[v5 3/3] sata: imx: add ahci sata support on imx platforms

Zhu Richard-R65037 r65037 at freescale.com
Fri Jul 12 03:42:13 EDT 2013


Hi Shawn:
Thanks for your comments.

Best Regards
Richard Zhu


-----Original Message-----
From: Shawn Guo [mailto:shawn.guo at linaro.org] 
Sent: Friday, July 12, 2013 3:02 PM
To: Richard Zhu
Cc: linux-arm-kernel at lists.infradead.org; jgarzik at pobox.com; tj at kernel.org; rob.herring at calxeda.com; s.hauer at pengutronix.de; linux-ide at vger.kernel.org; Zhu Richard-R65037
Subject: Re: [v5 3/3] sata: imx: add ahci sata support on imx platforms

On Thu, Jul 11, 2013 at 05:10:31PM +0800, Richard Zhu wrote:
> From: Richard Zhu <r65037 at freescale.com>
> 
> imx6q contains one Synopsys AHCI SATA controller, But it can't shares 
> ahci_platform driver with other controllers.
> Because there are some misalignments of the generic AHCI controller.
> The bits definitions of the HBA registers, the Vendor Specific 
> registers, the AHCI PHY clock and the AHCI signals adjustment 
> window(GPR13 Reg).
>  - CAP_SSS(bit20) of the HOST_CAP is writable, default  value is '0', 
> should be configured to be '1'
>  - bit0 (only one AHCI SATA port on imx6q) of the  HOST_PORTS_IMPL 
> should be set to be '1'.(default 0)
>  - One Vendor Specific register HOST_TIMER1MS(offset:0xe0)  should be 
> configured regarding to the frequency of AHB  bus clock.
>  - Configurations of the AHCI PHY clock, and the signal  parameters of 
> the GPR13
> 
> Setup its own ahci sata driver, contained the imx6q specific 
> initialized codes, re-use the generic ahci_platform drier, and

s/drier/driver
[Richard] One typo error, would be changed.

> keep the generic ahci_platform driver clean as much as possible.
> 
> Signed-off-by: Richard Zhu <r65037 at freescale.com>
> ---
>  drivers/ata/Kconfig    |    9 ++
>  drivers/ata/Makefile   |    1 +
>  drivers/ata/sata_imx.c |  233 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 243 insertions(+), 0 deletions(-)  create mode 
> 100644 drivers/ata/sata_imx.c
> 
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig index 
> a5a3ebc..275dc2c 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -97,6 +97,15 @@ config SATA_AHCI_PLATFORM
>  
>  	  If unsure, say N.
>  
> +config SATA_IMX
> +	tristate "Freescale i.MX AHCI SATA support"
> +	depends on SATA_AHCI_PLATFORM
> +	help
> +	  This option enables support for the Freescale i.MX SoC's
> +	  onboard AHCI SATA.
> +
> +	  If unsure, say N.
> +
>  config SATA_FSL
>  	tristate "Freescale 3.0Gbps SATA support"
>  	depends on FSL_SOC
> diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile index 
> c04d0fd..04b1c6c 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_SATA_INIC162X)	+= sata_inic162x.o
>  obj-$(CONFIG_SATA_SIL24)	+= sata_sil24.o
>  obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
>  obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
> +obj-$(CONFIG_SATA_IMX)		+= sata_imx.o
>  
>  # SFF w/ custom DMA
>  obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
> diff --git a/drivers/ata/sata_imx.c b/drivers/ata/sata_imx.c new file 
> mode 100644 index 0000000..de6330e
> --- /dev/null
> +++ b/drivers/ata/sata_imx.c
> @@ -0,0 +1,233 @@
> +/*
> + * Freescale IMX AHCI SATA platform driver
> + * Copyright 2013 Freescale Semiconductor, Inc.
> + *
> + * based on the AHCI SATA platform driver by Jeff Garzik and Anton 
> +Vorontsov
> + *
> + * This program is free software; you can redistribute it and/or 
> +modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but 
> +WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
> +or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 
> +License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License 
> +along with
> + * this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/ahci_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> +#include "ahci.h"
> +
> +enum {
> +	HOST_TIMER1MS = 0xe0, /* Timer 1-ms */ };
> +
> +struct imx_ahci_priv {
> +	struct platform_device *imx_ahci_pdev;
> +	struct clk *sata_ref_clk;
> +	struct regmap *gpr;
> +};
> +
> +/* imx6q ahci module initialization. */ static int 
> +imx6q_sata_init(struct device *dev, void __iomem *mmio) {
> +	int ret = 0;
> +	unsigned int rc;

The variable name is confusing. "rc" generally means return code.
[Richard] Accepted. Would be changed.
> +	struct clk *ahb_clk;
> +	struct device *p_dev = dev->parent;
> +	struct imx_ahci_priv *imxpriv =  dev_get_drvdata(p_dev);

I would go dev_get_drvdata(dev->parent), since dev->parent is even more readable than p_dev.
[Richard] Accepted.

