[U-Boot] [PATCH V3 2/4] ARM: mx6: Add PCI express clock configuration

[Jagan Teki]

On Sat, Dec 14, 2013 at 10:57 AM, Marek Vasut <marex at denx.de> wrote:
> Split the SATA clock enabling function and add PCI express clock
> enabling function. The SATA clock enabling function starts up the
> 100MHz SATA reference PLL in ENET_PLL register, but the code can
> be re-used to enable the 125MHz PCIe reference in ENET_PLL, so pull
> this code into separate function. Moreover, add the PCIe clock
> enabling code.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Albert Aribaud <albert.u.boot at aribaud.net>
> Cc: Eric Nelson <eric.nelson at boundarydevices.com>
> Cc: Fabio Estevam <fabio.estevam at freescale.com>
> Cc: Stefano Babic <sbabic at denx.de>
> ---
>  arch/arm/cpu/armv7/mx6/clock.c        | 75 ++++++++++++++++++++++++++++++-----
>  arch/arm/include/asm/arch-mx6/clock.h |  1 +
>  2 files changed, 66 insertions(+), 10 deletions(-)
>
> V2: Drop the clock teardown function, it is not needed. Instead, fix a patch
>     for the Linux kernel to handle running link.
> V3: Fix some legacy coding style
>
> diff --git a/arch/arm/cpu/armv7/mx6/clock.c b/arch/arm/cpu/armv7/mx6/clock.c
> index 873d9d0..b25a954 100644
> --- a/arch/arm/cpu/armv7/mx6/clock.c
> +++ b/arch/arm/cpu/armv7/mx6/clock.c
> @@ -404,17 +404,12 @@ u32 imx_get_fecclk(void)
>         return decode_pll(PLL_ENET, MXC_HCLK);
>  }
>
> -int enable_sata_clock(void)
> +static int enable_enet_pll(uint32_t en)
>  {
> -       u32 reg = 0;
> -       s32 timeout = 100000;
>         struct mxc_ccm_reg *const imx_ccm
>                 = (struct mxc_ccm_reg *) CCM_BASE_ADDR;
> -
> -       /* Enable sata clock */
> -       reg = readl(&imx_ccm->CCGR5); /* CCGR5 */
> -       reg |= MXC_CCM_CCGR5_SATA_MASK;
> -       writel(reg, &imx_ccm->CCGR5);
> +       s32 timeout = 100000;
> +       u32 reg = 0;
>
>         /* Enable PLLs */
>         reg = readl(&imx_ccm->analog_pll_enet);
> @@ -429,10 +424,70 @@ int enable_sata_clock(void)
>                 return -EIO;
>         reg &= ~BM_ANADIG_PLL_SYS_BYPASS;
>         writel(reg, &imx_ccm->analog_pll_enet);
> -       reg |= BM_ANADIG_PLL_ENET_ENABLE_SATA;
> +       reg |= en;
>         writel(reg, &imx_ccm->analog_pll_enet);
> +       return 0;
> +}
>
> -       return 0 ;
> +static void ungate_sata_clock(void)
> +{
> +       struct mxc_ccm_reg *const imx_ccm =
> +               (struct mxc_ccm_reg *)CCM_BASE_ADDR;
> +
> +       /* Enable SATA clock. */
> +       setbits_le32(&imx_ccm->CCGR5, MXC_CCM_CCGR5_SATA_MASK);
> +}
> +
> +static void ungate_pcie_clock(void)
> +{
> +       struct mxc_ccm_reg *const imx_ccm =
> +               (struct mxc_ccm_reg *)CCM_BASE_ADDR;
> +
> +       /* Enable PCIe clock. */
> +       setbits_le32(&imx_ccm->CCGR4, MXC_CCM_CCGR4_PCIE_MASK);
> +}
> +
> +int enable_sata_clock(void)
> +{
> +       ungate_sata_clock();
> +       return enable_enet_pll(BM_ANADIG_PLL_ENET_ENABLE_SATA);
> +}
> +
> +int enable_pcie_clock(void)
> +{
> +       struct anatop_regs *anatop_regs =
> +               (struct anatop_regs *)ANATOP_BASE_ADDR;
> +       struct mxc_ccm_reg *ccm_regs = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
> +
> +       /*
> +        * Here be dragons!
> +        *
> +        * The register ANATOP_MISC1 is not documented in the Freescale
> +        * MX6RM. The register that is mapped in the ANATOP space and
> +        * marked as ANATOP_MISC1 is actually documented in the PMU section
> +        * of the datasheet as PMU_MISC1.
> +        *
> +        * Switch LVDS clock source to SATA (0xb), disable clock INPUT and
> +        * enable clock OUTPUT. This is important for PCI express link that
> +        * is clocked from the i.MX6.
> +        */
> +#define ANADIG_ANA_MISC1_LVDSCLK1_IBEN         (1 << 12)
> +#define ANADIG_ANA_MISC1_LVDSCLK1_OBEN         (1 << 10)
> +#define ANADIG_ANA_MISC1_LVDS1_CLK_SEL_MASK    0x0000001F
> +       clrsetbits_le32(&anatop_regs->ana_misc1,
> +                       ANADIG_ANA_MISC1_LVDSCLK1_IBEN |
> +                       ANADIG_ANA_MISC1_LVDS1_CLK_SEL_MASK,
> +                       ANADIG_ANA_MISC1_LVDSCLK1_OBEN | 0xb);
> +
> +       /* PCIe reference clock sourced from AXI. */
> +       clrbits_le32(&ccm_regs->cbcmr, MXC_CCM_CBCMR_PCIE_AXI_CLK_SEL);
> +
> +       /* Party time! Ungate the clock to the PCIe. */
> +       ungate_sata_clock();
> +       ungate_pcie_clock();
> +
> +       return enable_enet_pll(BM_ANADIG_PLL_ENET_ENABLE_SATA |
> +                              BM_ANADIG_PLL_ENET_ENABLE_PCIE);
>  }
>
>  unsigned int mxc_get_clock(enum mxc_clock clk)
> diff --git a/arch/arm/include/asm/arch-mx6/clock.h b/arch/arm/include/asm/arch-mx6/clock.h
> index 93f29a7..95b1270 100644
> --- a/arch/arm/include/asm/arch-mx6/clock.h
> +++ b/arch/arm/include/asm/arch-mx6/clock.h
> @@ -48,6 +48,7 @@ unsigned int mxc_get_clock(enum mxc_clock clk);
>  void enable_ocotp_clk(unsigned char enable);
>  void enable_usboh3_clk(unsigned char enable);
>  int enable_sata_clock(void);
> +int enable_pcie_clock(void);
>  int enable_i2c_clk(unsigned char enable, unsigned i2c_num);
>  void enable_ipu_clock(void);
>  int enable_fec_anatop_clock(void);

Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>

-- 
Thanks,
Jagan.
--------
Jagannadha Sutradharudu Teki,
E: jagannadh.teki at gmail.com, P: +91-9676773388
Engineer - System Software Hacker
U-boot - SPI Custodian and Zynq APSOC
Ln: http://www.linkedin.com/in/jaganteki