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SubjectRe: [PATCH 3/6] At91: dt: Added smc bus driver
On 31/12/2013 17:32, jjhiblot@traphandler.com wrote:
> From: jean-jacques hiblot <jean-jacques.hiblot@jdsu.com>
>
> The EBI/SMC external interface is used to access external peripherals (NAND
> and Ethernet controller in the case of sam9261ek). Different configurations and
> timings are required for those peripherals. This bus driver can be used to
> setup the bus timings/configuration from the device tree.
>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> ---
> drivers/bus/Kconfig | 9 +++
> drivers/bus/Makefile | 1 +
> drivers/bus/atmel-smc.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++


IMHO this driver should be placed in drivers/memory: the mvebu-devbus
driver provides the same kind of functionnalities.

BTW, I recently had a talk with Nicolas regarding this SMC/EBI driver
and he was about to repost an old patch providing this driver:
http://www.spinics.net/lists/arm-kernel/msg144838.html

I'll take a closer look at your code later ;).

> 3 files changed, 192 insertions(+)
> create mode 100644 drivers/bus/atmel-smc.c
>
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index 552373c..8c944db5 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -12,6 +12,15 @@ config IMX_WEIM
> The WEIM(Wireless External Interface Module) works like a bus.
> You can attach many different devices on it, such as NOR, onenand.
>
> +config ATMEL_SMC
> + bool "Atmel SMC/EBI driver"
> + depends on SOC_AT91SAM9 && OF
> + help
> + Driver for Atmel SMC/EBI controller.
> + Used to configure the EBI (external bus interface) when the device-
> + tree is used. This bus supports NANDs, external ethernet controller,
> + SRAMs, ATA devices.
> +
> config MVEBU_MBUS
> bool
> depends on PLAT_ORION
> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
> index 8947bdd..4364003 100644
> --- a/drivers/bus/Makefile
> +++ b/drivers/bus/Makefile
> @@ -2,6 +2,7 @@
> # Makefile for the bus drivers.
> #
>
> +obj-$(CONFIG_ATMEL_SMC) += atmel-smc.o
> obj-$(CONFIG_IMX_WEIM) += imx-weim.o
> obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
> obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o
> diff --git a/drivers/bus/atmel-smc.c b/drivers/bus/atmel-smc.c
> new file mode 100644
> index 0000000..06e530d
> --- /dev/null
> +++ b/drivers/bus/atmel-smc.c
> @@ -0,0 +1,182 @@
> +/*
> + * EBI driver for Atmel SAM9 chips
> + * inspired by the fsl weim bus driver
> + *
> + * Copyright (C) 2013 JJ Hiblot.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +#include <linux/module.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/of_device.h>
> +#include <mach/at91sam9_smc.h>
> +
> +struct at91_smc_devtype {
> + unsigned int cs_count;
> +};
> +
> +static const struct at91_smc_devtype sam9261_smc_devtype = {
> + .cs_count = 6,
> +};
> +
> +static const struct of_device_id smc_id_table[] = {
> + { .compatible = "atmel,at91sam9261-smc", .data = &sam9261_smc_devtype},
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, smc_id_table);
> +
> +struct smc_parameters_type {
> + const char *name;
> + u16 reg;
> + u16 width;
> + u16 shift;
> +};
> +
> +#define SETUP 0
> +#define PULSE 1
> +#define CYCLE 2
> +#define MODE 3
> +static const struct smc_parameters_type smc_parameters[] = {
> + {"smc,ncs_read_setup", SETUP, 6, 24},
> + {"smc,nrd_setup", SETUP, 6, 16},
> + {"smc,ncs_write_setup", SETUP, 6, 8},
> + {"smc,nwe_setup", SETUP, 6, 0},
> + {"smc,ncs_read_pulse", PULSE, 6, 24},
> + {"smc,nrd_pulse", PULSE, 6, 16},
> + {"smc,ncs_write_pulse", PULSE, 6, 8},
> + {"smc,nwe_pulse", PULSE, 6, 0},
> + {"smc,read_cycle", CYCLE, 9, 16},
> + {"smc,write_cycle", CYCLE, 9, 0},
> + {"smc,burst_size", MODE, 2, 28},
> + {"smc,burst_enabled", MODE, 1, 24},
