diff options
| -rw-r--r-- | hw/net/smc91c111.c | 65 |
1 files changed, 53 insertions, 12 deletions
diff --git a/hw/net/smc91c111.c b/hw/net/smc91c111.c index b05970d5e1..9ce42b5615 100644 --- a/hw/net/smc91c111.c +++ b/hw/net/smc91c111.c @@ -13,6 +13,7 @@ #include "net/net.h" #include "hw/irq.h" #include "hw/net/smc91c111.h" +#include "hw/registerfields.h" #include "hw/qdev-properties.h" #include "qapi/error.h" #include "qemu/log.h" @@ -126,6 +127,13 @@ static const VMStateDescription vmstate_smc91c111 = { #define RS_TOOSHORT 0x0400 #define RS_MULTICAST 0x0001 +FIELD(PTR, PTR, 0, 11) +FIELD(PTR, NOT_EMPTY, 11, 1) +FIELD(PTR, RESERVED, 12, 1) +FIELD(PTR, READ, 13, 1) +FIELD(PTR, AUTOINCR, 14, 1) +FIELD(PTR, RCV, 15, 1) + static inline bool packetnum_valid(int packet_num) { return packet_num >= 0 && packet_num < NUM_PACKETS; @@ -372,6 +380,49 @@ static void smc91c111_reset(DeviceState *dev) #define SET_LOW(name, val) s->name = (s->name & 0xff00) | val #define SET_HIGH(name, val) s->name = (s->name & 0xff) | (val << 8) +/* + * The pointer register's pointer is an 11 bit value (so it exactly + * indexes a 2048-byte data frame). Add the specified offset to it, + * wrapping around at the 2048 byte mark, and return the resulting + * wrapped value. There are flag bits in the top part of the register, + * but we can ignore them here as the mask will mask them out. + */ +static int ptr_reg_add(smc91c111_state *s, int offset) +{ + return (s->ptr + offset) & R_PTR_PTR_MASK; +} + +/* + * For an access to the Data Register at @offset, return the + * required offset into the packet's data frame. This will + * perform the pointer register autoincrement if required, and + * guarantees to return an in-bounds offset. + */ +static int data_reg_ptr(smc91c111_state *s, int offset) +{ + int p; + + if (s->ptr & R_PTR_AUTOINCR_MASK) { + /* + * Autoincrement: use the current pointer value, and + * increment the pointer register's pointer field. + */ + p = FIELD_EX32(s->ptr, PTR, PTR); + s->ptr = FIELD_DP32(s->ptr, PTR, PTR, ptr_reg_add(s, 1)); + } else { + /* + * No autoincrement: register offset determines which + * byte we're addressing. Setting the pointer to the top + * of the data buffer and then using the pointer wrapping + * to read the bottom byte of the buffer is not something + * sensible guest software will do, but the datasheet + * doesn't say what the behaviour is, so we don't forbid it. + */ + p = ptr_reg_add(s, offset & 3); + } + return p; +} + static void smc91c111_writeb(void *opaque, hwaddr offset, uint32_t value) { @@ -518,12 +569,7 @@ static void smc91c111_writeb(void *opaque, hwaddr offset, n); return; } - p = s->ptr & 0x07ff; - if (s->ptr & 0x4000) { - s->ptr = (s->ptr & 0xf800) | ((s->ptr + 1) & 0x7ff); - } else { - p += (offset & 3); - } + p = data_reg_ptr(s, offset); s->data[n][p] = value; } return; @@ -673,12 +719,7 @@ static uint32_t smc91c111_readb(void *opaque, hwaddr offset) n); return 0; } - p = s->ptr & 0x07ff; - if (s->ptr & 0x4000) { - s->ptr = (s->ptr & 0xf800) | ((s->ptr + 1) & 0x07ff); - } else { - p += (offset & 3); - } + p = data_reg_ptr(s, offset); return s->data[n][p]; } case 12: /* Interrupt status. */ |