[J-core] Building today's vanilla linux.
Rich Felker
dalias at libc.org
Mon Aug 15 21:57:32 EDT 2016
On Mon, Aug 15, 2016 at 06:04:06PM -0500, Rob Landley wrote:
> Now that -rc2 is out, I tried a test build a vanilla git snapshot using
> Rich's toolchain:
>
> make ARCH=sh CROSS_COMPILE=sh2eb-linux-muslfdpic- j2_defconfig
> make ARCH=sh CROSS_COMPILE=sh2eb-linux-muslfdpic- -j 3
>
> Copied the resulting vmlinux onto the sdcard, booted it, and it hung
> "calibrating delay loop". (I believe this is because the interrupt
> controller plumbing hasn't made it upstream yet?)
Yes, that's because it lacks timer and interrupt controller.
> What's the likelihood of that happening this release, and what's the
> patch still needed to make what's currently there work right?
I'm attaching a patchset with just the interrupt controller, timer,
and spi drivers. Strictly speaking spi is not needed but it's nice to
have. For the sake of simplicity I've omitted DT binding document
patches and such that aren't actually needed to run.
Rich
-------------- next part --------------
>From 18fdfcf452bb68f6c17f9ff527f21c8f05d7a152 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias at libc.org>
Date: Thu, 17 Mar 2016 23:12:12 +0000
Subject: [PATCH] irqchip: add J-Core AIC driver
There are two versions of the J-Core interrupt controller in use, aic1
which generates interrupts with programmable priorities, but only
supports 8 irq lines and maps them to cpu traps in the range 17 to 24,
and aic2 which uses traps in the range 64-127 and supports up to 128
irqs, with priorities dependent on the interrupt number. The Linux
driver does not make use of priorities anyway.
For simplicity, there is no aic1-specific logic in the driver beyond
setting the priority register, which is necessary for interrupts to
work at all. Eventually aic1 will likely be phased out, but it's
currently in use in deployments and all released bitstream binaries.
Signed-off-by: Rich Felker <dalias at libc.org>
---
drivers/irqchip/Kconfig | 7 +++
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-jcore-aic.c | 94 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 102 insertions(+)
create mode 100644 drivers/irqchip/irq-jcore-aic.c
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 5495a5b..ab84ce3 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -156,6 +156,13 @@ config PIC32_EVIC
select GENERIC_IRQ_CHIP
select IRQ_DOMAIN
+config JCORE_AIC
+ bool "J-Core integrated AIC"
+ depends on OF && (SUPERH || COMPILE_TEST)
+ select IRQ_DOMAIN
+ help
+ Support for the J-Core integrated AIC.
+
config RENESAS_INTC_IRQPIN
bool
select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 4c203b6..ee7e3ca 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_I8259) += irq-i8259.o
obj-$(CONFIG_IMGPDC_IRQ) += irq-imgpdc.o
obj-$(CONFIG_IRQ_MIPS_CPU) += irq-mips-cpu.o
obj-$(CONFIG_SIRF_IRQ) += irq-sirfsoc.o
+obj-$(CONFIG_JCORE_AIC) += irq-jcore-aic.o
obj-$(CONFIG_RENESAS_INTC_IRQPIN) += irq-renesas-intc-irqpin.o
obj-$(CONFIG_RENESAS_IRQC) += irq-renesas-irqc.o
obj-$(CONFIG_VERSATILE_FPGA_IRQ) += irq-versatile-fpga.o
diff --git a/drivers/irqchip/irq-jcore-aic.c b/drivers/irqchip/irq-jcore-aic.c
new file mode 100644
index 0000000..5e5e3bb
--- /dev/null
+++ b/drivers/irqchip/irq-jcore-aic.c
@@ -0,0 +1,94 @@
+/*
+ * J-Core SoC AIC driver
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define JCORE_AIC_MAX_HWIRQ 127
+#define JCORE_AIC1_MIN_HWIRQ 16
+#define JCORE_AIC2_MIN_HWIRQ 64
+
+#define JCORE_AIC1_INTPRI_REG 8
+
+static struct irq_chip jcore_aic;
+
+static int jcore_aic_irqdomain_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ struct irq_chip *aic = d->host_data;
+
+ irq_set_chip_and_handler(irq, aic, handle_simple_irq);
+
+ return 0;
+}
+
+static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
+ .map = jcore_aic_irqdomain_map,
+ .xlate = irq_domain_xlate_onecell,
+};
+
+static void noop(struct irq_data *data)
+{
+}
+
+int __init aic_irq_of_init(struct device_node *node, struct device_node *parent)
+{
+ unsigned min_irq = JCORE_AIC2_MIN_HWIRQ;
+ unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1;
+ struct irq_domain *domain;
+
+ pr_info("Initializing J-Core AIC\n");
+
+ /* AIC1 needs priority initialization to receive interrupts. */
+ if (of_device_is_compatible(node, "jcore,aic1")) {
+ unsigned cpu;
+
+ for_each_present_cpu(cpu) {
+ void __iomem *base = of_iomap(node, cpu);
+
+ if (!base) {
+ pr_err("Unable to map AIC for cpu %u\n", cpu);
+ return -ENOMEM;
+ }
+ __raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
+ iounmap(base);
+ }
+ min_irq = JCORE_AIC1_MIN_HWIRQ;
+ }
+
+ /*
+ * The irq chip framework requires either mask/unmask or enable/disable
+ * function pointers to be provided, but the hardware does not have any
+ * such mechanism; the only interrupt masking is at the cpu level and
+ * it affects all interrupts. We provide dummy mask/unmask. The hardware
+ * handles all interrupt control and clears pending status when the cpu
+ * accepts the interrupt.
