Hi Jon,
I'm working on a similar memory controller for plat-orion.
I have a few questions about your approach.
On Wed, Feb 13, 2013 at 03:07:06PM -0600, Jon Hunter wrote:
>
> On 02/07/2013 03:51 AM, Mark Jackson wrote:
> > Okay ... I have made some progress, but it's not ideal.
> >
> > Currently I've hacked the GPMC DT driver (gpmc_probe_dt(), etc) so it now
> > handles setting up the
> > chip selects and timings for NOR devices, e.g.
> >
> > gpmc: gpmc@50000000 {
> > status = "okay";
> > ranges = <0 0 0x08000000 0x08000000>; /* CS0: NOR 16M
> > */
>
> Is that really 16M? Looks more like 128M :-)
>
> > nor@0,0 {
> > compatible = "spansion,s29gl064n90t",
> > "cfi-flash";
> > reg = <0 0 0>;
>
> I think that cfi-flash is expecting a length here. Here is
> what I have ...
>
> +&gpmc {
> + ranges = <0 0 0x08000000 0x04000000>;
> +
> + nor@0,0 {
> + compatible = "cfi-flash";
> + linux,mtd-name= "intel,ge28f256l18b85";
> + #address-cells = <1>;
> + #size-cells = <1>;
> + reg = <0 0 0x04000000>;
> + bank-width = <2>;
> +
> + partition@0 {
> + label = "bootloader";
> + reg = <0 0x20000>;
> + };
> + partition@0x20000 {
> + label = "params";
> + reg = <0x20000 0x20000>;
> + };
> + partition@0x40000 {
> + label = "kernel";
> + reg = <0x40000 0x200000>;
> + };
> + partition@0x240000 {
> + label = "file-system";
> + reg = <0x240000 0x3dc0000>;
> + };
> + };
>
> > nor-flash@08000000 {
> > compatible = "spansion,s29gl064n90t", "cfi-flash";
> > reg = <0x08000000 0x00800000>;
> > bank-width = <2>;
> > };
>
> You don't need this extra entry if you add "simple-bus" to
> the gpmc node compatible string.
>
That would be nice. However, I wonder what happens if cfi-flash probing
fails: will the gpmc cs request by undone? See below...
> + gpmc: gpmc@6800a000 {
> + compatible = "ti,omap2420-gpmc", "simple-bus";
> + ti,hwmods = "gpmc";
> + reg = <0x6800a000 0x1000>;
> + interrupts = <20>;
> +
> + gpmc,num-cs = <8>;
> + gpmc,num-waitpins = <4>;
> + #address-cells = <2>;
> + #size-cells = <1>;
> + };
>
> Currently I have the following and this is working for me.
> Please note that on my board the bootloader is configuring
> the timings for me and so this is missing from the below
> implementation and still needs to be added.
>
> Cheers
> Jon
>
> From c0ede833fad704ab452b116154177e3a59166c7e Mon Sep 17 00:00:00 2001
> From: Jon Hunter <[email protected]>
> Date: Fri, 8 Feb 2013 16:46:13 -0600
> Subject: [PATCH] ARM: OMAP2+: Add device-tree support for NOR flash
>
> ---
> arch/arm/mach-omap2/gpmc.c | 69
> ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
> index bc90155..421320b 100644
> --- a/arch/arm/mach-omap2/gpmc.c
> +++ b/arch/arm/mach-omap2/gpmc.c
> @@ -26,6 +26,7 @@
> #include <linux/interrupt.h>
> #include <linux/platform_device.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> #include <linux/of_mtd.h>
> #include <linux/of_device.h>
> #include <linux/mtd/nand.h>
> @@ -517,6 +518,26 @@ static int gpmc_cs_delete_mem(int cs)
> return r;
> }
>
> +static int gpmc_cs_remap(int cs, u32 base)
> +{
> + int r;
> + u32 old_base, size;
> +
> + gpmc_cs_get_memconf(cs, &old_base, &size);
> + if (base == old_base)
> + return 0;
> + gpmc_cs_disable_mem(cs);
> + r = gpmc_cs_delete_mem(cs);
> + if (IS_ERR_VALUE(r))
> + return r;
> + r = gpmc_cs_insert_mem(cs, base, size);
> + if (IS_ERR_VALUE(r))
> + return r;
> + gpmc_cs_enable_mem(cs, base, size);
> +
> + return 0;
> +}
> +
> int gpmc_cs_request(int cs, unsigned long size, unsigned long *base)
> {
> struct resource *res = &gpmc_cs_mem[cs];
> @@ -1305,6 +1326,45 @@ static int gpmc_probe_onenand_child(struct
> platform_device *pdev,
> }
> #endif
>
> +static int gpmc_probe_nor_child(struct platform_device *pdev,
> + struct device_node *child)
> +{
> + struct resource res;
> + unsigned long base;
> + int rc, cs;
> +
> + if (of_property_read_u32(child, "reg", &cs) < 0) {
> + dev_err(&pdev->dev, "%s has no 'reg' property\n",
> + child->full_name);
> + return -ENODEV;
> + }
> +
> + if (of_address_to_resource(child, 0, &res)) {
> + dev_err(&pdev->dev, "%s has malformed 'reg' property\n",
> + child->full_name);
> + return -ENODEV;
> + }
> +
> + rc = gpmc_cs_request(cs, res.end - res.start, &base);
> + if (rc < 0)
> + pr_err("%s: cannot request GPMC CS %d\n", __func__, cs);
gpmc_cs_request will request a memory region from the resource allocator
using allocate_resource().
How will this be released in case cfi-flash probe fails?
IMHO, this works fine currently for NAND and OneNAND because we register
the platform device explicitly and, thus, know if that fails.
> +
> + /*
> + * gpmc_cs_request() will map the CS to an arbitary location
> + * in the gpmc address space. When booting with device-tree we
> + * want the NOR flash to be mapped to the location specified
> + * in the device-tree blob. So remap the CS to this location.
> + */
> + rc = gpmc_cs_remap(cs, res.start);
> + if (rc < 0) {
> + pr_err("%s: cannot remap GPMC CS %d to 0x%x\n",
> + __func__, cs, res.start);
> + gpmc_cs_free(cs);
> + }
> +
> + return rc;
> +}
> +
> static int gpmc_probe_dt(struct platform_device *pdev)
> {
> int ret;
> @@ -1330,6 +1390,15 @@ static int gpmc_probe_dt(struct platform_device *pdev)
> return ret;
> }
> }
> +
> + for_each_node_by_name(child, "nor") {
> + ret = gpmc_probe_nor_child(pdev, child);
> + if (ret < 0) {
> + of_node_put(child);
> + return ret;
> + }
> + }
> +
> return 0;
> }
> #else
> --
Thanks,
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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