From aaa63093dd4c393391a3368e1c7305b0cc620571 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Thu, 29 Aug 2013 16:55:45 +1000 Subject: [PATCH] powerpc/scom: Change scom_read() and scom_write() to return errors scom_read() now returns the read value via a pointer argument and both functions return an int error code Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/scom.h | 23 +++++++++++++++++------ arch/powerpc/platforms/wsp/scom_smp.c | 18 +++++++++++++----- arch/powerpc/platforms/wsp/scom_wsp.c | 12 ++++++++---- arch/powerpc/platforms/wsp/wsp.c | 13 +++++++------ arch/powerpc/sysdev/scom.c | 3 +-- 5 files changed, 46 insertions(+), 23 deletions(-) diff --git a/arch/powerpc/include/asm/scom.h b/arch/powerpc/include/asm/scom.h index 0cabfd7bc2d1..07dcdcfdaefc 100644 --- a/arch/powerpc/include/asm/scom.h +++ b/arch/powerpc/include/asm/scom.h @@ -54,8 +54,8 @@ struct scom_controller { scom_map_t (*map)(struct device_node *ctrl_dev, u64 reg, u64 count); void (*unmap)(scom_map_t map); - u64 (*read)(scom_map_t map, u32 reg); - void (*write)(scom_map_t map, u32 reg, u64 value); + int (*read)(scom_map_t map, u32 reg, u64 *value); + int (*write)(scom_map_t map, u32 reg, u64 value); }; extern const struct scom_controller *scom_controller; @@ -133,10 +133,18 @@ static inline void scom_unmap(scom_map_t map) * scom_read - Read a SCOM register * @map: Result of scom_map * @reg: Register index within that map + * @value: Updated with the value read + * + * Returns 0 (success) or a negative error code */ -static inline u64 scom_read(scom_map_t map, u32 reg) +static inline int scom_read(scom_map_t map, u32 reg, u64 *value) { - return scom_controller->read(map, reg); + int rc; + + rc = scom_controller->read(map, reg, value); + if (rc) + *value = 0xfffffffffffffffful; + return rc; } /** @@ -144,12 +152,15 @@ static inline u64 scom_read(scom_map_t map, u32 reg) * @map: Result of scom_map * @reg: Register index within that map * @value: Value to write + * + * Returns 0 (success) or a negative error code */ -static inline void scom_write(scom_map_t map, u32 reg, u64 value) +static inline int scom_write(scom_map_t map, u32 reg, u64 value) { - scom_controller->write(map, reg, value); + return scom_controller->write(map, reg, value); } + #endif /* CONFIG_PPC_SCOM */ #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/platforms/wsp/scom_smp.c b/arch/powerpc/platforms/wsp/scom_smp.c index b56b70aeb497..268bc899c1f7 100644 --- a/arch/powerpc/platforms/wsp/scom_smp.c +++ b/arch/powerpc/platforms/wsp/scom_smp.c @@ -116,7 +116,14 @@ static int a2_scom_ram(scom_map_t scom, int thread, u32 insn, int extmask) scom_write(scom, SCOM_RAMIC, cmd); - while (!((val = scom_read(scom, SCOM_RAMC)) & mask)) { + for (;;) { + if (scom_read(scom, SCOM_RAMC, &val) != 0) { + pr_err("SCOM error on instruction 0x%08x, thread %d\n", + insn, thread); + return -1; + } + if (val & mask) + break; pr_devel("Waiting on RAMC = 0x%llx\n", val); if (++n == 3) { pr_err("RAMC timeout on instruction 0x%08x, thread %d\n", @@ -151,9 +158,7 @@ static int a2_scom_getgpr(scom_map_t scom, int thread, int gpr, int alt, if (rc) return rc; - *out_gpr = scom_read(scom, SCOM_RAMD); - - return 0; + return scom_read(scom, SCOM_RAMD, out_gpr); } static int a2_scom_getspr(scom_map_t scom, int thread, int spr, u64 *out_spr) @@ -353,7 +358,10 @@ int a2_scom_startup_cpu(unsigned int lcpu, int thr_idx, struct device_node *np) pr_devel("Bringing up CPU%d using SCOM...\n", lcpu); - pccr0 = scom_read(scom, SCOM_PCCR0); + if (scom_read(scom, SCOM_PCCR0, &pccr0) != 0) { + printk(KERN_ERR "XSCOM failure readng PCCR0 on CPU%d\n", lcpu); + return -1; + } scom_write(scom, SCOM_PCCR0, pccr0 | SCOM_PCCR0_ENABLE_DEBUG | SCOM_PCCR0_ENABLE_RAM); diff --git a/arch/powerpc/platforms/wsp/scom_wsp.c b/arch/powerpc/platforms/wsp/scom_wsp.c index 4052e2259f30..54172c4a8a64 100644 --- a/arch/powerpc/platforms/wsp/scom_wsp.c +++ b/arch/powerpc/platforms/wsp/scom_wsp.c @@ -50,18 +50,22 @@ static void wsp_scom_unmap(scom_map_t map) iounmap((void *)map); } -static u64 wsp_scom_read(scom_map_t map, u32 reg) +static int wsp_scom_read(scom_map_t map, u32 reg, u64 *value) { u64 __iomem *addr = (u64 __iomem *)map; - return in_be64(addr + reg); + *value = in_be64(addr + reg); + + return 0; } -static void wsp_scom_write(scom_map_t map, u32 reg, u64 value) +static int wsp_scom_write(scom_map_t map, u32 reg, u64 value) { u64 __iomem *addr = (u64 __iomem *)map; - return out_be64(addr + reg, value); + out_be64(addr + reg, value); + + return 0; } static const struct scom_controller wsp_scom_controller = { diff --git a/arch/powerpc/platforms/wsp/wsp.c b/arch/powerpc/platforms/wsp/wsp.c index d25cc96c21b8..ddb6efe88914 100644 --- a/arch/powerpc/platforms/wsp/wsp.c +++ b/arch/powerpc/platforms/wsp/wsp.c @@ -89,6 +89,7 @@ void wsp_halt(void) struct device_node *dn; struct device_node *mine; struct device_node *me; + int rc; me = of_get_cpu_node(smp_processor_id(), NULL); mine = scom_find_parent(me); @@ -101,15 +102,15 @@ void wsp_halt(void) /* read-modify-write it so the HW probe does not get * confused */ - val = scom_read(m, 0); - val |= 1; - scom_write(m, 0, val); + rc = scom_read(m, 0, &val); + if (rc == 0) + scom_write(m, 0, val | 1); scom_unmap(m); } m = scom_map(mine, 0, 1); - val = scom_read(m, 0); - val |= 1; - scom_write(m, 0, val); + rc = scom_read(m, 0, &val); + if (rc == 0) + scom_write(m, 0, val | 1); /* should never return */ scom_unmap(m); } diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/sysdev/scom.c index 9193e12df695..10f1d9e56612 100644 --- a/arch/powerpc/sysdev/scom.c +++ b/arch/powerpc/sysdev/scom.c @@ -137,8 +137,7 @@ static int scom_val_get(void *data, u64 *val) if (!scom_map_ok(ent->map)) return -EFAULT; - *val = scom_read(ent->map, 0); - return 0; + return scom_read(ent->map, 0, val); } DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set, "0x%llx\n"); -- 2.20.1