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Date: Fri, 14 May 2010 16:41:59 +0200
From: Sebastien Jan <s-jan@...com>
To: Carlos Chinea <carlos.chinea@...ia.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: Re: [RFC PATCHv2 2/7] OMAP SSI: Introducing OMAP SSI driver
Hi Carlos,
Please see my comments inlined.
On Friday 07 May 2010 17:18:32 Carlos Chinea wrote:
[strip]
> diff --git a/drivers/hsi/controllers/omap_ssi.c
[strip]
> +
> +/**
> + * struct omap_ssm_ctx - OMAP synchronous serial module (TX/RX) context
> + * @mode: Bit transmission mode
> + * @channels: Number of channels
> + * @framesize: Frame size in bits
> + * @timeout: RX frame timeout
> + * @divisot: TX divider
Typo: s/divisot/divisor
> + * @arb_mode: Arbitration mode for TX frame (Round robin, priority)
> + */
> +struct omap_ssm_ctx {
> + u32 mode;
> + u32 channels;
> + u32 frame_size;
> + union {
> + u32 timeout; /* Rx Only */
> + struct {
> + u32 arb_mode;
> + u32 divisor;
> + }; /* Tx only */
> + };
> +};
> +
> +/**
> + * struct omap_ssi_port - OMAP SSI port data
> + * @dev: device associated to the port (HSI port)
> + * @sst_dma: SSI transmitter physical base address
> + * @ssr_dma: SSI receiver physical base address
> + * @sst_base: SSI transmitter base address
> + * @ssr_base: SSI receiver base address
wk_lock description is missing here
> + * @lock: Spin lock to serialize access to the SSI port
> + * @channels: Current number of channels configured (1,2,4 or 8)
> + * @txqueue: TX message queues
> + * @rxqueue: RX message queues
> + * @brkqueue: Queue of incoming HWBREAK requests (FRAME mode)
> + * @irq: IRQ number
> + * @wake_irq: IRQ number for incoming wake line (-1 if none)
> + * @pio_tasklet: Bottom half for PIO transfers and events
> + * @wake_tasklet: Bottom half for incoming wake events
> + * @wkin_cken: Keep track of clock references due to the incoming wake
> line
> + * @wake_refcount: Reference count for output wake line
s/wake_refcount/wk_refcount
> + * @sys_mpu_enable: Context for the interrupt enable register for irq 0
> + * @sst: Context for the synchronous serial transmitter
> + * @ssr: Context for the synchronous serial receiver
> + */
> +struct omap_ssi_port {
> + struct device *dev;
> + dma_addr_t sst_dma;
> + dma_addr_t ssr_dma;
> + unsigned long sst_base;
> + unsigned long ssr_base;
> + spinlock_t wk_lock;
> + spinlock_t lock;
> + unsigned int channels;
> + struct list_head txqueue[SSI_MAX_CHANNELS];
> + struct list_head rxqueue[SSI_MAX_CHANNELS];
> + struct list_head brkqueue;
> + unsigned int irq;
> + int wake_irq;
> + struct tasklet_struct pio_tasklet;
> + struct tasklet_struct wake_tasklet;
> + unsigned int wkin_cken:1; /* Workaround */
> + int wk_refcount;
> + /* OMAP SSI port context */
> + u32 sys_mpu_enable; /* We use only one irq */
> + struct omap_ssm_ctx sst;
> + struct omap_ssm_ctx ssr;
> +};
> +
[strip]
> +
> +static void ssi_pio_complete(struct hsi_port *port, struct list_head
> *queue) +{
> + struct hsi_controller *ssi =
> to_hsi_controller(port->device.parent); + struct omap_ssi_controller
> *omap_ssi = hsi_controller_drvdata(ssi); + struct omap_ssi_port
> *omap_port = hsi_port_drvdata(port);
> + struct hsi_msg *msg;
> + u32 *buf;
> + u32 val;
> +
> + spin_lock(&omap_port->lock);
> + msg = list_first_entry(queue, struct hsi_msg, link);
