Re: [PATCH] net: macb: Add big endian CPU support

Nicolas Ferre
2015-02-24T12:57:11Z

Le 24/02/2015 08:39, Arun Chandran a écrit :
> This patch converts all __raw_readl and __raw_writel function calls
> to their corresponding readl_relaxed and writel_relaxed variants.
>
> It also tells the driver to set ahb_endian_swp_mgmt_en bit in dma_cfg
> when the cpu is configured in big endian mode.
>
> Signed-off-by: Arun Chandran <achandran@mvista.com>
> ---
> This patch is tested on xilinx ZC702 evaluation board with
> CONFIG_CPU_BIG_ENDIAN=y and booting NFS rootfs
> Added on the fly IP endianness detection according to
> comments from Michal Simek.
> ---
> ---
> drivers/net/ethernet/cadence/macb.c | 33 +++++++++++++++++++++++++++------
> drivers/net/ethernet/cadence/macb.h | 15 ++++++++-------
> 2 files changed, 35 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index ad76b8e..1642911 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -449,7 +449,7 @@ static void macb_update_stats(struct macb *bp)
> WARN_ON((unsigned long)(end - p - 1) != (MACB_TPF - MACB_PFR) / 4);
>
> for(; p < end; p++, reg++)
> - *p += __raw_readl(reg);
> + *p += readl_relaxed(reg);
> }
>
> static int macb_halt_tx(struct macb *bp)
> @@ -1578,6 +1578,7 @@ static u32 macb_dbw(struct macb *bp)
> static void macb_configure_dma(struct macb *bp)
> {
> u32 dmacfg;
> + u32 tmp, ncr;
>
> if (macb_is_gem(bp)) {
> dmacfg = gem_readl(bp, DMACFG) & ~GEM_BF(RXBS, -1L);
> @@ -1585,7 +1586,25 @@ static void macb_configure_dma(struct macb *bp)
> if (bp->dma_burst_length)
> dmacfg = GEM_BFINS(FBLDO, bp->dma_burst_length, dmacfg);
> dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L);
> - dmacfg &= ~GEM_BIT(ENDIA);
> + dmacfg &= ~GEM_BIT(ENDIA_PKT);

I think this will fail... (see below)

> +
> + /* Here we use the loopback bit of net_ctrl register to detect
> + * endianness on IP. save it first. Program swaped mode for
> + * management descriptor accesses if writing to loop back bit
> + * and reading it back brings no change in bit value.
> + */
> + ncr = macb_readl(bp, NCR);
> + __raw_writel(MACB_BIT(LLB), bp->regs + MACB_NCR);
> + tmp = __raw_readl(bp->regs + MACB_NCR);
> +
> + if (tmp == MACB_BIT(LLB))
> + dmacfg &= ~GEM_BIT(ENDIA_DESC);

Ditto

> + else
> + dmacfg |= GEM_BIT(ENDIA_DESC);

Ditto

> +
> + /* Restore net_ctrl */
> + macb_writel(bp, NCR, ncr);
> +
> if (bp->dev->features & NETIF_F_HW_CSUM)
> dmacfg |= GEM_BIT(TXCOEN);
> else
> @@ -1832,14 +1851,14 @@ static void gem_update_stats(struct macb *bp)
>
> for (i = 0; i < GEM_STATS_LEN; ++i, ++p) {
> u32 offset = gem_statistics[i].offset;
> - u64 val = __raw_readl(bp->regs + offset);
> + u64 val = readl_relaxed(bp->regs + offset);
>
> bp->ethtool_stats[i] += val;
> *p += val;
>
> if (offset == GEM_OCTTXL || offset == GEM_OCTRXL) {
> /* Add GEM_OCTTXH, GEM_OCTRXH */
> - val = __raw_readl(bp->regs + offset + 4);
> + val = readl_relaxed(bp->regs + offset + 4);
> bp->ethtool_stats[i] += ((u64)val) << 32;
> *(++p) += val;
> }
> @@ -2191,12 +2210,14 @@ static void macb_probe_queues(void __iomem *mem,
> *num_queues = 1;
>
> /* is it macb or gem ? */
> - mid = __raw_readl(mem + MACB_MID);
> + mid = readl_relaxed(mem + MACB_MID);
> +
> if (MACB_BFEXT(IDNUM, mid) != 0x2)
> return;
>
> /* bit 0 is never set but queue 0 always exists */
> - *queue_mask = __raw_readl(mem + GEM_DCFG6) & 0xff;
> + *queue_mask = readl_relaxed(mem + GEM_DCFG6) & 0xff;
> +
> *queue_mask |= 0x1;
>
> for (hw_q = 1; hw_q < MACB_MAX_QUEUES; ++hw_q)
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 31dc080..57f0a1a 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -229,7 +229,8 @@
> /* Bitfields in DMACFG. */
> #define GEM_FBLDO_OFFSET 0 /* fixed burst length for DMA */
> #define GEM_FBLDO_SIZE 5
> -#define GEM_ENDIA_OFFSET 7 /* endian swap mode for packet data access */
> +#define GEM_ENDIA_DESC_OFFSET 6 /* endian swap mode for management descriptor access */
> +#define GEM_ENDIA_PKT_OFFSET 7 /* endian swap mode for packet data access */

here you would need to define as well:
#define GEM_ENDIA_DESC_SIZE 1
#define GEM_ENDIA_PKT_SIZE 1
Otherwise, I suspect that the GEM_BIT() macro won't work well.

> #define GEM_ENDIA_SIZE 1

And you can remove this one ^^^^.

> #define GEM_RXBMS_OFFSET 8 /* RX packet buffer memory size select */
> #define GEM_RXBMS_SIZE 2
> @@ -423,17 +424,17 @@
>
> /* Register access macros */
> #define macb_readl(port,reg) \
> - __raw_readl((port)->regs + MACB_##reg)
> + readl_relaxed((port)->regs + MACB_##reg)
> #define macb_writel(port,reg,value) \
> - __raw_writel((value), (port)->regs + MACB_##reg)
> + writel_relaxed((value), (port)->regs + MACB_##reg)
> #define gem_readl(port, reg) \
> - __raw_readl((port)->regs + GEM_##reg)
> + readl_relaxed((port)->regs + GEM_##reg)
> #define gem_writel(port, reg, value) \
> - __raw_writel((value), (port)->regs + GEM_##reg)
> + writel_relaxed((value), (port)->regs + GEM_##reg)
> #define queue_readl(queue, reg) \
> - __raw_readl((queue)->bp->regs + (queue)->reg)
> + readl_relaxed((queue)->bp->regs + (queue)->reg)
> #define queue_writel(queue, reg, value) \
> - __raw_writel((value), (queue)->bp->regs + (queue)->reg)
> + writel_relaxed((value), (queue)->bp->regs + (queue)->reg)
>
> /* Conditional GEM/MACB macros. These perform the operation to the correct
> * register dependent on whether the device is a GEM or a MACB. For registers
>

--
Nicolas Ferre