Re: [PATCH 1/6] ata: ahci: add AHCI support for Berlin SoCs

[Rob Herring <robherring2@gmail.com>]

On Tue, Apr 22, 2014 at 10:38 AM, Antoine Ténart
<antoine.tenart@free-electrons.com> wrote:
> Add support for the Berlin SoCs AHCI SATA controller allowing to
> interface with devices like external hard drives.
>
> Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com>
> ---
>  drivers/ata/Kconfig       |   9 +++
>  drivers/ata/Makefile      |   1 +
>  drivers/ata/ahci_berlin.c | 175 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 185 insertions(+)
>  create mode 100644 drivers/ata/ahci_berlin.c
>
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
> index 20e03a7eb8b4..c985dfcd5a6c 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -97,6 +97,15 @@ config SATA_AHCI_PLATFORM
>
>           If unsure, say N.
>
> +config AHCI_BERLIN
> +       tristate "Marvell Berlin AHCI SATA support"
> +       depends on ARCH_BERLIN
> +       help
> +         This option enables support for the Marvell Berlin SoC's
> +         onboard AHCI SATA.
> +
> +         If unsure, say N.
> +
>  config AHCI_DA850
>         tristate "DaVinci DA850 AHCI SATA support"
>         depends on ARCH_DAVINCI_DA850
> diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
> index 44c8016e565c..7fb78d1e0a44 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-$(CONFIG_AHCI_BERLIN)      += ahci_berlin.o libahci.o libahci_platform.o
>  obj-$(CONFIG_AHCI_DA850)       += ahci_da850.o libahci.o libahci_platform.o
>  obj-$(CONFIG_AHCI_IMX)         += ahci_imx.o libahci.o libahci_platform.o
>  obj-$(CONFIG_AHCI_SUNXI)       += ahci_sunxi.o libahci.o libahci_platform.o
> diff --git a/drivers/ata/ahci_berlin.c b/drivers/ata/ahci_berlin.c
> new file mode 100644
> index 000000000000..cf1c9d3b9d18
> --- /dev/null
> +++ b/drivers/ata/ahci_berlin.c
> @@ -0,0 +1,175 @@
> +/*
> + * Marvell Berlin AHCI SATA platform driver
> + *
> + * Copyright (C) 2014 Marvell Technology Group Ltd.
> + *
> + * Antoine Ténart <antoine.tenart@free-electrons.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/ahci_platform.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +
> +#include "ahci.h"
> +
> +#define PORT_VSR_ADDR          0x78
> +#define PORT_VSR_DATA          0x7C
> +#define HOST_VSA_ADDR          0xA0
> +#define HOST_VSA_DATA          0xA4
> +
> +static inline void ahci_berlin_reg_setbits(void __iomem *reg, u32 val)
> +{
> +       u32 regval;
> +
> +       regval = readl(reg);
> +       regval |= val;
> +       writel(regval, reg);
> +}
> +
> +static inline void ahci_berlin_reg_set(void __iomem *reg, u32 val)
> +{
> +       writel(val, reg);
> +}

Just use writel directly.

> +
> +static inline void ahci_berlin_reg_clear_set(void __iomem *reg, u32 clear_val,
> +                                            u32 set_val)
> +{
> +       u32 regval;
> +
> +       regval = readl(reg);
> +       regval &= ~(clear_val);
> +       regval |= set_val;
> +       writel(regval, reg);
> +}
> +
> +static void ahci_berlin_init(void __iomem *mmio)

I don't really see the point of a function to do 2 register writes of
magic values especially when the function name doesn't provide any
indication of what you are doing really.

> +{
> +       /* interface select */
> +       ahci_berlin_reg_set(mmio + HOST_VSA_ADDR, BIT(2));
> +       ahci_berlin_reg_set(mmio + HOST_VSA_ADDR,

2 writes to the same reg? Is this supposed to be the VSA_DATA register?

> +                           BIT(21) | BIT(18) | BIT(5) | BIT(4) | BIT(2));

Use of BIT is only helpful to people that don't understand hex. Can
you define what these bits are. Otherwise, just use 0x00240034 and
note that it is magic value which you have no idea what the bits are.