> + {"smc,tdf_mode", MODE, 1, 20},
> + {"smc,tdf_cycles", MODE, 4, 16},
> + {"smc,bus_width", MODE, 2, 12},
> + {"smc,byte_access_type", MODE, 1, 8},
> + {"smc,nwait_mode", MODE, 2, 4},
> + {"smc,write_mode", MODE, 1, 0},
> + {"smc,read_mode", MODE, 1, 1},
> + {NULL}
> +};
> +
> +/* Parse and set the timing for this device. */
> +static int __init smc_timing_setup(struct device *dev, struct device_node *np,
> + void __iomem *base, const struct at91_smc_devtype *devtype)
> +{
> + u32 val;
> + int ret;
> + u32 cs;
> + const struct smc_parameters_type *p = smc_parameters;
> + u32 shadow_smc_regs[5];
> +
> + ret = of_property_read_u32(np, "smc,cs" , &cs);
> + if (ret < 0) {
> + dev_err(dev, "missing mandatory property : smc,cs\n");
> + return ret;
> + }
> + if (val >= devtype->cs_count) {
> + dev_err(dev, "invalid value for property smc,cs (=%d)."
> + "Must be in range 0 to %d\n", cs, devtype->cs_count-1);
> + return -EINVAL;
> + }
> +
> + /* set the timing for EBI */
> + base += (0x10 * cs);
> + shadow_smc_regs[SETUP] = readl_relaxed(base + AT91_SMC_SETUP);
> + shadow_smc_regs[PULSE] = readl_relaxed(base + AT91_SMC_PULSE);
> + shadow_smc_regs[CYCLE] = readl_relaxed(base + AT91_SMC_CYCLE);
> + shadow_smc_regs[MODE] = readl_relaxed(base + AT91_SMC_MODE);
> +
> + while (p->name) {
> + ret = of_property_read_u32(np, p->name , &val);
> + if (ret == -EINVAL) {
> + dev_dbg(dev, "cs %d: property %s not set.\n", cs,
> + p->name);
> + p++;
> + continue;
> + } else if (ret) {
> + dev_err(dev, "cs %d: can't get property %s.\n", cs,
> + p->name);
> + return ret;
> + }
> + if (val >= (1<<p->width)) {
> + dev_err(dev, "cs %d: property %s out of range.\n", cs,
> + p->name);
> + return -ERANGE;
> + }
> + shadow_smc_regs[p->reg] &= ~(((1<<p->width)-1) << p->shift);
> + shadow_smc_regs[p->reg] |= (val << p->shift);
> + p++;
> + }
> + writel_relaxed(shadow_smc_regs[SETUP], base + AT91_SMC_SETUP);
> + writel_relaxed(shadow_smc_regs[PULSE], base + AT91_SMC_PULSE);
> + writel_relaxed(shadow_smc_regs[CYCLE], base + AT91_SMC_CYCLE);
> + writel_relaxed(shadow_smc_regs[MODE], base + AT91_SMC_MODE);
> + return 0;
> +}
> +
> +static int __init smc_parse_dt(struct platform_device *pdev,
> + void __iomem *base)
> +{
> + struct device *dev = &pdev->dev;
> + const struct of_device_id *of_id = of_match_device(smc_id_table, dev);
> + const struct at91_smc_devtype *devtype = of_id->data;
> + struct device_node *child;
> + int ret;
> +
> + for_each_child_of_node(dev->of_node, child) {
> + if (!child->name)
> + continue;
> +
> + ret = smc_timing_setup(dev, child, base, devtype);
> + if (ret) {
> + dev_err(dev, "%s set timing failed.\n",
> + child->full_name);
> + return ret;
> + }
> + }
> +
> + ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
> + if (ret)
> + dev_err(dev, "%s fail to create devices.\n",
> + dev->of_node->full_name);
> + return ret;
> +}
> +
> +static int __init smc_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + void __iomem *base;
> + int ret;
> +
> + /* get the resource */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + base = devm_request_and_ioremap(&pdev->dev, res);
> + if (IS_ERR(base)) {
> + dev_err(&pdev->dev, "can't map SMC base address\n");
> + return PTR_ERR(base);
> + }
> +
> + /* parse the device node */
> + ret = smc_parse_dt(pdev, base);
> + if (!ret)
> + dev_info(&pdev->dev, "Driver registered.\n");
> +
> + return ret;
> +}
> +
> +static struct platform_driver smc_driver = {
> + .driver = {
> + .name = "atmel-smc",
> + .owner = THIS_MODULE,
> + .of_match_table = smc_id_table,
> + },
> +};
> +module_platform_driver_probe(smc_driver, smc_probe);
> +
> +MODULE_AUTHOR("JJ Hiblot");
> +MODULE_DESCRIPTION("Atmel's SMC/EBI driver");
> +MODULE_LICENSE("GPL");
>



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