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SubjectRe: [PATCH v4 07/10] i3c: master: Add driver for Cadence IP
Date
Hi Boris,

Few things regarding Cadence IP driver:

On 6/4/18, 9:31 AM, "Boris Brezillon" <boris.brezillon@bootlin.com> wrote:

+static void cdns_i3c_master_handle_ibi(struct cdns_i3c_master *master,
+ u32 ibir)
+{
+ struct cdns_i3c_i2c_dev_data *data;
+ bool data_consumed = false;
+ struct i3c_ibi_slot *slot;
+ u32 id = IBIR_SLVID(ibir);
+ struct i3c_device *dev;
+ int len, i, j;
+ u8 *buf;
+
+ /*
+ * FIXME: maybe we should report the FIFO OVF errors to the upper
+ * layer.
+ */
+ if (id >= master->ibi.num_slots || (ibir & IBIR_ERROR))
+ goto out;
+
+ dev = master->ibi.slots[id];
+ spin_lock(&master->ibi.lock);
+
+ data = i3c_device_get_master_data(dev);
+ slot = i3c_generic_ibi_get_free_slot(data->ibi_pool);
+ if (!slot)
+ goto out_unlock;
+
+ buf = slot->data;
+
+ len = IBIR_XFER_BYTES(ibir);
+ for (i = 0; i < IBIR_XFER_BYTES(ibir); i += 4) {
+ u32 tmp = readl(master->regs + IBI_DATA_FIFO);
+
+ for (j = 0; j < 4 && i + j < dev->ibi->max_payload_len; j++)
+ buf[i + j] = tmp >> (j * 8);
+
+ }
+ slot->len = min_t(unsigned int, IBIR_XFER_BYTES(ibir),
+ dev->ibi->max_payload_len);
+ i3c_master_queue_ibi(dev, slot);
+ data_consumed = true;
+
+out_unlock:
+ spin_unlock(&master->ibi.lock);
+
+out:
+ /* Consume data from the FIFO if it's not been done already. */
+ if (!data_consumed) {
+ for (i = 0; i < IBIR_XFER_BYTES(ibir); i += 4)
+ readl(master->regs + IBI_DATA_FIFO);
+ }
+}

len variable is unneeded.

+static int cdns_i3c_master_probe(struct platform_device *pdev)
+{
+ struct cdns_i3c_master *master;
+ struct resource *res;
+ int ret, irq;
+ u32 val;
+
+ master = devm_kzalloc(&pdev->dev, sizeof(*master), GFP_KERNEL);
+ if (!master)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ master->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(master->regs))
+ return PTR_ERR(master->regs);
+
+ master->pclk = devm_clk_get(&pdev->dev, "pclk");
+ if (IS_ERR(master->pclk))
+ return PTR_ERR(master->pclk);
+
+ master->sysclk = devm_clk_get(&pdev->dev, "sysclk");
+ if (IS_ERR(master->pclk))
+ return PTR_ERR(master->pclk);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = clk_prepare_enable(master->pclk);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(master->sysclk);
+ if (ret)
+ goto err_disable_pclk;
+
+ if (readl(master->regs + DEV_ID) != DEV_ID_I3C_MASTER) {
+ ret = -EINVAL;
+ goto err_disable_sysclk;
+ }
+
+ spin_lock_init(&master->xferqueue.lock);
+ INIT_LIST_HEAD(&master->xferqueue.list);
+
+ INIT_WORK(&master->hj_work, cdns_i3c_master_hj);
+ writel(0xffffffff, master->regs + MST_IDR);
+ writel(0xffffffff, master->regs + SLV_IDR);
+ ret = devm_request_irq(&pdev->dev, irq, cdns_i3c_master_interrupt, 0,
+ dev_name(&pdev->dev), master);
+ if (ret)
+ goto err_disable_sysclk;
+
+ platform_set_drvdata(pdev, master);
+
+ val = readl(master->regs + CONF_STATUS0);
+
+ /* Device ID0 is reserved to describe this master. */
+ master->maxdevs = CONF_STATUS0_DEVS_NUM(val);
+ master->free_rr_slots = GENMASK(master->maxdevs, 1);
+
+ val = readl(master->regs + CONF_STATUS1);
+ master->caps.cmdfifodepth = CONF_STATUS1_CMD_DEPTH(val);
+ master->caps.rxfifodepth = CONF_STATUS1_RX_DEPTH(val);
+ master->caps.txfifodepth = CONF_STATUS1_TX_DEPTH(val);
+ master->caps.ibirfifodepth = 16;

IBI fifo depth is hardcoded. You can read this value from CONF_STATUS0 register.

+ master->caps.cmdrfifodepth = 16;

CMDR fifo depth is hardcoded. You can read this value from CONF_STATUS0 register also.

+
+ spin_lock_init(&master->ibi.lock);
+ master->ibi.num_slots = CONF_STATUS1_IBI_HW_RES(val);
+ master->ibi.slots = devm_kzalloc(&pdev->dev,
+ sizeof(*master->ibi.slots) *
+ master->ibi.num_slots,
+ GFP_KERNEL);
+ if (!master->ibi.slots)
+ goto err_disable_sysclk;
+
+ writel(IBIR_THR(1), master->regs + CMD_IBI_THR_CTRL);
+ writel(MST_INT_IBIR_THR, master->regs + MST_IER);
+ writel(DEVS_CTRL_DEV_CLR_ALL, master->regs + DEVS_CTRL);
+
+ ret = i3c_master_register(&master->base, &pdev->dev,
+ &cdns_i3c_master_ops, false);
+ if (ret)
+ goto err_disable_sysclk;
+
+ return 0;
+
+err_disable_sysclk:
+ clk_disable_unprepare(master->sysclk);
+
+err_disable_pclk:
+ clk_disable_unprepare(master->pclk);
+
+ return ret;
+}

Regards,
Przemyslaw Gaj

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