+ */
+ jcore_aic.irq_mask = noop;
+ jcore_aic.irq_unmask = noop;
+ jcore_aic.name = "AIC";
+
+ domain = irq_domain_add_linear(node, dom_sz, &jcore_aic_irqdomain_ops,
+ &jcore_aic);
+ if (!domain)
+ return -ENOMEM;
+ irq_create_strict_mappings(domain, min_irq, min_irq, dom_sz - min_irq);
+
+ return 0;
+}
+
+IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
+IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);
--
1.8.1.rc1
>From b4df2503d1e0d7ab5d487504df2354f1b23bfe4d Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias at libc.org>
Date: Thu, 17 Mar 2016 23:12:57 +0000
Subject: [PATCH] clocksource: add J-Core timer/clocksource driver
At the hardware level, the J-Core PIT is integrated with the interrupt
controller, but it is represented as its own device and has an
independent programming interface. It provides a 12-bit countdown
timer, which is not presently used, and a periodic timer. The interval
length for the latter is programmable via a 32-bit throttle register
whose units are determined by a bus-period register. The periodic
timer is used to implement both periodic and oneshot clock event
modes; in oneshot mode the interrupt handler simply disables the timer
as soon as it fires.
Despite its device tree node representing an interrupt for the PIT,
the actual irq generated is programmable, not hard-wired. The driver
is responsible for programming the PIT to generate the hardware irq
number that the DT assigns to it.
On SMP configurations, J-Core provides cpu-local instances of the PIT;
no broadcast timer is needed. This driver supports the creation of the
necessary per-cpu clock_event_device instances. The code has been
tested and works on SMP, but will not be usable without additional
J-Core SMP-support patches and appropriate hardware capable of running
SMP.
A nanosecond-resolution clocksource is provided using the J-Core "RTC"
registers, which give a 64-bit seconds count and 32-bit nanoseconds.
The driver converts these to a 64-bit nanoseconds count.
Signed-off-by: Rich Felker <dalias at libc.org>
---
drivers/clocksource/Kconfig | 9 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/jcore-pit.c | 242 ++++++++++++++++++++++++++++++++++++++++
include/linux/cpuhotplug.h | 1 +
4 files changed, 253 insertions(+)
create mode 100644 drivers/clocksource/jcore-pit.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 5677886..3210ca5 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -407,6 +407,15 @@ config SYS_SUPPORTS_SH_TMU
config SYS_SUPPORTS_EM_STI
bool
+config CLKSRC_JCORE_PIT
+ bool "J-Core PIT timer driver"
+ depends on OF && (SUPERH || COMPILE_TEST)
+ depends on GENERIC_CLOCKEVENTS
+ depends on HAS_IOMEM
+ help
+ This enables build of clocksource and clockevent driver for
+ the integrated PIT in the J-Core synthesizable, open source SoC.
