On 10/23/24 10:00 AM, Krzysztof Kozlowski wrote: >>>>> I also cannot find any piece of code setting several of above, e.g. tx_base >>>> I'm not writing any SRAM configuration fields, these fields are used to >>>> read/retrive the channel parameters from SRAM. >>> I meany tx_base is always 0. Where is this property set? Ever? >> It's not zero. My assumption is it is set in the acpm firmware, but I > Where is any assignment to this member? In probe() you'll see that exynos_acpm->shmem is a pointer in SRAM to a struct exynos_acpm_shmem __iomem *shmem; Then in: static int exynos_acpm_chans_init() { struct exynos_acpm_shmem_chan __iomem *shmem_chans, *shmem_chan; struct exynos_acpm_shmem __iomem *shmem = exynos_acpm->shmem; ... shmem_chans = exynos_acpm_get_iomem_addr(exynos_acpm->sram_base, &shmem->chans); ... } shmem->chans is not initialized (or tx_base). I'm using its address in SRAM (&shmem->chans) which I then read it with readl_relaxed(). I guess one can do the same using offsetof: shmem_chans = readl_realaxed(shmem + offsetof(struct exynos_acpm_shmem, chans)); Thanks, ta