Re: [PATCH 1/3] i3c: master: Add driver for Synopsys DesignWare IP

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Hi Boris,


On 27-07-2018 14:38, Boris Brezillon wrote:
Hi Victor,

On Fri, 20 Jul 2018 21:57:50 +0100
Vitor soares <Vitor.Soares@xxxxxxxxxxxx> wrote:

This patch add driver for Synopsys DesignWare IP on top of
I3C subsystem patchset proposal V6
The fact that you based your work on v6 of the I3C patchset should be
placed ....

Signed-off-by: Vitor soares <soares@xxxxxxxxxxxx>
---
... here, so that it does not appear in the final commit message.


[...]

I will do that in the next submission.

+static int dw_i3c_master_get_free_pos(struct dw_i3c_master *master)
+{
+	if (!(master->free_pos & GENMASK(master->maxdevs - 1, 0)))
+		return -ENOSPC;
+
+	return ffs(master->free_pos) - 1;
+}
Okay, maybe we can have a generic infrastructure for that part (I have
the same logic in the Cadence driver), but let's keep that for later.

I think everyone will need a table (SW or HW) to mask the slots available for DAA.


+
+static void dw_i3c_master_wr_tx_fifo(struct dw_i3c_master *master,
+				     const u8 *bytes, int nbytes)
+{
+	int i, j;
+
+	for (i = 0; i < nbytes; i += 4) {
+		u32 data = 0;
+
+		for (j = 0; j < 4 && (i + j) < nbytes; j++)
+			data |= (u32)bytes[i + j] << (j * 8);
+
+		writel(data, master->regs + RX_TX_DATA_PORT);
Maybe you can use writesl() as suggested by Arnd in his review of the
Cadence driver.

Andy also suggest get_unaligned_le32() / put_unaligned_le32() to read/write from FIFOS. I will try both solutions.


+	}
+}
+
[...]

+
+static void dw_i3c_master_detach_i2c_dev(struct i2c_dev_desc *dev)
+{
+	struct dw_i3c_i2c_dev_data *data = i2c_dev_get_master_data(dev);
+	struct i3c_master_controller *m = i2c_dev_get_master(dev);
+	struct dw_i3c_master *master = to_dw_i3c_master(m);
+
+	writel(NULL,
		^ 0 not NULL

I will change it.


+	       master->regs +
+	       DEV_ADDR_TABLE_LOC(master->datstartaddr, data->index));
+
+	i2c_dev_set_master_data(dev, NULL);
+	master->addrs[data->index] = 0;
+	master->free_pos |= BIT(data->index);
+	kfree(data);
+}
+
+static int dw_i3c_probe(struct platform_device *pdev)
+{
+	struct dw_i3c_master *master;
+	struct resource *res;
+	int ret, irq;
+
+	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->core_clk = devm_clk_get(&pdev->dev, "core_clk");
+	if (IS_ERR(master->core_clk))
+		return PTR_ERR(master->core_clk);
+
+	master->core_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
+								    "core_rst");
+	if (IS_ERR(master->core_rst))
+		return PTR_ERR(master->core_rst);
+
+	ret = clk_prepare_enable(master->core_clk);
+	if (ret)
+		goto err_disable_core_clk;
+
+	reset_control_deassert(master->core_rst);
+
+	spin_lock_init(&master->xferqueue.lock);
+	INIT_LIST_HEAD(&master->xferqueue.list);
+
+	writel(INTR_ALL, master->regs + INTR_STATUS);
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(&pdev->dev, irq,
+			       dw_i3c_master_irq_handler, 0,
+			       dev_name(&pdev->dev), master);
+	if (ret)
+		goto err_assert_rst;
+
+	platform_set_drvdata(pdev, master);
+
+	ret = readl(master->regs + QUEUE_STATUS_LEVEL);
+	master->caps.cmdfifodepth = QUEUE_STATUS_LEVEL_CMD(ret);
+
+	ret = readl(master->regs + DATA_BUFFER_STATUS_LEVEL);
+	master->caps.datafifodepth = DATA_BUFFER_STATUS_LEVEL_TX(ret);
+
+	ret = readl(master->regs + DEVICE_ADDR_TABLE_POINTER);
+	master->datstartaddr = ret;
+	master->maxdevs = ret >> 16;
+	master->free_pos = GENMASK(master->maxdevs - 1, 0);
+
+	/* read controller version */
+	ret = readl(master->regs + I3C_VER_ID);
+	master->version[0] = (char)(ret >> 24);
+	master->version[1] = '.';
+	master->version[2] = (char)(ret >> 16);
+	master->version[3] = (char)(ret >> 8);
+	master->version[4] = '\0';
+
+	/* read controller type */
+	ret = readl(master->regs + I3C_VER_TYPE);
+	master->type[0] = (char)(ret >> 24);
+	master->type[1] = (char)(ret >> 16);
+	master->type[2] = (char)(ret >> 8);
+	master->type[3] = (char) ret;
+	master->type[4] = '\0';
Hm, do you really intend to read these as strings? If you do, maybe you
can use sprintf() here:

	sprintf(master->version, "%c.%c%c", ...)
	sprintf(master->type, "%c%c%c%c", ...)

Maybe this information is unnecessary. I will remove it.



+
+	ret = i3c_master_register(&master->base, &pdev->dev,
+				  &dw_mipi_i3c_ops, false);
+	if (ret)
+		goto err_assert_rst;
+
+	dev_info(&pdev->dev, "Synopsys DW MIPI I3C Master: version %s-%s\n",
+		 master->version, master->type);
+
+	return 0;
+
+err_assert_rst:
+	reset_control_assert(master->core_rst);
+
+err_disable_core_clk:
+	clk_disable_unprepare(master->core_clk);
+
+	return ret;
+}
The driver looks pretty good already, and I'm pleasantly surprised to
see that the Synopsys IP works pretty much the same way the Cadence one
does. I could find some of the logic I implemented in the Cadence
driver almost directly applied to this one, so I think there's room for
code factorization. Anyway, let's see what the next controller looks
like before doing that.

Thanks for sharing your work early and for reviewing the previous
versions of the I3C patchset.

Regards,

Boris

I tried to not reinvent the wheel. Right now the test with I3C devices are running very well.
I still have one or another detail that can be optimize.

Thanks for your feedback.

Best regards,
Vitor Soares


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