> +
> +	imxpriv->gpr =
> +		syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
> +	if (IS_ERR(imxpriv->gpr)) {
> +		dev_err(dev, "failed to find fsl,imx6q-iomux-gpr regmap\n");
> +		return PTR_ERR(imxpriv->gpr);
> +	}

Move it into imx_ahci_probe().
[Richard] The codes "> +		syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr"); " is imx6q specific.
I think it's better to place these codes in the imx6q_sata_init(). Otherwise, the probe maybe broken here, when imx53
sata use sata_imx driver in future.

> +
> +	imxpriv->sata_ref_clk = devm_clk_get(dev, "sata_ref");
> +	if (IS_ERR(imxpriv->sata_ref_clk)) {
> +		dev_err(dev, "can't get sata_ref clock.\n");
> +		return PTR_ERR(imxpriv->sata_ref_clk);
> +	}

Ditto
[Richard] Accepted.

> +
> +	ret = clk_prepare_enable(imxpriv->sata_ref_clk);
> +	if (ret < 0) {
> +		dev_err(dev, "prepare-enable sata_ref clock err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * set PHY Paremeters, two steps to configure the GPR13,
> +	 * one write for rest of parameters, mask of first write
> +	 * is 0x07fffffd, and the other one write for setting
> +	 * the mpll_clk_en.
> +	 */
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_RX_EQ_VAL_MASK
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_MASK
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_MASK
> +			| IMX6Q_GPR13_SATA_SPD_MODE_MASK
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_MASK
> +			| IMX6Q_GPR13_SATA_TX_BOOST_MASK
> +			| IMX6Q_GPR13_SATA_TX_LVL_MASK
> +			| IMX6Q_GPR13_SATA_TX_EDGE_RATE
> +			, IMX6Q_GPR13_SATA_RX_EQ_VAL_3_0_DB
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_SATA2M
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F
> +			| IMX6Q_GPR13_SATA_SPD_MODE_3P0G
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_9_16
> +			| IMX6Q_GPR13_SATA_TX_BOOST_3_33_DB
> +			| IMX6Q_GPR13_SATA_TX_LVL_1_025_V);
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	usleep_range(100, 200);
> +
> +	/*
> +	 * Configure the HWINIT bits of the HOST_CAP and HOST_PORTS_IMPL,
> +	 * and IP vendor specific register HOST_TIMER1MS.
> +	 *
> +	 * Configure CAP_SSS (support stagered spin up).
> +	 * Implement the port0.
> +	 * Get the ahb clock rate, and configure the TIMER1MS register.
> +	 */
> +	rc = readl(mmio + HOST_CAP);
> +	if (!(rc & HOST_CAP_SSS)) {
> +		rc |= HOST_CAP_SSS;
> +		writel(rc, mmio + HOST_CAP);
> +	}
> +	rc = readl(mmio + HOST_PORTS_IMPL);
> +	if (!(rc & 0x1)) {
> +		rc |= 0x1;
> +		writel(rc, mmio + HOST_PORTS_IMPL);
> +	}
> +
> +	ahb_clk = devm_clk_get(dev, "ahb");

If you need to get ahb clock, please specify it in your DTS node.  Right now, you only have the following two clocks in the DTS.

	clocks = <&clks 154>, <&clks 187>;
	clock-names = "sata", "sata_ref";

You code happens to work because of the following call in clk-imx6q.c.

	clk_register_clkdev(clk[ahb], "ahb", NULL);

But you shouldn't reply on that.  With all users moved to looking up clocks from device tree, we would remove it from clock driver.

Also, please have a clk pointer in imx_ahci_priv and call devm_clk_get() in imx_ahci_probe().
[Richard] Accepted. Would add "ahb" to sata related dts changes.

> +	if (IS_ERR(ahb_clk)) {
> +		dev_err(dev, "no ahb clock.\n");
> +		clk_disable_unprepare(imxpriv->sata_ref_clk);
> +		devm_clk_put(dev, imxpriv->sata_ref_clk);
> +		return PTR_ERR(ahb_clk);
> +	}
> +	rc = clk_get_rate(ahb_clk) / 1000;
> +	writel(rc, mmio + HOST_TIMER1MS);
> +	devm_clk_put(dev, ahb_clk);
> +
> +	return 0;
> +}
> +
> +static void imx6q_sata_exit(struct device *dev) {
> +	struct device *p_dev = dev->parent;
> +	struct imx_ahci_priv *imxpriv =  dev_get_drvdata(p_dev);

dev_get_drvdata(dev->parent);
[Richard] Accepted.

