[U-Boot] [PATCH V8 4/9] EXYNOS5: DWMMC: Added FDT support for DWMMC

Amarendra Reddy amar.lavanuru at gmail.com
Wed Apr 10 08:13:54 CEST 2013


Hi Jaehoon,

Please find my responses below.

Thanks & Regards
Amarendra Reddy

On 9 April 2013 16:23, Jaehoon Chung <jh80.chung at samsung.com> wrote:

> On 04/03/2013 11:08 PM, Amar wrote:
> > This patch adds FDT support for DWMMC, by reading the DWMMC node data
> > from the device tree and initialising DWMMC channels as per data
> > obtained from the node.
> >
> > Signed-off-by: Vivek Gautam <gautam.vivek at samsung.com>
> > Signed-off-by: Amar <amarendra.xt at samsung.com>
> > Acked-by: Simon Glass <sjg at chromium.org>
> > ---
> > Changes since V1:
> >       1)Updated code to have same signature for the function
> >       exynos_dwmci_init() for both FDT and non-FDT versions.
> >       2)Updated code to pass device_id parameter to the function
> >       exynos5_mmc_set_clk_div() instead of index.
> >       3)Updated code to decode the value of "samsung,width" from FDT.
> >       4)Channel index is computed instead of getting from FDT.
> >
> > Changes since V2:
> >       1)Updation of commit message and resubmition of proper patch set.
> >
> > Changes since V3:
> >       1)Replaced the new function exynos5_mmc_set_clk_div() with the
> >       existing function set_mmc_clk(). set_mmc_clk() will do the purpose.
> >       2)Computation of FSYS block clock divisor (pre-ratio) is added.
> >
> > Changes since V4:
> >       1)Replaced "unsigned int exynos_dwmmc_init(int index, int
> bus_width)" with
> >       int exynos_dwmci_add_port(int, u32, inth, u32)
> >               i)exynos_dwmmc_add_port() will be used by non-FDT boards.
> >               ii)In FDT case, exynos_dwmmc_init(const void *blob) will
> use
> >               exynos_dwmmc_add_port() for every channel enabled in
> device node.
> >       2)Changed the computation method of mmc clock divisor.
> >       3)Updated exynos_dwmmc_init() to compute the 'clksel_val' within
> the function.
> >
> > Changes since V5:
> >       1)Updated in response to review comments and changed the mmc clock
> value
> >       from 50MHz to 52MHz.
> >
> > Changes since V6:
> >       No change.
> >
> > Changes since V7:
> >       No change.
> >
> >  arch/arm/include/asm/arch-exynos/dwmmc.h |  11 +--
> >  drivers/mmc/exynos_dw_mmc.c              | 127
> ++++++++++++++++++++++++++++---
> >  include/dwmmc.h                          |   3 +
> >  3 files changed, 124 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/arch-exynos/dwmmc.h
> b/arch/arm/include/asm/arch-exynos/dwmmc.h
> > index 8acdf9b..3b147b8 100644
> > --- a/arch/arm/include/asm/arch-exynos/dwmmc.h
> > +++ b/arch/arm/include/asm/arch-exynos/dwmmc.h
> > @@ -27,10 +27,7 @@
> >  #define DWMCI_SET_DRV_CLK(x) ((x) << 16)
> >  #define DWMCI_SET_DIV_RATIO(x)       ((x) << 24)
> >
> > -int exynos_dwmci_init(u32 regbase, int bus_width, int index);
> > -
> > -static inline unsigned int exynos_dwmmc_init(int index, int bus_width)
> > -{
> > -     unsigned int base = samsung_get_base_mmc() + (0x10000 * index);
> > -     return exynos_dwmci_init(base, bus_width, index);
> > -}
> > +#ifdef CONFIG_OF_CONTROL
> > +int exynos_dwmmc_init(const void *blob);
> > +#endif
> > +int exynos_dwmci_add_port(int index, u32 regbase, int bus_width, u32
> clksel);
> > diff --git a/drivers/mmc/exynos_dw_mmc.c b/drivers/mmc/exynos_dw_mmc.c
> > index 72a31b7..4238dd9 100644
> > --- a/drivers/mmc/exynos_dw_mmc.c
> > +++ b/drivers/mmc/exynos_dw_mmc.c
> > @@ -19,39 +19,146 @@
> >   */
> >
> >  #include <common.h>
> > -#include <malloc.h>
> >  #include <dwmmc.h>
> > +#include <fdtdec.h>
> > +#include <libfdt.h>
> > +#include <malloc.h>
> >  #include <asm/arch/dwmmc.h>
> >  #include <asm/arch/clk.h>
> > +#include <asm/arch/pinmux.h>
> >
> > -static char *EXYNOS_NAME = "EXYNOS DWMMC";
> > +#define      DWMMC_MAX_CH_NUM                4
> > +#define      DWMMC_MAX_FREQ                  52000000
> > +#define      DWMMC_MIN_FREQ                  400000
> > +#define      DWMMC_MMC0_CLKSEL_VAL           0x03030001
> > +#define      DWMMC_MMC2_CLKSEL_VAL           0x03020001
> I known that CLKSEL's value is SoC specific.
> All exynos series are working fine? I didn't think so.
>
> Best Regards,
> Jaehoon Chung
>