+
config SH_TIMER_CMT
bool "Renesas CMT timer driver" if COMPILE_TEST
depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index fd9d6df..cf87f40 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ATMEL_TCB_CLKSRC) += tcb_clksrc.o
obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o
obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o
obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC) += cs5535-clockevt.o
+obj-$(CONFIG_CLKSRC_JCORE_PIT) += jcore-pit.o
obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o
obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o
obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
diff --git a/drivers/clocksource/jcore-pit.c b/drivers/clocksource/jcore-pit.c
new file mode 100644
index 0000000..23dee50
--- /dev/null
+++ b/drivers/clocksource/jcore-pit.c
@@ -0,0 +1,242 @@
+/*
+ * J-Core SoC PIT/clocksource driver
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define PIT_IRQ_SHIFT 12
+#define PIT_PRIO_SHIFT 20
+#define PIT_ENABLE_SHIFT 26
+#define PIT_IRQ_MASK 0x3f
+#define PIT_PRIO_MASK 0xf
+
+#define REG_PITEN 0x00
+#define REG_THROT 0x10
+#define REG_COUNT 0x14
+#define REG_BUSPD 0x18
+#define REG_SECHI 0x20
+#define REG_SECLO 0x24
+#define REG_NSEC 0x28
+
+struct jcore_pit {
+ struct clock_event_device ced;
+ __iomem void *base;
+ unsigned long periodic_delta;
+ unsigned cpu;
+ u32 enable_val;
+};
+
+static __iomem void *jcore_pit_base;
+static struct clocksource jcore_cs;
+struct jcore_pit __percpu *jcore_pit_percpu;
+
+static notrace u64 jcore_sched_clock_read(void)
+{
+ u32 seclo, nsec, seclo0;
+ __iomem void *base = jcore_pit_base;
+
+ seclo = __raw_readl(base + REG_SECLO);
+ do {
+ seclo0 = seclo;
+ nsec = __raw_readl(base + REG_NSEC);
+ seclo = __raw_readl(base + REG_SECLO);
+ } while (seclo0 != seclo);
+
+ return seclo * NSEC_PER_SEC + nsec;
+}
+
+static cycle_t jcore_clocksource_read(struct clocksource *cs)
+{
+ return jcore_sched_clock_read();
+}
+
+static int jcore_pit_disable(struct jcore_pit *pit)
+{
+ __raw_writel(0, pit->base + REG_PITEN);
+ return 0;
+}
+
+static int jcore_pit_set(unsigned long delta, struct jcore_pit *pit)
+{
+ jcore_pit_disable(pit);
+ __raw_writel(delta, pit->base + REG_THROT);
+ __raw_writel(pit->enable_val, pit->base + REG_PITEN);
+ return 0;
+}
+
+static int jcore_pit_set_state_shutdown(struct clock_event_device *ced)
+{
+ struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+ return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_oneshot(struct clock_event_device *ced)
+{
+ struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+ return jcore_pit_disable(pit);
+}
+
+static int jcore_pit_set_state_periodic(struct clock_event_device *ced)
+{
+ struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+ return jcore_pit_set(pit->periodic_delta, pit);
+}
+
+static int jcore_pit_set_next_event(unsigned long delta,
+ struct clock_event_device *ced)
+{
+ struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);
+
+ return jcore_pit_set(delta, pit);
+}
+
+static int jcore_pit_local_init(unsigned cpu)
+{
+ struct jcore_pit *pit = this_cpu_ptr(jcore_pit_percpu);
+ unsigned buspd, freq;
+
+ pr_info("Local J-Core PIT init on cpu %u\n", pit->cpu);
+
+ buspd = __raw_readl(pit->base + REG_BUSPD);
+ freq = DIV_ROUND_CLOSEST(NSEC_PER_SEC, buspd);
+ pit->periodic_delta = DIV_ROUND_CLOSEST(NSEC_PER_SEC, HZ*buspd);
+
+ clockevents_config_and_register(&pit->ced, freq, 1, ULONG_MAX);
+
+ return 0;
+}
+
+static int jcore_pit_local_shutdown(unsigned cpu)
+{
+ return 0;
+}
+
+static irqreturn_t jcore_timer_interrupt(int irq, void *dev_id)
+{
+ struct jcore_pit *pit = this_cpu_ptr(dev_id);
+
+ if (clockevent_state_oneshot(&pit->ced))
+ jcore_pit_disable(pit);
+
+ pit->ced.event_handler(&pit->ced);
+
