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Re: [PATCH 3/4] dp8393x: Store CAM registers as 16-bit
From: |
Finn Thain |
Subject: |
Re: [PATCH 3/4] dp8393x: Store CAM registers as 16-bit |
Date: |
Wed, 7 Jul 2021 09:48:10 +1000 (AEST) |
On Mon, 5 Jul 2021, Mark Cave-Ayland wrote:
> From: Philippe Mathieu-Daudé <f4bug@amsat.org>
>
> Per the DP83932C datasheet from July 1995:
>
> 4.0 SONIC Registers
> 4.1 THE CAM UNIT
>
> The Content Addressable Memory (CAM) consists of sixteen
> 48-bit entries for complete address filtering of network
> packets. Each entry corresponds to a 48-bit destination
> address that is user programmable and can contain any
> combination of Multicast or Physical addresses. Each entry
> is partitioned into three 16-bit CAM cells accessible
> through CAM Address Ports (CAP 2, CAP 1 and CAP 0) with
> CAP0 corresponding to the least significant 16 bits of
> the Destination Address and CAP2 corresponding to the
> most significant bits.
>
> Store the CAM registers as 16-bit as it simplifies the code.
> There is no change in the migration stream.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> hw/net/dp8393x.c | 23 ++++++++++-------------
> 1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
> index cc7c001edb..22ceea338c 100644
> --- a/hw/net/dp8393x.c
> +++ b/hw/net/dp8393x.c
> @@ -157,7 +157,7 @@ struct dp8393xState {
> MemoryRegion mmio;
>
> /* Registers */
> - uint8_t cam[16][6];
> + uint16_t cam[16][3];
> uint16_t regs[0x40];
>
> /* Temporaries */
> @@ -280,15 +280,13 @@ static void dp8393x_do_load_cam(dp8393xState *s)
> address_space_read(&s->as, dp8393x_cdp(s),
> MEMTXATTRS_UNSPECIFIED, s->data, size);
> index = dp8393x_get(s, width, 0) & 0xf;
> - s->cam[index][0] = dp8393x_get(s, width, 1) & 0xff;
> - s->cam[index][1] = dp8393x_get(s, width, 1) >> 8;
> - s->cam[index][2] = dp8393x_get(s, width, 2) & 0xff;
> - s->cam[index][3] = dp8393x_get(s, width, 2) >> 8;
> - s->cam[index][4] = dp8393x_get(s, width, 3) & 0xff;
> - s->cam[index][5] = dp8393x_get(s, width, 3) >> 8;
> - trace_dp8393x_load_cam(index, s->cam[index][0], s->cam[index][1],
> - s->cam[index][2], s->cam[index][3],
> - s->cam[index][4], s->cam[index][5]);
> + s->cam[index][0] = dp8393x_get(s, width, 1);
> + s->cam[index][1] = dp8393x_get(s, width, 2);
> + s->cam[index][2] = dp8393x_get(s, width, 3);
> + trace_dp8393x_load_cam(index,
> + s->cam[index][0] >> 8, s->cam[index][0] &
> 0xff,
> + s->cam[index][1] >> 8, s->cam[index][1] &
> 0xff,
> + s->cam[index][2] >> 8, s->cam[index][2] &
> 0xff);
> /* Move to next entry */
> s->regs[SONIC_CDC]--;
> s->regs[SONIC_CDP] += size;
> @@ -591,8 +589,7 @@ static uint64_t dp8393x_read(void *opaque, hwaddr addr,
> unsigned int size)
> case SONIC_CAP1:
> case SONIC_CAP0:
> if (s->regs[SONIC_CR] & SONIC_CR_RST) {
> - val = s->cam[s->regs[SONIC_CEP] & 0xf][2 * (SONIC_CAP0 - reg) +
> 1] << 8;
> - val |= s->cam[s->regs[SONIC_CEP] & 0xf][2 * (SONIC_CAP0 - reg)];
> + val = s->cam[s->regs[SONIC_CEP] & 0xf][2 * (SONIC_CAP0 - reg)];
> }
> break;
> /* All other registers have no special contraints */
This patch incorrectly alters the behaviour of the jazzsonic.c driver
which reads the MAC address from the CAP registers in sonic_probe1().
With mainline QEMU, the driver reports:
SONIC ethernet @e0001000, MAC 00:00:00:44:33:22, IRQ 28
With this patch:
SONIC ethernet @e0001000, MAC 00:00:33:22:00:00, IRQ 28
> @@ -990,7 +987,7 @@ static const VMStateDescription vmstate_dp8393x = {
> .version_id = 0,
> .minimum_version_id = 0,
> .fields = (VMStateField []) {
> - VMSTATE_BUFFER_UNSAFE(cam, dp8393xState, 0, 16 * 6),
> + VMSTATE_BUFFER_UNSAFE(cam, dp8393xState, 0, 16 * 3 * 2),
> VMSTATE_UINT16_ARRAY(regs, dp8393xState, 0x40),
> VMSTATE_END_OF_LIST()
> }
>
- [PATCH 1/4] dp8393x: don't force 32-bit register access, (continued)
[PATCH 2/4] dp8393x: Replace address_space_rw(is_write=1) by address_space_write(), Mark Cave-Ayland, 2021/07/05
[PATCH 3/4] dp8393x: Store CAM registers as 16-bit, Mark Cave-Ayland, 2021/07/05
- Re: [PATCH 3/4] dp8393x: Store CAM registers as 16-bit,
Finn Thain <=
[PATCH 4/4] dp8393x: Rewrite dp8393x_get() / dp8393x_put(), Mark Cave-Ayland, 2021/07/05