The above values of CLKSEL work fine for Exynos5 (5250 & 5410) and is
tested.

The above CLKSEL values donot hold good for Exynos4 series. Exynos4 has
"Mobile Storage Host" with only one port.
But this file 'drivers/mmc/exynos_dw_mmc.c' is specific to Exynos5 series
and gets compiled only when CONFIG_EXYNOS_DWMMC is defined.

>
> > +/*
> > + * Function used as callback function to initialise the
> > + * CLKSEL register for every mmc channel.
> > + */
> >  static void exynos_dwmci_clksel(struct dwmci_host *host)
> >  {
> > -     u32 val;
> > -     val = DWMCI_SET_SAMPLE_CLK(DWMCI_SHIFT_0) |
> > -             DWMCI_SET_DRV_CLK(DWMCI_SHIFT_0) | DWMCI_SET_DIV_RATIO(0);
> > +     dwmci_writel(host, DWMCI_CLKSEL, host->clksel_val);
> > +}
> >
> > -     dwmci_writel(host, DWMCI_CLKSEL, val);
> > +unsigned int exynos_dwmci_get_clk(int dev_index)
> > +{
> > +     return get_mmc_clk(dev_index);
> >  }
> >
> > -int exynos_dwmci_init(u32 regbase, int bus_width, int index)
> > +/*
> > + * This function adds the mmc channel to be registered with mmc core.
> > + * index -   mmc channel number.
> > + * regbase - register base address of mmc channel specified in 'index'.
> > + * bus_width -       operating bus width of mmc channel specified in
> 'index'.
> > + * clksel -  value to be written into CLKSEL register in case of FDT.
> > + *           NULL in case od non-FDT.
> > + */
> > +int exynos_dwmci_add_port(int index, u32 regbase, int bus_width, u32
> clksel)
> >  {
> >       struct dwmci_host *host = NULL;
> > +     unsigned int div;
> > +     unsigned long freq, sclk;
> >       host = malloc(sizeof(struct dwmci_host));
> >       if (!host) {
> >               printf("dwmci_host malloc fail!\n");
> >               return 1;
> >       }
> > +     /* request mmc clock vlaue of 52MHz.  */
> > +     freq = 52000000;
> > +     sclk = get_mmc_clk(index);
> > +     div = DIV_ROUND_UP(sclk, freq);
> > +     /* set the clock divisor for mmc */
> > +     set_mmc_clk(index, div);
> >
> > -     host->name = EXYNOS_NAME;
> > +     host->name = "EXYNOS DWMMC";
> >       host->ioaddr = (void *)regbase;
> >       host->buswidth = bus_width;
> > +
> > +     if (clksel) {
> > +             host->clksel_val = clksel;
> > +     } else {
> > +             if (0 == index)
> > +                     host->clksel_val = DWMMC_MMC0_CLKSEL_VAL;
> > +             if (2 == index)
> > +                     host->clksel_val = DWMMC_MMC2_CLKSEL_VAL;
> > +     }
> > +
> >       host->clksel = exynos_dwmci_clksel;
> >       host->dev_index = index;
> > +     host->mmc_clk = exynos_dwmci_get_clk;
> > +     /* Add the mmc channel to be registered with mmc core */
> > +     if (add_dwmci(host, DWMMC_MAX_FREQ, DWMMC_MIN_FREQ)) {
> > +             debug("dwmmc%d registration failed\n", index);
> > +             return -1;
> > +     }
> > +     return 0;
> > +}
> > +
> > +#ifdef CONFIG_OF_CONTROL
> > +int exynos_dwmmc_init(const void *blob)
> > +{
> > +     int index, bus_width;
> > +     int node_list[DWMMC_MAX_CH_NUM];
> > +     int err = 0, dev_id, flag, count, i;
> > +     u32 clksel_val, base, timing[3];
> > +
> > +     count = fdtdec_find_aliases_for_id(blob, "mmc",