+ return IRQ_HANDLED;
+}
+
+static int __init jcore_pit_init(struct device_node *node)
+{
+ int err;
+ unsigned pit_irq, cpu;
+ unsigned long hwirq;
+ u32 irqprio, enable_val;
+
+ jcore_pit_base = of_iomap(node, 0);
+ if (!jcore_pit_base) {
+ pr_err("Error: Cannot map base address for J-Core PIT\n");
+ return -ENXIO;
+ }
+
+ pit_irq = irq_of_parse_and_map(node, 0);
+ if (!pit_irq) {
+ pr_err("Error: J-Core PIT has no IRQ\n");
+ return -ENXIO;
+ }
+
+ pr_info("Initializing J-Core PIT at %p IRQ %d\n",
+ jcore_pit_base, pit_irq);
+
+ jcore_cs.name = "jcore_pit_cs";
+ jcore_cs.rating = 400;
+ jcore_cs.read = jcore_clocksource_read;
+ jcore_cs.mult = 1;
+ jcore_cs.shift = 0;
+ jcore_cs.mask = CLOCKSOURCE_MASK(32);
+ jcore_cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+ err = clocksource_register_hz(&jcore_cs, NSEC_PER_SEC);
+ if (err) {
+ pr_err("Error registering clocksource device: %d\n", err);
+ return err;
+ }
+
+ sched_clock_register(jcore_sched_clock_read, 32, NSEC_PER_SEC);
+
+ jcore_pit_percpu = alloc_percpu(struct jcore_pit);
+ if (!jcore_pit_percpu) {
+ pr_err("Failed to allocate memory for clock event device\n");
+ return -ENOMEM;
+ }
+
+ err = request_irq(pit_irq, jcore_timer_interrupt,
+ IRQF_TIMER | IRQF_PERCPU,
+ "jcore_pit", jcore_pit_percpu);
+ if (err) {
+ pr_err("pit irq request failed: %d\n", err);
+ return err;
+ }
+
+ /*
+ * The J-Core PIT is not hard-wired to a particular IRQ, but
+ * integrated with the interrupt controller such that the IRQ it
+ * generates is programmable. The programming interface has a
+ * legacy field which was an interrupt priority for AIC1, but
+ * which is OR'd onto bits 2-5 of the generated IRQ number when
+ * used with J-Core AIC2, so set it to match these bits.
+ */
+ hwirq = irq_get_irq_data(pit_irq)->hwirq;
+ irqprio = (hwirq >> 2) & PIT_PRIO_MASK;
+ enable_val = (1U << PIT_ENABLE_SHIFT)
+ | (hwirq << PIT_IRQ_SHIFT)
+ | (irqprio << PIT_PRIO_SHIFT);
+
+ for_each_present_cpu(cpu) {
+ struct jcore_pit *pit = per_cpu_ptr(jcore_pit_percpu, cpu);
+
+ pit->base = of_iomap(node, cpu);
+ if (!pit->base) {
+ pr_err("Unable to map PIT for cpu %u\n", cpu);
+ continue;
+ }
+
+ pit->ced.name = "jcore_pit";
+ pit->ced.features = CLOCK_EVT_FEAT_PERIODIC
+ | CLOCK_EVT_FEAT_ONESHOT
+ | CLOCK_EVT_FEAT_PERCPU;
+ pit->ced.cpumask = cpumask_of(cpu);
+ pit->ced.rating = 400;
+ pit->ced.irq = pit_irq;
+ pit->ced.set_state_shutdown = jcore_pit_set_state_shutdown;
+ pit->ced.set_state_periodic = jcore_pit_set_state_periodic;
+ pit->ced.set_state_oneshot = jcore_pit_set_state_oneshot;
+ pit->ced.set_next_event = jcore_pit_set_next_event;
+
+ pit->cpu = cpu;
+ pit->enable_val = enable_val;
+ }
+
+ cpuhp_setup_state(CPUHP_AP_JCORE_TIMER_STARTING,
+ "AP_JCORE_TIMER_STARTING",
+ jcore_pit_local_init, jcore_pit_local_shutdown);
+
+ return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(jcore_pit, "jcore,pit", jcore_pit_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 242bf53..e95ed7d 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -50,6 +50,7 @@ enum cpuhp_state {
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
CPUHP_AP_DUMMY_TIMER_STARTING,
+ CPUHP_AP_JCORE_TIMER_STARTING,
CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
CPUHP_AP_ARM_TWD_STARTING,
CPUHP_AP_METAG_TIMER_STARTING,
--
1.8.1.rc1
>From 1ef5d95d600b4a877725416b2af9454367a97c32 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias at libc.org>
Date: Sun, 3 Apr 2016 05:12:45 +0000
Subject: [PATCH] spi: add driver for J-Core SPI controller
The J-Core "spi2" device is a PIO-based SPI master controller. It
differs from "bitbang" devices in that that it's clocked in hardware
rather than via soft clock modulation over gpio, and performs
byte-at-a-time transfers between the cpu and SPI controller.
