    case SM501_I2C_SLAVE_ADDRESS:
+        ret = s->i2c_addr;
+        break;
+    case SM501_I2C_DATA ... SM501_I2C_DATA + 15:
+        ret = s->i2c_data[addr - SM501_I2C_DATA];
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "sm501 i2c : not implemented register read."
+                      " addr=0x%" HWADDR_PRIx "\n", addr);
+    }
+
+    SM501_DPRINTF("sm501 i2c regs : read addr=%" HWADDR_PRIx " val=%x\n",
+                  addr, ret);
+    return ret;
+}
+
+static void sm501_i2c_write(void *opaque, hwaddr addr, uint64_t value,
+                            unsigned size)
+{
+    SM501State *s = (SM501State *)opaque;
+    SM501_DPRINTF("sm501 i2c regs : write addr=%" HWADDR_PRIx
+                  " val=%" PRIx64 "\n", addr, value);
+
+    switch (addr) {
+    case SM501_I2C_BYTE_COUNT:
+        s->i2c_byte_count = value & 0xf;
+        break;
+    case SM501_I2C_CONTROL:
+        if (value & SM501_I2C_CONTROL_ENABLE) {
+            if (value & SM501_I2C_CONTROL_START) {
+                int res = i2c_start_transfer(s->i2c_bus,
+                                             s->i2c_addr >> 1,
+                                             s->i2c_addr & 1);
+                s->i2c_status |= (res ? SM501_I2C_STATUS_ERROR : 0);
+                if (!res) {
+                    int i;
+                    SM501_DPRINTF("sm501 i2c : transferring %d bytes to 0x%x\n",
+                                  s->i2c_byte_count + 1, s->i2c_addr >> 1);
+                    for (i = 0; i <= s->i2c_byte_count; i++) {
+                        res = i2c_send_recv(s->i2c_bus, &s->i2c_data[i],
+                                            !(s->i2c_addr & 1));
+                        if (res) {
+                            SM501_DPRINTF("sm501 i2c : transfer failed"
+                                          " i=%d, res=%d\n", i, res);
+                            s->i2c_status |= (res ? SM501_I2C_STATUS_ERROR : 0);
+                            return;
+                        }
+                    }
+                    if (i) {
+                        SM501_DPRINTF("sm501 i2c : transferred %d bytes\n", i);
+                        s->i2c_status = SM501_I2C_STATUS_COMPLETE;
+                    }
+                }
+            } else {
+                SM501_DPRINTF("sm501 i2c : end transfer\n");
+                i2c_end_transfer(s->i2c_bus);
+                s->i2c_status &= ~SM501_I2C_STATUS_ERROR;
+            }
+        }
+        break;
+    case SM501_I2C_RESET:
+        if ((value & SM501_I2C_RESET_ERROR) == 0) {
+            s->i2c_status &= ~SM501_I2C_STATUS_ERROR;
+        }
+        break;
+    case SM501_I2C_SLAVE_ADDRESS:
+        s->i2c_addr = value & 0xff;
+        break;
+    case SM501_I2C_DATA ... SM501_I2C_DATA + 15:
+        s->i2c_data[addr - SM501_I2C_DATA] = value & 0xff;
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "sm501 i2c : not implemented register write. "
+                      "addr=0x%" HWADDR_PRIx " val=%" PRIx64 "\n", addr, value);
+    }
+}
+
+static const MemoryRegionOps sm501_i2c_ops = {
+    .read = sm501_i2c_read,
+    .write = sm501_i2c_write,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
 static uint32_t sm501_palette_read(void *opaque, hwaddr addr)
 {
     SM501State *s = (SM501State *)opaque;
@@ -1577,6 +1698,10 @@ static void sm501_reset(SM501State *s)
     s->irq_mask = 0;
     s->misc_timing = 0;
     s->power_mode_control = 0;
+    s->i2c_byte_count = 0;
+    s->i2c_status = 0;
+    s->i2c_addr = 0;
+    memset(s->i2c_data, 0, 16);
     s->dc_panel_control = 0x00010000; /* FIFO level 3 */
     s->dc_video_control = 0;
     s->dc_crt_control = 0x00010000;
@@ -1615,6 +1740,12 @@ static void sm501_init(SM501State *s, DeviceState *dev,
     memory_region_set_log(&s->local_mem_region, true, DIRTY_MEMORY_VGA);
     s->local_mem = memory_region_get_ram_ptr(&s->local_mem_region);
 
+    /* i2c */
+    s->i2c_bus = i2c_init_bus(dev, "sm501.i2c");
+    /* ddc */
+    I2CDDCState *ddc = I2CDDC(qdev_create(BUS(s->i2c_bus), TYPE_I2CDDC));
+    i2c_set_slave_address(I2C_SLAVE(ddc), 0x50);
+
     /* mmio */
     memory_region_init(&s->mmio_region, OBJECT(dev), "sm501.mmio", MMIO_SIZE);
     memory_region_init_io(&s->system_config_region, OBJECT(dev),
@@ -1622,6 +1753,9 @@ static void sm501_init(SM501State *s, DeviceState *dev,
                           "sm501-system-config", 0x6c);
     memory_region_add_subregion(&s->mmio_region, SM501_SYS_CONFIG,
                                 &s->system_config_region);
+    memory_region_init_io(&s->i2c_region, OBJECT(dev), &sm501_i2c_ops, s,
+                          "sm501-i2c", 0x14);
+    memory_region_add_subregion(&s->mmio_region, SM501_I2C, &s->i2c_region);
     memory_region_init_io(&s->disp_ctrl_region, OBJECT(dev),
                           &sm501_disp_ctrl_ops, s,
                           "sm501-disp-ctrl", 0x1000);
@@ -1705,6 +1839,11 @@ static const VMStateDescription vmstate_sm501_state = {
         VMSTATE_UINT32(twoD_destination_base, SM501State),
         VMSTATE_UINT32(twoD_alpha, SM501State),
         VMSTATE_UINT32(twoD_wrap, SM501State),
+        /* Added in version 2 */
+        VMSTATE_UINT8(i2c_byte_count, SM501State),
+        VMSTATE_UINT8(i2c_status, SM501State),
+        VMSTATE_UINT8(i2c_addr, SM501State),
+        VMSTATE_UINT8_ARRAY(i2c_data, SM501State, 16),
         VMSTATE_END_OF_LIST()
      }
 };
@@ -1770,8 +1909,8 @@ static void sm501_reset_sysbus(DeviceState *dev)
 
 static const VMStateDescription vmstate_sm501_sysbus = {
     .name = TYPE_SYSBUS_SM501,
-    .version_id = 1,
-    .minimum_version_id = 1,
+    .version_id = 2,
+    .minimum_version_id = 2,
     .fields = (VMStateField[]) {
         VMSTATE_STRUCT(state, SM501SysBusState, 1,
                        vmstate_sm501_state, SM501State),
@@ -1843,8 +1982,8 @@ static void sm501_reset_pci(DeviceState *dev)
 
 static const VMStateDescription vmstate_sm501_pci = {
     .name = TYPE_PCI_SM501,
-    .version_id = 1,
-    .minimum_version_id = 1,
+    .version_id = 2,
+    .minimum_version_id = 2,
     .fields = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(parent_obj, SM501PCIState),
         VMSTATE_STRUCT(state, SM501PCIState, 1,