From f34f37160c2960a763ed05d1e13b2ea75a48d0fb Mon Sep 17 00:00:00 2001 From: Gupta Pekon Date: Fri, 31 May 2013 17:31:30 +0530 Subject: ARM: OMAP2+: gpmc: get number of useable GPMC chip-selects via DT This patch enables usage of DT property 'gpmc,num-cs' as already documented in Documentation/devicetree/bindings/bus/ti-gpmc.txt Though GPMC hardware supports upto 8 chip-selects, but all chip-selects may not be available for use because: - chip-select pin may not be bonded out at SoC device boundary. - chip-select pin-mux may conflict with other pins usage. - board level constrains. gpmc,num-cs allows user to configure maximum number of GPMC chip-selects available for use on any given platform. This ensures: - GPMC child nodes having chip-selects within allowed range are only probed. - And un-used GPMC chip-selects remain blocked.(may be for security reasons). Signed-off-by: Gupta, Pekon Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/gpmc.c | 38 +++++++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 9 deletions(-) (limited to 'arch/arm/mach-omap2') diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index 70d11ce..21b9636 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -155,6 +155,7 @@ static struct resource gpmc_cs_mem[GPMC_CS_NUM]; static DEFINE_SPINLOCK(gpmc_mem_lock); /* Define chip-selects as reserved by default until probe completes */ static unsigned int gpmc_cs_map = ((1 << GPMC_CS_NUM) - 1); +static unsigned int gpmc_cs_num = GPMC_CS_NUM; static unsigned int gpmc_nr_waitpins; static struct device *gpmc_dev; static int gpmc_irq; @@ -521,8 +522,10 @@ static int gpmc_cs_remap(int cs, u32 base) int ret; u32 old_base, size; - if (cs > GPMC_CS_NUM) + if (cs > gpmc_cs_num) { + pr_err("%s: requested chip-select is disabled\n", __func__); return -ENODEV; + } gpmc_cs_get_memconf(cs, &old_base, &size); if (base == old_base) return 0; @@ -545,9 +548,10 @@ int gpmc_cs_request(int cs, unsigned long size, unsigned long *base) struct resource *res = &gpmc_cs_mem[cs]; int r = -1; - if (cs > GPMC_CS_NUM) + if (cs > gpmc_cs_num) { + pr_err("%s: requested chip-select is disabled\n", __func__); return -ENODEV; - + } size = gpmc_mem_align(size); if (size > (1 << GPMC_SECTION_SHIFT)) return -ENOMEM; @@ -582,7 +586,7 @@ EXPORT_SYMBOL(gpmc_cs_request); void gpmc_cs_free(int cs) { spin_lock(&gpmc_mem_lock); - if (cs >= GPMC_CS_NUM || cs < 0 || !gpmc_cs_reserved(cs)) { + if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) { printk(KERN_ERR "Trying to free non-reserved GPMC CS%d\n", cs); BUG(); spin_unlock(&gpmc_mem_lock); @@ -777,7 +781,7 @@ static void gpmc_mem_exit(void) { int cs; - for (cs = 0; cs < GPMC_CS_NUM; cs++) { + for (cs = 0; cs < gpmc_cs_num; cs++) { if (!gpmc_cs_mem_enabled(cs)) continue; gpmc_cs_delete_mem(cs); @@ -798,7 +802,7 @@ static void gpmc_mem_init(void) gpmc_mem_root.end = GPMC_MEM_END; /* Reserve all regions that has been set up by bootloader */ - for (cs = 0; cs < GPMC_CS_NUM; cs++) { + for (cs = 0; cs < gpmc_cs_num; cs++) { u32 base, size; if (!gpmc_cs_mem_enabled(cs)) @@ -1526,6 +1530,20 @@ static int gpmc_probe_dt(struct platform_device *pdev) if (!of_id) return 0; + ret = of_property_read_u32(pdev->dev.of_node, "gpmc,num-cs", + &gpmc_cs_num); + if (ret < 0) { + pr_err("%s: number of chip-selects not defined\n", __func__); + return ret; + } else if (gpmc_cs_num < 1) { + pr_err("%s: all chip-selects are disabled\n", __func__); + return -EINVAL; + } else if (gpmc_cs_num > GPMC_CS_NUM) { + pr_err("%s: number of supported chip-selects cannot be > %d\n", + __func__, GPMC_CS_NUM); + return -EINVAL; + } + ret = of_property_read_u32(pdev->dev.of_node, "gpmc,num-waitpins", &gpmc_nr_waitpins); if (ret < 0) { @@ -1623,8 +1641,10 @@ static int gpmc_probe(struct platform_device *pdev) /* Now the GPMC is initialised, unreserve the chip-selects */ gpmc_cs_map = 0; - if (!pdev->dev.of_node) + if (!pdev->dev.of_node) { + gpmc_cs_num = GPMC_CS_NUM; gpmc_nr_waitpins = GPMC_NR_WAITPINS; + } rc = gpmc_probe_dt(pdev); if (rc < 0) { @@ -1728,7 +1748,7 @@ void omap3_gpmc_save_context(void) gpmc_context.prefetch_config1 = gpmc_read_reg(GPMC_PREFETCH_CONFIG1); gpmc_context.prefetch_config2 = gpmc_read_reg(GPMC_PREFETCH_CONFIG2); gpmc_context.prefetch_control = gpmc_read_reg(GPMC_PREFETCH_CONTROL); - for (i = 0; i < GPMC_CS_NUM; i++) { + for (i = 0; i < gpmc_cs_num; i++) { gpmc_context.cs_context[i].is_valid = gpmc_cs_mem_enabled(i); if (gpmc_context.cs_context[i].is_valid) { gpmc_context.cs_context[i].config1 = @@ -1760,7 +1780,7 @@ void omap3_gpmc_restore_context(void) gpmc_write_reg(GPMC_PREFETCH_CONFIG1, gpmc_context.prefetch_config1); gpmc_write_reg(GPMC_PREFETCH_CONFIG2, gpmc_context.prefetch_config2); gpmc_write_reg(GPMC_PREFETCH_CONTROL, gpmc_context.prefetch_control); - for (i = 0; i < GPMC_CS_NUM; i++) { + for (i = 0; i < gpmc_cs_num; i++) { if (gpmc_context.cs_context[i].is_valid) { gpmc_cs_write_reg(i, GPMC_CS_CONFIG1, gpmc_context.cs_context[i].config1); -- cgit v1.1