This driver will be extended to support future versions of the J-Core
SPI controller with DMA transfers when they become available.
Signed-off-by: Rich Felker <dalias at libc.org>
---
drivers/spi/Kconfig | 7 ++
drivers/spi/Makefile | 1 +
drivers/spi/spi-jcore.c | 232 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 240 insertions(+)
create mode 100644 drivers/spi/spi-jcore.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index d6fb8d4..1abb3d7 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -285,6 +285,13 @@ config SPI_IMX
This enables using the Freescale i.MX SPI controllers in master
mode.
+config SPI_JCORE
+ tristate "J-Core SPI Master"
+ depends on OF && (SUPERH || COMPILE_TEST)
+ help
+ This enables support for the SPI master controller in the J-Core
+ synthesizable, open source SoC.
+
config SPI_LM70_LLP
tristate "Parallel port adapter for LM70 eval board (DEVELOPMENT)"
depends on PARPORT
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 185367e..8715fec 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_SPI_FSL_SPI) += spi-fsl-spi.o
obj-$(CONFIG_SPI_GPIO) += spi-gpio.o
obj-$(CONFIG_SPI_IMG_SPFI) += spi-img-spfi.o
obj-$(CONFIG_SPI_IMX) += spi-imx.o
+obj-$(CONFIG_SPI_JCORE) += spi-jcore.o
obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o
obj-$(CONFIG_SPI_LP8841_RTC) += spi-lp8841-rtc.o
obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o
diff --git a/drivers/spi/spi-jcore.c b/drivers/spi/spi-jcore.c
new file mode 100644
index 0000000..7d2044a
--- /dev/null
+++ b/drivers/spi/spi-jcore.c
@@ -0,0 +1,232 @@
+/*
+ * J-Core SPI controller driver
+ *
+ * Copyright (C) 2012-2016 Smart Energy Instruments, Inc.
+ *
+ * Current version by Rich Felker
+ * Based loosely on initial version by Oleksandr G Zhadan
+ *
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+
+#define DRV_NAME "jcore_spi"
+
+#define CTRL_REG 0x0
+#define DATA_REG 0x4
+
+#define JCORE_SPI_CTRL_XMIT 0x02
+#define JCORE_SPI_STAT_BUSY 0x02
+#define JCORE_SPI_CTRL_LOOP 0x08
+#define JCORE_SPI_CTRL_CS_BITS 0x15
+
+#define JCORE_SPI_WAIT_RDY_MAX_LOOP 2000000
+
+struct jcore_spi {
+ struct spi_master *master;
+ void __iomem *base;
+ unsigned int cs_reg;
+ unsigned int speed_reg;
+ unsigned int speed_hz;
+ unsigned int clock_freq;
+};
+
+static int jcore_spi_wait(void __iomem *ctrl_reg)
+{
+ unsigned timeout = JCORE_SPI_WAIT_RDY_MAX_LOOP;
+
+ do {
+ if (!(readl(ctrl_reg) & JCORE_SPI_STAT_BUSY))
+ return 0;
+ cpu_relax();
+ } while (--timeout);
+
+ return -EBUSY;
+}
+
+static void jcore_spi_program(struct jcore_spi *hw)
+{
+ void __iomem *ctrl_reg = hw->base + CTRL_REG;
+
+ if (jcore_spi_wait(ctrl_reg))
+ dev_err(hw->master->dev.parent,
+ "timeout waiting to program ctrl reg.\n");
+
+ writel(hw->cs_reg | hw->speed_reg, ctrl_reg);
+}
+
+static void jcore_spi_chipsel(struct spi_device *spi, bool value)
+{
+ struct jcore_spi *hw = spi_master_get_devdata(spi->master);
+ u32 csbit = 1U << (2 * spi->chip_select);
+
+ dev_dbg(hw->master->dev.parent, "chipselect %d\n", spi->chip_select);
+
+ if (value)
+ hw->cs_reg |= csbit;
+ else
+ hw->cs_reg &= ~csbit;
+
+ jcore_spi_program(hw);
+}
+
+static void jcore_spi_baudrate(struct jcore_spi *hw, int speed)
+{
+ if (speed == hw->speed_hz) return;
+ hw->speed_hz = speed;
+ if (speed >= hw->clock_freq / 2)
+ hw->speed_reg = 0;
+ else
+ hw->speed_reg = ((hw->clock_freq / 2 / speed) - 1) << 27;
+ jcore_spi_program(hw);
+ dev_dbg(hw->master->dev.parent, "speed=%d reg=0x%x\n",