> +
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			!IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	clk_disable_unprepare(imxpriv->sata_ref_clk);
> +}
> +
> +static struct ahci_platform_data imx6q_sata_pdata = {
> +	.init = imx6q_sata_init,
> +	.exit = imx6q_sata_exit,
> +};

Put a blank line here.

> +static const struct of_device_id imx_ahci_of_match[] = {
> +	{ .compatible = "fsl,imx6q-ahci", .data = &imx6q_sata_pdata},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, imx_ahci_of_match);
> +
> +static void imx_ahci_platform_release(struct device *dev) {
> +	return;
> +}

Is this empty function mandatory?
[Richard] Introduce in the previous patch-set, It can be removed in the current version.

> +
> +static int imx_ahci_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct resource *mem, *irq, res[2];
> +	const struct of_device_id *of_id;
> +	const struct ahci_platform_data *pdata = NULL;
> +	struct imx_ahci_priv *imxpriv;
> +	int ret;
> +
I would drop this blank line and move the following two line above "int ret;".
[Richard] Accepted. 

> +	struct device *imx_dev;
> +	struct platform_device *imx_ahci_pdev;

These two variable names are confusing.  I would name them ahci_dev and ahci_pdev, as they are all about generic "ahci" rather than imx specific one.
[Richard] Accepted.

> +
> +	imx_ahci_pdev = platform_device_alloc("ahci", -1);
> +	if (!imx_ahci_pdev)
> +		return -ENODEV;
> +
> +	imx_dev = &imx_ahci_pdev->dev;
> +	imx_dev->release = imx_ahci_platform_release;
> +	imx_dev->parent = dev;
> +
> +	imxpriv = devm_kzalloc(dev, sizeof(*imxpriv), GFP_KERNEL);
> +	if (!imxpriv) {
> +		dev_err(dev, "can't alloc ahci_host_priv\n");
> +		return -ENOMEM;
> +	}
> +
> +	imxpriv->imx_ahci_pdev = imx_ahci_pdev;

So imx_ahci_pdev in imx_ahci_priv is also confusing.
[Richard] imx_ahci_pdev would be replaced by ahci_pdev.

> +	platform_set_drvdata(pdev, imxpriv);
> +
> +	of_id = of_match_device(imx_ahci_of_match, dev);
> +	if (of_id)
> +		pdata = of_id->data;
> +	else
> +		return -EINVAL;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> +	if (!mem || !irq) {
> +		dev_err(dev, "no mmio/irq resource\n");
> +		return -EINVAL;
> +	}
> +
> +	res[0] = *mem;
> +	res[1] = *irq;
> +
> +	imx_dev->coherent_dma_mask = DMA_BIT_MASK(32);
> +	imx_dev->dma_mask = &imx_dev->coherent_dma_mask;
> +	imx_dev->of_node = dev->of_node;
> +
> +	platform_device_add_resources(imx_ahci_pdev, res, 2);
> +	platform_device_add_data(imx_ahci_pdev, pdata, sizeof(*pdata));
> +
> +	ret = platform_device_add(imx_ahci_pdev);
> +
> +	return ret;

Can just be return platform_device_add(imx_ahci_pdev);
[Richard] Accepted.

Shawn

> +}
> +
> +static int imx_ahci_remove(struct platform_device *pdev) {
> +	struct imx_ahci_priv *imxpriv = platform_get_drvdata(pdev);
> +	struct platform_device *imx_ahci_pdev = imxpriv->imx_ahci_pdev;
> +
> +	platform_device_unregister(imx_ahci_pdev);
> +	return 0;
> +}
> +
> +static struct platform_driver imx_ahci_driver = {
> +	.probe = imx_ahci_probe,
> +	.remove = imx_ahci_remove,
> +	.driver = {
> +		.name = "sata-imx",
> +		.owner = THIS_MODULE,
> +		.of_match_table = imx_ahci_of_match,
> +	},
> +};
> +module_platform_driver(imx_ahci_driver);
> +
> +MODULE_DESCRIPTION("Freescale i.MX AHCI SATA platform driver"); 
> +MODULE_AUTHOR("Richard Zhu <Hong-Xing.Zhu at freescale.com>"); 
> +MODULE_LICENSE("GPL"); MODULE_ALIAS("sata:imx");
> --
> 1.7.5.4
> 




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