> + if ((!msg->sgt.nents) || (!msg->sgt.sgl->length)) {
> + msg->actual_len = 0;
> + msg->status = HSI_STATUS_PENDING;
> + }
> + if (msg->status == HSI_STATUS_PROCEDING) {
> + buf = sg_virt(msg->sgt.sgl) + msg->actual_len;
> + if (msg->ttype == HSI_MSG_WRITE)
> + __raw_writel(*buf, omap_port->sst_base +
> +
> SSI_SST_BUFFER_CH_REG(msg->channel)); + else
> + *buf = __raw_readl(omap_port->ssr_base +
> +
> SSI_SSR_BUFFER_CH_REG(msg->channel)); +
> dev_dbg(&port->device, "ch %d ttype %d 0x%08x\n", msg->channel, +
> msg->ttype, *buf); +
> msg->actual_len += sizeof(*buf);
> + if (msg->actual_len >= msg->sgt.sgl->length)
> + msg->status = HSI_STATUS_COMPLETED;
> + /*
> + * Wait for the last written frame to be really sent before
> + * we call the complete callback
> + */
> + if ((msg->status == HSI_STATUS_PROCEDING) ||
> + ((msg->status == HSI_STATUS_COMPLETED) &&
> + (msg->ttype == HSI_MSG_WRITE)))
> + goto out;
> +
> + }
> + if (msg->status == HSI_STATUS_PROCEDING)
> + goto out;
> + /* Transfer completed at this point */
> + val = __raw_readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num,
> 0)); + if (msg->ttype == HSI_MSG_WRITE) {
> + val &= ~SSI_DATAACCEPT(msg->channel);
> + ssi_clk_disable(ssi); /* Release clocks for write transfer
> */ + } else {
> + val &= ~SSI_DATAAVAILABLE(msg->channel);
> + }
> + __raw_writel(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num,
> 0)); + list_del(&msg->link);
> + spin_unlock(&omap_port->lock);
> + msg->complete(msg);
> + spin_lock(&omap_port->lock);
> + ssi_start_transfer(queue);
> +out:
> + spin_unlock(&omap_port->lock);
> +}
> +
> +static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
> +{
> + struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
> + struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
> + struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
> + unsigned int dir;
> + u32 csr;
> + u32 val;
> +
> + spin_lock(&omap_ssi->lock);
> +
> + val = __raw_readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
> + val &= ~SSI_GDD_LCH(lch);
> + __raw_writel(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
> +
> + if (msg->ttype == HSI_MSG_READ) {
> + dir = DMA_FROM_DEVICE;
> + val = SSI_DATAAVAILABLE(msg->channel);
> + ssi_clk_disable(ssi);
> + } else {
> + dir = DMA_TO_DEVICE;
> + val = SSI_DATAACCEPT(msg->channel);
> + /* Keep clocks reference for write pio event */
> + }
> + dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
> + csr = __raw_readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
> + omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
> + if (csr & SSI_CSR_TOUR) { /* Timeout error */
> + msg->status = HSI_STATUS_ERROR;
> + msg->actual_len = 0;
> + list_del(&msg->link); /* Dequeue msg */
> + spin_unlock(&omap_ssi->lock);
> + msg->complete(msg);
> + return;
> + }
> +
> + val |= __raw_readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num,
> 0)); + __raw_writel(val, omap_ssi->sys +
> SSI_MPU_ENABLE_REG(port->num, 0)); +
> + msg->status = HSI_STATUS_COMPLETED;
> + msg->actual_len = sg_dma_len(msg->sgt.sgl);
> + spin_unlock(&omap_ssi->lock);
> +}
Don't you need to check the queue related to this transfer at this point, to
start the potentially next queued transfer on the same channel? (calling
ssi_start_transfer(), like in ssi_pio_complete()?)
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