Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755475AbaAIRAD (ORCPT ); Thu, 9 Jan 2014 12:00:03 -0500 Received: from 15.mo3.mail-out.ovh.net ([87.98.150.177]:38864 "EHLO mo3.mail-out.ovh.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751705AbaAIQ74 (ORCPT ); Thu, 9 Jan 2014 11:59:56 -0500 Message-ID: <52CED586.7030602@overkiz.com> Date: Thu, 09 Jan 2014 17:59:50 +0100 From: boris brezillon User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Jean-Jacques Hiblot , nicolas.ferre@atmel.com, arnd@arndb.de CC: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 07/12] at91: dt: smc: Added smc bus driver References: <1389270709-32662-1-git-send-email-jjhiblot@traphandler.com> <1389270709-32662-8-git-send-email-jjhiblot@traphandler.com> In-Reply-To: <1389270709-32662-8-git-send-email-jjhiblot@traphandler.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 15396118277076908121 X-Ovh-Remote: 80.245.18.66 () X-Ovh-Local: 213.186.33.20 (ns0.ovh.net) X-OVH-SPAMSTATE: OK X-OVH-SPAMSCORE: -100 X-OVH-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeejtddrfeduucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd X-Spam-Check: DONE|U 0.5/N X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeejtddrfedtucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello JJ, On 09/01/2014 13:31, Jean-Jacques Hiblot wrote: > 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. > It currently accepts timings in clock period and in nanoseconds. > > Signed-off-by: Jean-Jacques Hiblot > --- > drivers/memory/Kconfig | 10 ++ > drivers/memory/Makefile | 1 + > drivers/memory/atmel-smc.c | 431 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 442 insertions(+) > create mode 100644 drivers/memory/atmel-smc.c > > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig > index 29a11db..fbdfd63 100644 > --- a/drivers/memory/Kconfig > +++ b/drivers/memory/Kconfig > @@ -50,4 +50,14 @@ config TEGRA30_MC > analysis, especially for IOMMU/SMMU(System Memory Management > Unit) module. > > +config ATMEL_SMC > + bool "Atmel SMC/EBI driver" > + default y > + 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, etc. > + > endif > diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile > index 969d923..101abc4 100644 > --- a/drivers/memory/Makefile > +++ b/drivers/memory/Makefile > @@ -9,3 +9,4 @@ obj-$(CONFIG_TI_EMIF) += emif.o > obj-$(CONFIG_MVEBU_DEVBUS) += mvebu-devbus.o > obj-$(CONFIG_TEGRA20_MC) += tegra20-mc.o > obj-$(CONFIG_TEGRA30_MC) += tegra30-mc.o > +obj-$(CONFIG_ATMEL_SMC) += atmel-smc.o > diff --git a/drivers/memory/atmel-smc.c b/drivers/memory/atmel-smc.c > new file mode 100644 > index 0000000..0a1d9ba > --- /dev/null > +++ b/drivers/memory/atmel-smc.c > @@ -0,0 +1,431 @@ > +/* > + * 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 > +#include > +#include > +#include > +#include You should avoid machine specific headers inclusions: we're trying to get rid of them. Duplicate the code and macros you need in your driver instead. > + > +struct smc_data { > + struct clk *bus_clk; > + void __iomem *base; > + struct device *dev; > +}; > + > +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 width; > + u16 shift; > +}; > + > +static const struct smc_parameters_type smc_parameters[] = { > + {"smc,burst_size", 2, 28}, > + {"smc,burst_enabled", 1, 24}, > + {"smc,tdf_mode", 1, 20}, > + {"smc,bus_width", 2, 12}, > + {"smc,byte_access_type", 1, 8}, > + {"smc,nwait_mode", 2, 4}, > + {"smc,write_mode", 1, 0}, > + {"smc,read_mode", 1, 1}, > + {NULL} > +}; > + > +static int get_mode_register_from_dt(struct smc_data *smc, > + struct device_node *np, > + struct sam9_smc_config *cfg) > +{ > + int ret; > + u32 val; > + struct device *dev = smc->dev; > + const struct smc_parameters_type *p = smc_parameters; > + u32 mode = cfg->mode; > + > + while (p->name) { > + ret = of_property_read_u32(np, p->name , &val); > + if (ret == -EINVAL) { > + dev_dbg(dev, "%s: property %s not set.\n", np->name, > + p->name); > + p++; > + continue; > + } else if (ret) { > + dev_err(dev, "%s: can't get property %s.\n", np->name, > + p->name); > + return ret; > + } > + if (val >= (1<width)) { > + dev_err(dev, "%s: property %s out of range.