hw/misc: Implement mailbox properties for customer OTP and device specific private keys

Four mailbox properties are implemented as follows:
1. Customer OTP: GET_CUSTOMER_OTP and SET_CUSTOMER_OTP
2. Device-specific private key: GET_PRIVATE_KEY and
SET_PRIVATE_KEY.

The customer OTP is located in the rows 36-43. The device-specific private key
is located in the rows 56-63.

The customer OTP can be locked with the magic numbers 0xffffffff 0xaffe0000
when running the SET_CUSTOMER_OTP mailbox command. Bit 6 of row 32 indicates
this lock, which is undocumented. The lock also applies to the device-specific
private key.

Signed-off-by: Rayhan Faizel <rayhan.faizel@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/bcm2835_peripherals.c

@@ -132,6 +132,8 @@ static void raspi_peripherals_base_init(Object *obj)
                                    OBJECT(&s->fb));
     object_property_add_const_link(OBJECT(&s->property), "dma-mr",
                                    OBJECT(&s->gpu_bus_mr));
+    object_property_add_const_link(OBJECT(&s->property), "otp",
+                                   OBJECT(&s->otp));
 
     /* Extended Mass Media Controller */
     object_initialize_child(obj, "sdhci", &s->sdhci, TYPE_SYSBUS_SDHCI);

hw/misc/bcm2835_property.c

@@ -32,6 +32,7 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
     uint32_t tmp;
     int n;
     uint32_t offset, length, color;
+    uint32_t start_num, number, otp_row;
 
     /*
      * Copy the current state of the framebuffer config; we will update
@@ -322,6 +323,89 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
                         0);
             resplen = VCHI_BUSADDR_SIZE;
             break;
+
+        /* Customer OTP */
+
+        case RPI_FWREQ_GET_CUSTOMER_OTP:
+            start_num = ldl_le_phys(&s->dma_as, value + 12);
+            number = ldl_le_phys(&s->dma_as, value + 16);
+
+            resplen = 8 + 4 * number;
+
+            for (n = start_num; n < start_num + number &&
+                 n < BCM2835_OTP_CUSTOMER_OTP_LEN; n++) {
+                otp_row = bcm2835_otp_get_row(s->otp,
+                                              BCM2835_OTP_CUSTOMER_OTP + n);
+                stl_le_phys(&s->dma_as,
+                            value + 20 + ((n - start_num) << 2), otp_row);
+            }
+            break;
+        case RPI_FWREQ_SET_CUSTOMER_OTP:
+            start_num = ldl_le_phys(&s->dma_as, value + 12);
+            number = ldl_le_phys(&s->dma_as, value + 16);
+
+            resplen = 4;
+
+            /* Magic numbers to permanently lock customer OTP */
+            if (start_num == BCM2835_OTP_LOCK_NUM1 &&
+                number == BCM2835_OTP_LOCK_NUM2) {
+                bcm2835_otp_set_row(s->otp,
+                                    BCM2835_OTP_ROW_32,
+                                    BCM2835_OTP_ROW_32_LOCK);
+                break;
+            }
+
+            /* If row 32 has the lock bit, don't allow further writes */
+            if (bcm2835_otp_get_row(s->otp, BCM2835_OTP_ROW_32) &
+                                    BCM2835_OTP_ROW_32_LOCK) {
+                break;
+            }
+
+            for (n = start_num; n < start_num + number &&
+                 n < BCM2835_OTP_CUSTOMER_OTP_LEN; n++) {
+                otp_row = ldl_le_phys(&s->dma_as,
+                                      value + 20 + ((n - start_num) << 2));
+                bcm2835_otp_set_row(s->otp,
+                                    BCM2835_OTP_CUSTOMER_OTP + n, otp_row);
+            }
+            break;
+
+        /* Device-specific private key */
+
+        case RPI_FWREQ_GET_PRIVATE_KEY:
+            start_num = ldl_le_phys(&s->dma_as, value + 12);
+            number = ldl_le_phys(&s->dma_as, value + 16);
+
+            resplen = 8 + 4 * number;
+
+            for (n = start_num; n < start_num + number &&
+                 n < BCM2835_OTP_PRIVATE_KEY_LEN; n++) {
+                otp_row = bcm2835_otp_get_row(s->otp,
+                                              BCM2835_OTP_PRIVATE_KEY + n);
+                stl_le_phys(&s->dma_as,
+                            value + 20 + ((n - start_num) << 2), otp_row);
+            }
+            break;
+        case RPI_FWREQ_SET_PRIVATE_KEY:
+            start_num = ldl_le_phys(&s->dma_as, value + 12);
+            number = ldl_le_phys(&s->dma_as, value + 16);
+
+            resplen = 4;
+
+            /* If row 32 has the lock bit, don't allow further writes */
+            if (bcm2835_otp_get_row(s->otp, BCM2835_OTP_ROW_32) &
+                                    BCM2835_OTP_ROW_32_LOCK) {
+                break;
+            }
+
+            for (n = start_num; n < start_num + number &&
+                 n < BCM2835_OTP_PRIVATE_KEY_LEN; n++) {
+                otp_row = ldl_le_phys(&s->dma_as,
+                                      value + 20 + ((n - start_num) << 2));
+                bcm2835_otp_set_row(s->otp,
+                                    BCM2835_OTP_PRIVATE_KEY + n, otp_row);
+            }
+            break;
         default:
             qemu_log_mask(LOG_UNIMP,
                           "bcm2835_property: unhandled tag 0x%08x\n", tag);
@@ -449,6 +533,9 @@ static void bcm2835_property_realize(DeviceState *dev, Error **errp)
     s->dma_mr = MEMORY_REGION(obj);
     address_space_init(&s->dma_as, s->dma_mr, TYPE_BCM2835_PROPERTY "-memory");
 
