On Tue, Jul 25, 2023 at 06:41:00PM +0200, Gatien Chevallier wrote: ... > diff --git a/drivers/bus/stm32_rifsc.c b/drivers/bus/stm32_rifsc.c ... > +static int stm32_rif_acquire_semaphore(struct stm32_firewall_controller *stm32_firewall_controller, > + int id) > +{ > + void __iomem *addr = stm32_firewall_controller->mmio + RIFSC_RISC_PER0_SEMCR + 0x8 * id; > + > + __set_bit(SEMCR_MUTEX, addr); Hi Gatien, Sparse seem a bit unhappy about this. .../stm32_rifsc.c:83:9: warning: cast removes address space '__iomem' of expression .../stm32_rifsc.c:83:9: warning: incorrect type in argument 2 (different address spaces) .../stm32_rifsc.c:83:9: expected unsigned long volatile *addr .../stm32_rifsc.c:83:9: got void [noderef] __iomem *addr .../stm32_rifsc.c:83:9: warning: incorrect type in argument 2 (different address spaces) .../stm32_rifsc.c:83:9: expected unsigned long volatile *addr .../stm32_rifsc.c:83:9: got void [noderef] __iomem *addr But it's not immediately apparent to me what a good solution is. > + > + /* Check that CID1 has the semaphore */ > + if (stm32_rifsc_is_semaphore_available(addr) || > + FIELD_GET(RIFSC_RISC_SCID_MASK, readl(addr)) != RIF_CID1) > + return -EACCES; > + > + return 0; > +} ...