On Tue, Dec 22, 2009 at 12:06 AM, Roman Fietze
<roman.fie...@telemotive.de> wrote:
>
Need patch description
> Signed-off-by: Roman Fietze <roman.fie...@telemotive.de>
> ---
> arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c | 40
> ++++++++++++++++---------
> 1 files changed, 26 insertions(+), 14 deletions(-)
>
> diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
> b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
> index a7cd585..48f2b4f 100644
> --- a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
> +++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
> @@ -84,8 +84,7 @@ static void mpc52xx_lpbfifo_kick(struct
> mpc52xx_lpbfifo_request *req)
> struct bcom_bd *bd;
> void __iomem *reg;
> u32 *data;
> - int i;
> - int bit_fields;
> + u32 bit_fields;
> int rflags = req->flags;
>
> /* Set and clear the reset bits; is good practice in User Manual */
> @@ -96,27 +95,32 @@ static void mpc52xx_lpbfifo_kick(struct
> mpc52xx_lpbfifo_request *req)
>
> /* Set CS and BPT */
> bit_fields = MPC52xx_SCLPC_CONTROL_CS(req->cs) | 0x8;
> - if (!(mpc52xx_lpbfifo_is_write(rflags))) {
> + if (!(mpc52xx_lpbfifo_is_write(rflags)))
> bit_fields |= MPC52xx_SCLPC_CONTROL_RWB_RECEIVE; /*
> read mode */
> - bit_fields |= MPC52xx_SCLPC_CONTROL_FLUSH;
> - }
> - out_be32(&lpbfifo.regs->control, bit_fields);
Writing the control register is being deferred to later. I'm not
convinced this is correct (see comment on previous patch).
>
> if (!mpc52xx_lpbfifo_is_dma(rflags)) {
> - /* While the FIFO can be setup for transfer sizes as large as
> - * 16M-1, the FIFO itself is only 512 bytes deep and it does
> - * not generate interrupts for FIFO full events (only transfer
> - * complete will raise an IRQ). Therefore when not using
> - * Bestcomm to drive the FIFO it needs to either be polled, or
> - * transfers need to constrained to the size of the fifo.
> + /* While the FIFO can be setup for transfer sizes as
> + * large as 16M-1, the FIFO itself is only 512 bytes
> + * deep and it does not generate interrupts for FIFO
> + * full events (only transfer complete will raise an
> + * IRQ). Therefore when not using Bestcomm to drive the
> + * FIFO it needs to either be polled, or transfers need
> + * to constrained to the size of the fifo.
Drop formatting changes or spilt to separate patch.
> *
> * This driver restricts the size of the transfer
> + *
> + * The last block of data will be received with the
> + * flush bit set. This avoids stale read data.
> */
> if (transfer_size > 512)
> transfer_size = 512;
> + else if (!(mpc52xx_lpbfifo_is_write(rflags)))
> + bit_fields |= MPC52xx_SCLPC_CONTROL_FLUSH;
>
> /* Load the FIFO with data */
> if (mpc52xx_lpbfifo_is_write(rflags)) {
> + size_t i;
> +
> reg = &lpbfifo.regs->fifo_data;
> data = req->data + req->pos;
> for (i = 0; i < transfer_size; i += 4)
> @@ -128,6 +132,12 @@ static void mpc52xx_lpbfifo_kick(struct
> mpc52xx_lpbfifo_request *req)
> MPC52xx_SCLPC_ENABLE_NIE |
> MPC52xx_SCLPC_ENABLE_ME));
> } else {
> +
> + /* In DMA mode we can always set the flush bit to avoid
> + * stale read data. */
> + if (!(mpc52xx_lpbfifo_is_write(rflags)))
> + bit_fields |= MPC52xx_SCLPC_CONTROL_FLUSH;
> +
> /* Choose the correct direction
> *
> * Configure the watermarks so DMA will always complete
> correctly.
> @@ -168,6 +178,8 @@ static void mpc52xx_lpbfifo_kick(struct
> mpc52xx_lpbfifo_request *req)
> bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL);
> }
>
> + out_be32(&lpbfifo.regs->control, bit_fields);
> +
> /* Set packet size and kick it off */
> out_be32(&lpbfifo.regs->packet_size.packet_size,
> MPC52xx_SCLPC_PACKET_SIZE_RESTART | transfer_size);
> if (mpc52xx_lpbfifo_is_dma(rflags))
> @@ -455,7 +467,7 @@ mpc52xx_lpbfifo_probe(struct of_device *op, const struct
> of_device_id *match)
> goto err_irq;
>
> /* Request the Bestcomm receive (fifo --> memory) task and IRQ */
> - lpbfifo.bcom_rx_task = bcom_gen_bd_rx_init(4,
> + lpbfifo.bcom_rx_task = bcom_gen_bd_rx_init(2,
unrelated change (and this line was also changed in an earlier patch)
> res.start + offsetof(struct
> mpc52xx_sclpc, fifo_data),
> BCOM_INITIATOR_SCLPC,
> BCOM_IPR_SCLPC,
> 16 * 1024 * 1024);
> @@ -469,7 +481,7 @@ mpc52xx_lpbfifo_probe(struct of_device *op, const struct
> of_device_id *match)
> goto err_bcom_rx_irq;
>
> /* Request the Bestcomm transmit (memory --> fifo) task and IRQ */
> - lpbfifo.bcom_tx_task = bcom_gen_bd_tx_init(4,
> + lpbfifo.bcom_tx_task = bcom_gen_bd_tx_init(2,
ditto
> res.start + offsetof(struct
> mpc52xx_sclpc, fifo_data),
> BCOM_INITIATOR_SCLPC,
> BCOM_IPR_SCLPC);
> --
> 1.6.5.5
>
>
>
> --
> Roman Fietze Telemotive AG Büro Mühlhausen
> Breitwiesen 73347 Mühlhausen
> Tel.: +49(0)7335/18493-45 http://www.telemotive.de
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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