Re: [PATCH 05/13] ARM: MXS: i.MX28: add autodetection of memory banks

[Roland Hieber <r.hieber@pengutronix.de>]

On Wed, Jul 25, 2018 at 03:36:10PM +0200, Roland Hieber wrote:
> If the prebootloader has set up the EMI controller correctly, we can
> autodetect the size of available RAM by looking at the respective
> configuration registers.
> 
> Signed-off-by: Roland Hieber <r.hieber@pengutronix.de>
> ---
>  arch/arm/mach-mxs/Makefile    |  2 +-
>  arch/arm/mach-mxs/mem-imx28.c | 39 +++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+), 1 deletion(-)
>  create mode 100644 arch/arm/mach-mxs/mem-imx28.c
> 
> diff --git a/arch/arm/mach-mxs/Makefile b/arch/arm/mach-mxs/Makefile
> index e3843368c2..0761f909a1 100644
> --- a/arch/arm/mach-mxs/Makefile
> +++ b/arch/arm/mach-mxs/Makefile
> @@ -1,7 +1,7 @@
>  obj-y += imx.o iomux-imx.o power.o
>  pbl-y += iomux-imx.o
>  obj-$(CONFIG_ARCH_IMX23) += clocksource-imx23.o usb-imx23.o soc-imx23.o
> -obj-$(CONFIG_ARCH_IMX28) += clocksource-imx28.o usb-imx28.o soc-imx28.o
> +obj-$(CONFIG_ARCH_IMX28) += clocksource-imx28.o usb-imx28.o soc-imx28.o mem-imx28.o
>  obj-$(CONFIG_MXS_OCOTP) += ocotp.o
>  obj-$(CONFIG_MXS_CMD_BCB) += bcb.o
>  pbl-y += power-init.o mem-init.o lradc-init.o
> diff --git a/arch/arm/mach-mxs/mem-imx28.c b/arch/arm/mach-mxs/mem-imx28.c
> new file mode 100644
> index 0000000000..e827e0906f
> --- /dev/null
> +++ b/arch/arm/mach-mxs/mem-imx28.c
> @@ -0,0 +1,39 @@
> +/*
> + * Copyright (C) 2018 Pengutronix, Roland Hieber <r.hieber@pengutronix.de>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that 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.
> + */
> +
> +#include <init.h>
> +#include <asm/memory.h>
> +#include <mach/imx28-regs.h>
> +#include <printk.h>

Mhm, there are some includes missing. Will fix in v2.

 - Roland

> +
> +static int mx28_add_mem(void)
> +{
> +	if (!of_machine_is_compatible("fsl,imx28"))
> +		return 0;
> +
> +	int * sdramc = (int *)IMX_SDRAMC_BASE;
> +
> +	uint8_t columns = 12 - ((sdramc[29] >> 16) & 0b111);
> +	uint8_t rows    = 15 - ((sdramc[29] >>  8) & 0b111);
> +	uint8_t banks   =      ((sdramc[31] >> 16) & 0b1)  ?  8  :  4;
> +	uint8_t width   = sizeof (unsigned short);
> +
> +	uint32_t size = (1 << columns) * (1 << rows) * banks * width;
> +	pr_info("i.MX28: detected %d cols, %d rows, %d banks = %d MiB of RAM\n",
> +			columns, rows, banks, size / 1024 / 1024);
> +
> +	arm_add_mem_device("ram0", IMX_MEMORY_BASE, size);
> +
> +	return 0;
> +}
> +mem_initcall(mx28_add_mem);
> -- 
> 2.18.0
> 
> 
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-- 
Roland Hieber                     | r.hieber@pengutronix.de     |
Pengutronix e.K.                  | https://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim | Phone: +49-5121-206917-5086 |
Amtsgericht Hildesheim, HRA 2686  | Fax:   +49-5121-206917-5555 |

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