On 08/25/2014 09:50 PM, Tony Lindgren wrote:
> * Roger Quadros <rogerq@xxxxxx> [140825 04:27]:
>> From: Pekon Gupta <pekon@xxxxxx>
>>
>> Each GPMC chip-select needs to be configured for (base-address,CS-size) so that
>> GPMC understands the address-space allocated to device connected externally.
>> These chip-select configurations (base-address, CS-size) follow some basic
>> mapping rules like:
>> - The CS size is programmable from 256 MBytes to 16 MBytes (must be a power of 2)
>> and is defined by the mask field. Attached memory smaller than the programmed
>> CS region size is accessed through the entire CS region (aliasing).
>> - The programmed 'base-address' must be aligned to the 'CS-size' boundary and
>> be a power of 2.
>> - Valid CS-size values are {256MB(max), 128MB, 64MB, 32MB and 16MB (min)}
>> Any intermediate values creates holes in the chip-select memory-map.
>>
>> This patch adds above checks in gpmc_cs_remap() so that any invalid value
>> passed by DT <reg> property can be filtered before actually allocating the
>> address space.
>
> There's now an issue here where it mixes up the configured CS
> size and the configured device IO size. With this patch GPMC based
> Ethernet devices trigger warning at arch/arm/mach-omap2/gpmc.c:556
> as we have the minimal GPMC CS range of 16MB with the smsc IO size
> being either 0xf or 0xff depending on the model.
>
> So that check should be done on the CS size, not the device IO size.
>
Good catch.
This patch does not address the following issues from long term point of view
- The remap should be done not only for NOR/Ethernet devices but for all the
GPMC child nodes.
- The base address/size should be taken from the reg property
of the GPMC node and not of the child node as done in this patch.
Please drop this patch. I will include this in the clean up series which
I will post once ready. Currently I'm caught up with bug fixing and settling on
a stable version of GPMC which works on all boards that I have.
cheers,
-roger
> Regards,
>
> Tony
>
>> [rogerq@xxxxxx] typo and print message fixes.
>>
>> Signed-off-by: Pekon Gupta <pekon@xxxxxx>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> arch/arm/mach-omap2/gpmc.c | 51 +++++++++++++++++++++++++++++++++-------------
>> 1 file changed, 37 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
>> index 8bc1338..793f3a9 100644
>> --- a/arch/arm/mach-omap2/gpmc.c
>> +++ b/arch/arm/mach-omap2/gpmc.c
>> @@ -516,31 +516,54 @@ static int gpmc_cs_delete_mem(int cs)
>> * gpmc_cs_remap - remaps a chip-select physical base address
>> * @cs: chip-select to remap
>> * @base: physical base address to re-map chip-select to
>> + * @size: size of the chip select map
>> *
>> * Re-maps a chip-select to a new physical base address specified by
>> * "base". Returns 0 on success and appropriate negative error code
>> - * on failure.
>> + * on failure. "size" of the map must be either 16M, 32M, 64M or 128M.
>> */
>> -static int gpmc_cs_remap(int cs, u32 base)
>> +static int gpmc_cs_remap(int cs, u32 base, u32 size)
>> {
>> int ret;
>> - u32 old_base, size;
>>
>> if (cs > gpmc_cs_num) {
>> pr_err("%s: requested chip-select is disabled\n", __func__);
>> return -ENODEV;
>> }
>>
>> - /*
>> - * Make sure we ignore any device offsets from the GPMC partition
>> - * allocated for the chip select and that the new base confirms
>> - * to the GPMC 16MB minimum granularity.
>> - */
>> - base &= ~(SZ_16M - 1);
>> -
>> - gpmc_cs_get_memconf(cs, &old_base, &size);
>> - if (base == old_base)
>> - return 0;
>> + /* Align size to meet SoC limitations */
>> + if (size > SZ_256M) {
>> + pr_err("%s: CS memory map > 256MB not supported\n", __func__);
>> + return -ENODEV;
>> + } else if (size > SZ_128M) {
>> + WARN((size != SZ_256M), "%s: cs=%d: allocating 256MB\n",
>> + __func__, cs);
>> + size = SZ_256M;
>> + } else if (size > SZ_64M) {
>> + WARN((size != SZ_128M), "%s: cs=%d: allocating 128MB\n",
>> + __func__, cs);
>> + size = SZ_128M;
>> + } else if (size > SZ_32M) {
>> + WARN((size != SZ_64M), "%s: cs=%d: allocating 64MB\n",
>> + __func__, cs);
>> + size = SZ_64M;
>> + } else if (size > SZ_16M) {
>> + WARN((size != SZ_32M), "%s: cs=%d: allocating 32MB\n",
>> + __func__, cs);
>> + size = SZ_32M;
>> + } else {
>> + WARN((size != SZ_16M), "%s: cs=%d: allocating 16MB\n",
>> + __func__, cs);
>> + size = SZ_16M;
>> + }
>> +
>> + /* base address should be aligned with address-space size */
>> + if (base & (size - 1)) {
>> + pr_err("%s: cs base-addr: %x should be aligned to cs size: %x",
>> + __func__, base, size);
>> + return -EINVAL;
>> + }
>> +
>> gpmc_cs_disable_mem(cs);
>> ret = gpmc_cs_delete_mem(cs);
>> if (ret < 0)
>> @@ -1551,7 +1574,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
>> * CS to this location. Once DT migration is complete should
>> * just make gpmc_cs_request() map a specific address.
>> */
>> - ret = gpmc_cs_remap(cs, res.start);
>> + ret = gpmc_cs_remap(cs, res.start, resource_size(&res));
>> if (ret < 0) {
>> dev_err(&pdev->dev, "cannot remap GPMC CS %d to %pa\n",
>> cs, &res.start);
>> --
>> 1.8.3.2
>>
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