Re: [PATCH 1/1] hw: aspeed_gpio: Fix GPIO array indexing

[Peter Delevoryas]

> On Sep 25, 2021, at 4:03 AM, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> 
> Hi Peter,
> 
>> On 9/24/21 08:19, pdel@fb.com wrote:
>> From: Peter Delevoryas <pdel@fb.com>
>> The gpio array is declared as a dense array:
>> ...
>> qemu_irq gpios[ASPEED_GPIO_NR_PINS];
>> (AST2500 has 228, AST2400 has 216, AST2600 has 208)
>> However, this array is used like a matrix of GPIO sets
>> (e.g. gpio[NR_SETS][NR_PINS_PER_SET] = gpio[8][32])
>> size_t offset = set * GPIOS_PER_SET + gpio;
>> qemu_set_irq(s->gpios[offset], !!(new & mask));
>> This can result in an out-of-bounds access to "s->gpios" because the
>> gpio sets do _not_ have the same length. Some of the groups (e.g.
>> GPIOAB) only have 4 pins. 228 != 8 * 32 == 256.
>> To fix this, I converted the gpio array from dense to sparse, to that
>> match both the hardware layout and this existing indexing code.
> 
> This is one logical change: 1 patch
> 
>> Also, I noticed that some of the property specifications looked wrong:
>> the lower 8 bits in the input and output u32's correspond to the first
>> group label, and the upper 8 bits correspond to the last group label.
> 
> Another logical change: another patch :)
> 
> So please split this patch in 2. Maybe easier to fix GPIOSetProperties
> first, then convert from dense to sparse array.
> 

Good point, I’ll split it up then!

> Regards,
> 
> Phil.
> 
>> I looked at the datasheet and several of these declarations seemed
>> incorrect to me (I was basing it off of the I/O column). If somebody
>> can double-check this, I'd really appreciate it!
>> Some were definitely wrong though, like "Y" and "Z" in the 2600.
>> @@ -796,7 +776,7 @@ static const GPIOSetProperties ast2500_set_props[] = {
>>      [3] = {0xffffffff,  0xffffffff,  {"M", "N", "O", "P"} },
>>      [4] = {0xffffffff,  0xffffffff,  {"Q", "R", "S", "T"} },
>>      [5] = {0xffffffff,  0x0000ffff,  {"U", "V", "W", "X"} },
>> -    [6] = {0xffffff0f,  0x0fffff0f,  {"Y", "Z", "AA", "AB"} },
>> +    [6] = {0x0fffffff,  0x0fffffff,  {"Y", "Z", "AA", "AB"} },
>>      [7] = {0x000000ff,  0x000000ff,  {"AC"} },
>>  };
>> @@ -805,9 +785,9 @@ static GPIOSetProperties ast2600_3_3v_set_props[] = {
>>      [1] = {0xffffffff,  0xffffffff,  {"E", "F", "G", "H"} },
>>      [2] = {0xffffffff,  0xffffffff,  {"I", "J", "K", "L"} },
>>      [3] = {0xffffffff,  0xffffffff,  {"M", "N", "O", "P"} },
>> -    [4] = {0xffffffff,  0xffffffff,  {"Q", "R", "S", "T"} },
>> -    [5] = {0xffffffff,  0x0000ffff,  {"U", "V", "W", "X"} },
>> -    [6] = {0xffff0000,  0x0fff0000,  {"Y", "Z", "", ""} },
>> +    [4] = {0xffffffff,  0x00ffffff,  {"Q", "R", "S", "T"} },
>> +    [5] = {0xffffffff,  0xffffff00,  {"U", "V", "W", "X"} },
>> +    [6] = {0x0000ffff,  0x0000ffff,  {"Y", "Z", "", ""} },
>>  };
>> Signed-off-by: Peter Delevoryas <pdel@fb.com>
>> ---
>>  hw/gpio/aspeed_gpio.c         | 80 +++++++++++++++--------------------
>>  include/hw/gpio/aspeed_gpio.h |  5 +--
>>  2 files changed, 35 insertions(+), 50 deletions(-)