> > +                             COMPAT_SAMSUNG_EXYNOS5_DWMMC, node_list,
> > +                             DWMMC_MAX_CH_NUM);
> > +
> > +     for (i = 0; i < count; i++) {
> > +             int node = node_list[i];
> > +
> > +             if (node <= 0)
> > +                     continue;
> >
> > -     add_dwmci(host, 52000000, 400000);
> > +             /* Extract device id for each mmc channel */
> > +             dev_id = pinmux_decode_periph_id(blob, node);
> >
> > +             /* Get the bus width from the device node */
> > +             bus_width = fdtdec_get_int(blob, node,
> "samsung,bus-width", 0);
> > +             if (bus_width <= 0) {
> > +                     debug("DWMMC: Can't get bus-width\n");
> > +                     return -1;
> > +             }
> > +             if (8 == bus_width)
> > +                     flag = PINMUX_FLAG_8BIT_MODE;
> > +             else
> > +                     flag = PINMUX_FLAG_NONE;
> > +
> > +             /* config pinmux for each mmc channel */
> > +             err = exynos_pinmux_config(dev_id, flag);
> > +             if (err) {
> > +                     debug("DWMMC not configured\n");
> > +                     return err;
> > +             }
> > +
> > +             index = dev_id - PERIPH_ID_SDMMC0;
> > +
> > +             /* Get the base address from the device node */
> > +             base = fdtdec_get_addr(blob, node, "reg");
> > +             if (!base) {
> > +                     debug("DWMMC: Can't get base address\n");
> > +                     return -1;
> > +             }
> > +             /* Extract the timing info from the node */
> > +             err = fdtdec_get_int_array(blob, node, "samsung,timing",
> > +                                     timing, 3);
> > +             if (err) {
> > +                     debug("Can't get sdr-timings for divider\n");
> > +                     return -1;
> > +             }
> > +
> > +             clksel_val = (DWMCI_SET_SAMPLE_CLK(timing[0]) |
> > +                             DWMCI_SET_DRV_CLK(timing[1]) |
> > +                             DWMCI_SET_DIV_RATIO(timing[2]));
> > +             /* Initialise each mmc channel */
> > +             err = exynos_dwmci_add_port(index, base, bus_width,
> clksel_val);
> > +             if (err)
> > +                     debug("dwmmc Channel-%d init failed\n", index);
> > +     }
> >       return 0;
> >  }
> > -
> > +#endif
> > diff --git a/include/dwmmc.h b/include/dwmmc.h
> > index c8b1d40..e142f3e 100644
> > --- a/include/dwmmc.h
> > +++ b/include/dwmmc.h
> > @@ -123,6 +123,8 @@
> >  #define MSIZE(x)             ((x) << 28)
> >  #define RX_WMARK(x)          ((x) << 16)
> >  #define TX_WMARK(x)          (x)
> > +#define RX_WMARK_SHIFT               16
> > +#define RX_WMARK_MASK                (0xfff << RX_WMARK_SHIFT)
> >
> >  #define DWMCI_IDMAC_OWN              (1 << 31)
> >  #define DWMCI_IDMAC_CH               (1 << 4)
> > @@ -144,6 +146,7 @@ struct dwmci_host {
> >       unsigned int bus_hz;
> >       int dev_index;
> >       int buswidth;
> > +     u32 clksel_val;
> >       u32 fifoth_val;
> >       struct mmc *mmc;
> >
> >
>
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