+    obj = object_property_get_link(OBJECT(dev), "otp", &error_abort);
+    s->otp = BCM2835_OTP(obj);
+
     /* TODO: connect to MAC address of USB NIC device, once we emulate it */
     qemu_macaddr_default_if_unset(&s->macaddr);
 

include/hw/arm/raspberrypi-fw-defs.h

@@ -56,6 +56,7 @@ enum rpi_firmware_property_tag {
     RPI_FWREQ_GET_THROTTLED =                          0x00030046,
     RPI_FWREQ_GET_CLOCK_MEASURED =                     0x00030047,
     RPI_FWREQ_NOTIFY_REBOOT =                          0x00030048,
+    RPI_FWREQ_GET_PRIVATE_KEY =                        0x00030081,
     RPI_FWREQ_SET_CLOCK_STATE =                        0x00038001,
     RPI_FWREQ_SET_CLOCK_RATE =                         0x00038002,
     RPI_FWREQ_SET_VOLTAGE =                            0x00038003,
@@ -73,6 +74,7 @@ enum rpi_firmware_property_tag {
     RPI_FWREQ_SET_PERIPH_REG =                         0x00038045,
     RPI_FWREQ_GET_POE_HAT_VAL =                        0x00030049,
     RPI_FWREQ_SET_POE_HAT_VAL =                        0x00038049,
+    RPI_FWREQ_SET_PRIVATE_KEY =                        0x00038081,
     RPI_FWREQ_SET_POE_HAT_VAL_OLD =                    0x00030050,
     RPI_FWREQ_NOTIFY_XHCI_RESET =                      0x00030058,
     RPI_FWREQ_GET_REBOOT_FLAGS =                       0x00030064,

include/hw/misc/bcm2835_property.h

@@ -11,6 +11,7 @@
 #include "hw/sysbus.h"
 #include "net/net.h"
 #include "hw/display/bcm2835_fb.h"
+#include "hw/nvram/bcm2835_otp.h"
 #include "qom/object.h"
 
 #define TYPE_BCM2835_PROPERTY "bcm2835-property"
@@ -26,6 +27,7 @@ struct BCM2835PropertyState {
     MemoryRegion iomem;
     qemu_irq mbox_irq;
     BCM2835FBState *fbdev;
+    BCM2835OTPState *otp;
 
     MACAddr macaddr;
     uint32_t board_rev;