+ speed, hw->speed_reg);
+}
+
+static int jcore_spi_txrx(struct spi_master *master, struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct jcore_spi *hw = spi_master_get_devdata(master);
+
+ void __iomem *ctrl_reg = hw->base + CTRL_REG;
+ void __iomem *data_reg = hw->base + DATA_REG;
+ u32 xmit;
+
+ /* data buffers */
+ const unsigned char *tx;
+ unsigned char *rx;
+ unsigned int len;
+ unsigned int count;
+
+ jcore_spi_baudrate(hw, t->speed_hz);
+
+ xmit = hw->cs_reg | hw->speed_reg | JCORE_SPI_CTRL_XMIT;
+ tx = t->tx_buf;
+ rx = t->rx_buf;
+ len = t->len;
+
+ for (count = 0; count < len; count++) {
+ if (jcore_spi_wait(ctrl_reg))
+ break;
+
+ writel(tx ? *tx++ : 0, data_reg);
+ writel(xmit, ctrl_reg);
+
+ if (jcore_spi_wait(ctrl_reg))
+ break;
+
+ if (rx)
+ *rx++ = readl(data_reg);
+ }
+
+ spi_finalize_current_transfer(master);
+
+ if (count < len)
+ return -EREMOTEIO;
+
+ return 0;
+}
+
+static int jcore_spi_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct jcore_spi *hw;
+ struct spi_master *master;
+ struct resource *res;
+ u32 clock_freq;
+ struct clk *clk;
+ int err = -ENODEV;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct jcore_spi));
+ if (!master)
+ return err;
+
+ /* Setup the master state. */
+ master->num_chipselect = 3;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+ master->transfer_one = jcore_spi_txrx;
+ master->set_cs = jcore_spi_chipsel;
+ master->dev.of_node = node;
+ master->bus_num = pdev->id;
+
+ hw = spi_master_get_devdata(master);
+ hw->master = master;
+ platform_set_drvdata(pdev, hw);
+
+ /* Find and map our resources */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ goto exit_busy;
+ if (!devm_request_mem_region(&pdev->dev, res->start,
+ resource_size(res), pdev->name))
+ goto exit_busy;
+ hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
+ resource_size(res));
+ if (!hw->base)
+ goto exit_busy;
+
+ /*
+ * The SPI clock rate controlled via a configurable clock divider
+ * which is applied to the reference clock. A 50 MHz reference is
+ * most suitable for obtaining standard SPI clock rates, but some
+ * designs may have a different reference clock, and the DT must
+ * make the driver aware so that it can properly program the
+ * requested rate. If the clock is omitted, 50 MHz is assumed.
+ */
+ clock_freq = 50000000;
+ clk = devm_clk_get(&pdev->dev, "ref_clk");
+ if (!IS_ERR_OR_NULL(clk)) {
+ if (clk_enable(clk) == 0)
+ clock_freq = clk_get_rate(clk);
+ else
+ dev_warn(&pdev->dev, "could not enable ref_clk\n");
+ }
+ hw->clock_freq = clock_freq;
+
+ /* Initialize all CS bits to high. */
+ hw->cs_reg = JCORE_SPI_CTRL_CS_BITS;
+ jcore_spi_baudrate(hw, 400000);
+
+ /* Register our spi controller */
+ err = devm_spi_register_master(&pdev->dev, master);
+ if (err)
+ goto exit;
+
+ return 0;
+
+exit_busy:
+ err = -EBUSY;
+exit:
+ platform_set_drvdata(pdev, NULL);
+ spi_master_put(master);
+ return err;
+}
+
+static const struct of_device_id jcore_spi_of_match[] = {
+ { .compatible = "jcore,spi2" },
+ {},
+};
+
+static struct platform_driver jcore_spi_driver = {
+ .probe = jcore_spi_probe,
+ .driver = {
+ .name = DRV_NAME,
+ .of_match_table = jcore_spi_of_match,
+ },
+};
+
+module_platform_driver(jcore_spi_driver);
+
+MODULE_DESCRIPTION("J-Core SPI driver");
+MODULE_AUTHOR("Rich Felker <dalias at libc.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
--
1.8.1.rc1
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