> +
> +}
> +
> +static void ahci_berlin_port_init(void __iomem *mmio, unsigned int ports)
> +{
> +       int p;
> +
> +       /* power down pll */
> +       ahci_berlin_reg_set(mmio + HOST_VSA_ADDR, 0x0);
> +       ahci_berlin_reg_setbits(mmio + HOST_VSA_DATA, BIT(6));
> +
> +       for (p = 0; p < ports; p++) {
> +               /* port control register */
> +               void __iomem *ctrl_reg = mmio + 0x100 + (p * 0x80);
> +
> +               /* set PHY mode to SATA, ref freq to 25 MHz */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR, 0x201);
> +               ahci_berlin_reg_clear_set(ctrl_reg + PORT_VSR_DATA,
> +                                         0xff, BIT(0));

So you have registers hidden behind an address and data register.
Perhaps a read and write function to provide that access rather than
all these set/clear bit functions.

> +
> +               /* set PHY up to 6 Gbps */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR, 0x225);
> +               ahci_berlin_reg_clear_set(ctrl_reg + PORT_VSR_DATA,
> +                                         BIT(11) | BIT(10), BIT(11));
> +
> +               /* set SEL_BITS to 40 bit */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR, 0x223);
> +               ahci_berlin_reg_clear_set(ctrl_reg + PORT_VSR_DATA,
> +                                         BIT(11) | BIT(10), BIT(11));
> +
> +               /* use max pll rate */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR, 0x202);
> +               ahci_berlin_reg_setbits(ctrl_reg + PORT_VSR_DATA, BIT(12));
> +
> +               /* CT timing fix */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR, BIT(6) | BIT(1));
> +               ahci_berlin_reg_set(ctrl_reg + PORT_VSR_ADDR,
> +                                   BIT(15) | BIT(13) | BIT(12) | BIT(11) |
> +                                   BIT(10) | BIT(2) | BIT(1));
> +
> +               /* set the controller speed */
> +               ahci_berlin_reg_set(ctrl_reg + PORT_SCR_CTL,
> +                                   BIT(6) | BIT(5) | BIT(0));
> +       }
> +
> +       /* power up pll */
> +       ahci_berlin_reg_set(mmio + HOST_VSA_ADDR, 0x0);
> +       ahci_berlin_reg_clear_set(mmio + HOST_VSA_DATA, BIT(6), 0x0);
> +}
> +
> +static const struct ata_port_info ahci_berlin_port_info = {
> +       .flags          = AHCI_FLAG_COMMON | ATA_FLAG_NCQ,
> +       .pio_mask       = ATA_PIO4,
> +       .udma_mask      = ATA_UDMA6,
> +       .port_ops       = &ahci_platform_ops,
> +};
> +
> +static int ahci_berlin_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct device_node *np = dev->of_node;
> +       struct ahci_host_priv *hpriv;
> +       int ret, nports, force_map = 0;
> +
> +       hpriv = ahci_platform_get_resources(pdev);
> +       if (IS_ERR(hpriv)) {
> +               dev_err(dev, "cannot get AHCI resources\n");
> +               return PTR_ERR(hpriv);
> +       }
> +
> +       ret = ahci_platform_enable_resources(hpriv);
> +       if (ret) {
> +               dev_err(dev, "cannot enable resources: %d\n", ret);
> +               return ret;
> +       }
> +
> +       nports = readl(hpriv->mmio + HOST_PORTS_IMPL);
> +
> +       /* force_map is modified only if the property is found */
> +       of_property_read_u32(np, "marvell,force-port-map", &force_map);
> +       if (force_map)
> +               nports = force_map;
> +
> +       ahci_berlin_init(hpriv->mmio);
> +       ahci_berlin_port_init(hpriv->mmio, nports);
> +
> +       ret = ahci_platform_init_host(pdev, hpriv, &ahci_berlin_port_info,
> +                                     force_map, 0);
> +       if (ret) {
> +               dev_err(dev, "host init failed: %d\n", ret);
> +               goto disable_resources;
> +       }
> +
> +       return 0;
> +
> +disable_resources:
> +       ahci_platform_disable_resources(hpriv);
> +       return ret;
> +}
> +
> +static const struct of_device_id ahci_berlin_of_match[] = {
> +       { .compatible = "marvell,berlin-ahci" },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(of, ahci_berlin_of_match);
> +
> +static struct platform_driver ahci_berlin_driver = {
> +       .probe  = ahci_berlin_probe,
> +       .remove = ata_platform_remove_one,
> +       .driver = {
> +               .name           = "ahci-berlin",
> +               .owner          = THIS_MODULE,
> +               .of_match_table = ahci_berlin_of_match,
> +       },
> +};
> +module_platform_driver(ahci_berlin_driver);
> +
> +MODULE_DESCRIPTION("Marvell Berlin AHCI SATA driver");
> +MODULE_AUTHOR("Antoine Ténart <antoine.tenart@free-electrons.com>");
> +MODULE_LICENSE("GPL");
> --
> 1.8.3.2
>
>
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