| Message ID | 20190902080603.5636-4-horms+renesas@verge.net.au (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | ravb: Remove use of undocumented registers | expand |
Hi Simon-san, > From: Simon Horman, Sent: Monday, September 2, 2019 5:06 PM > > Only use the TROCR register on R-Car Gen3. > It is not present on other SoCs. > > Offsets used for the undocumented registers are also considered reserved > and should not be written to. > > After some internal investigation with Renesas it remains unclear why this > driver accesses these fields on R-Car Gen2 but regardless of what the > historical reasons are the current code is considered incorrect. > > Signed-off-by: Simon Horman <horms+renesas@verge.net.au> Thank you for the patch! Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Best regards, Yoshihiro Shimoda
On 09/02/2019 11:06 AM, Simon Horman wrote: > Only use the TROCR register on R-Car Gen3. > It is not present on other SoCs. > > Offsets used for the undocumented registers are also considered reserved > and should not be written to. > > After some internal investigation with Renesas it remains unclear why this > driver accesses these fields on R-Car Gen2 but regardless of what the > historical reasons are the current code is considered incorrect. Most probably copy&paste from sh_eth.c... > Signed-off-by: Simon Horman <horms+renesas@verge.net.au> [...] Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> MBR, Sergei
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h index bdb051f04b0c..a9c89d5d8898 100644 --- a/drivers/net/ethernet/renesas/ravb.h +++ b/drivers/net/ethernet/renesas/ravb.h @@ -193,7 +193,7 @@ enum ravb_reg { GECMR = 0x05b0, MAHR = 0x05c0, MALR = 0x05c8, - TROCR = 0x0700, /* Undocumented? */ + TROCR = 0x0700, /* R-Car Gen3 only */ CEFCR = 0x0740, FRECR = 0x0748, TSFRCR = 0x0750, diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index b538cc6fdbb7..de9aa8c47f1c 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -1621,8 +1621,10 @@ static struct net_device_stats *ravb_get_stats(struct net_device *ndev) stats0 = &priv->stats[RAVB_BE]; stats1 = &priv->stats[RAVB_NC]; - nstats->tx_dropped += ravb_read(ndev, TROCR); - ravb_write(ndev, 0, TROCR); /* (write clear) */ + if (priv->chip_id == RCAR_GEN3) { + nstats->tx_dropped += ravb_read(ndev, TROCR); + ravb_write(ndev, 0, TROCR); /* (write clear) */ + } nstats->rx_packets = stats0->rx_packets + stats1->rx_packets; nstats->tx_packets = stats0->tx_packets + stats1->tx_packets;
Only use the TROCR register on R-Car Gen3. It is not present on other SoCs. Offsets used for the undocumented registers are also considered reserved and should not be written to. After some internal investigation with Renesas it remains unclear why this driver accesses these fields on R-Car Gen2 but regardless of what the historical reasons are the current code is considered incorrect. Signed-off-by: Simon Horman <horms+renesas@verge.net.au> --- drivers/net/ethernet/renesas/ravb.h | 2 +- drivers/net/ethernet/renesas/ravb_main.c | 6 ++++-- 2 files changed, 5 insertions(+), 3 deletions(-)