\n", > + np->name, p->name); > + return -ERANGE; > + } > + mode &= ~(((1<width)-1) << p->shift); > + mode |= (val << p->shift); > + p++; > + } > + cfg->mode = mode; > + return 0; > +} > + > +static int generic_timing_from_dt(struct smc_data *smc, struct device_node *np, > + struct sam9_smc_config *cfg) > +{ > + u32 val; > + > + if (!of_property_read_u32(np, "smc,ncs_read_setup" , &val)) > + cfg->ncs_read_setup = val; > + > + if (!of_property_read_u32(np, "smc,nrd_setup" , &val)) > + cfg->nrd_setup = val; > + > + if (!of_property_read_u32(np, "smc,ncs_write_setup" , &val)) > + cfg->ncs_write_setup = val; > + > + if (!of_property_read_u32(np, "smc,nwe_setup" , &val)) > + cfg->nwe_setup = val; > + > + if (!of_property_read_u32(np, "smc,ncs_read_pulse" , &val)) > + cfg->ncs_read_pulse = val; > + > + if (!of_property_read_u32(np, "smc,nrd_pulse" , &val)) > + cfg->nrd_pulse = val; > + > + if (!of_property_read_u32(np, "smc,ncs_write_pulse" , &val)) > + cfg->ncs_write_pulse = val; > + > + if (!of_property_read_u32(np, "smc,nwe_pulse" , &val)) > + cfg->nwe_pulse = val; > + > + if (!of_property_read_u32(np, "smc,read_cycle" , &val)) > + cfg->read_cycle = val; > + > + if (!of_property_read_u32(np, "smc,write_cycle" , &val)) > + cfg->write_cycle = val; > + > + if (!of_property_read_u32(np, "smc,tdf_cycles" , &val)) > + cfg->tdf_cycles = val; > + > + return get_mode_register_from_dt(smc, np, cfg); > +} > + > +/* convert the time in ns in a number of clock cycles */ > +static u32 ns_to_cycles(u32 ns, u32 clk) > +{ > + /* > + * convert the clk to kHz for the rest of the calculation to avoid > + * overflow > + */ > + u32 clk_kHz = clk / 1000; > + u32 ncycles = ((ns * clk_kHz) + 1000000 - 1) / 1000000; What about using an u64 type and do_div ? > + return ncycles; > +} > + > +static u32 cycles_to_coded_cycle(u32 cycles, int a, int b) > +{ > + u32 mask_high = (1 << a) - 1; > + u32 mask_low = (1 << b) - 1; > + u32 coded; > + > + /* check if the value can be described with the coded format */ > + if (cycles & (mask_high & ~mask_low)) { > + /* not representable. we need to round up */ > + cycles |= mask_high; > + cycles += 1; > + } > + /* Now the value can be represented in the coded format */ > + coded = (cycles & ~mask_high) >> (a - b); > + coded |= (cycles & mask_low); > + return coded; > +} > + > +static u32 ns_to_rw_cycles(u32 ns, u32 clk) > +{ > + return cycles_to_coded_cycle(ns_to_cycles(ns, clk), 8, 7); > +} > + > +static u32 ns_to_pulse_cycles(u32 ns, u32 clk) > +{ > + return cycles_to_coded_cycle(ns_to_cycles(ns, clk), 8, 6); > +} > + > +static u32 ns_to_setup_cycles(u32 ns, u32 clk) > +{ > + return cycles_to_coded_cycle(ns_to_cycles(ns, clk), 7, 5); > +} > + > +static u32 cycles_to_ns(u32 cycles, u32 clk) > +{ > + /* > + * convert the clk to kHz for the rest of the calculation to avoid > + * overflow > + */ > + u32 clk_kHz = clk / 1000; Ditto (u64 + do_div). > + return (cycles * 1000000) / clk_kHz; > +} > + > +static u32 coded_cycle_to_cycles(u32 coded, int a, int b) > +{ > + u32 cycles = (coded >> b) << a; > + u32 mask_low = (1 << b) - 1; > + cycles |= (coded & mask_low); > + return cycles; > +} > + > +static u32 rw_cycles_to_ns(u32 reg, u32 clk) > +{ > + return cycles_to_ns(coded_cycle_to_cycles(reg, 8, 7), clk); > +} > + > +static u32 pulse_cycles_to_ns(u32 reg, u32 clk) > +{ > + return cycles_to_ns(coded_cycle_to_cycles(reg, 8, 6), clk); > +} > + > +static u32 setup_cycles_to_ns(u32 reg, u32 clk) > +{ > + return cycles_to_ns(coded_cycle_to_cycles(reg, 7, 5), clk); > +} > + > +static void dump_timing(struct smc_data *smc, struct sam9_smc_config *config) > +{ > + u32 freq = clk_get_rate(smc->bus_clk); > + struct device *dev = smc->dev; > + > +#define DUMP(fn, y) dev_info(dev, "%s : 0x%x (%d ns)\n", #y, config->y,\ > + fn(config->y, freq)) > +#define DUMP_PULSE(y) DUMP(pulse_cycles_to_ns, y) > +#define DUMP_RWCYCLE(y) DUMP(rw_cycles_to_ns, y) > +#define DUMP_SETUP(y) DUMP(setup_cycles_to_ns, y) > +#define DUMP_SIMPLE(y) DUMP(cycles_to_ns, y) > + > + DUMP_SETUP(nwe_setup); > + DUMP_SETUP(ncs_write_setup); > + DUMP_SETUP(nrd_setup); > + DUMP_SETUP(ncs_read_setup); > + DUMP_PULSE(nwe_pulse); > + DUMP_PULSE(ncs_write_pulse); > + DUMP_PULSE(nrd_pulse); > + DUMP_PULSE(ncs_read_pulse); > + DUMP_RWCYCLE(write_cycle); > + DUMP_RWCYCLE(read_cycle); > + DUMP_SIMPLE(tdf_cycles); > +} > + > +static int ns_timing_from_dt(struct smc_data *smc, struct device_node *np, > + struct sam9_smc_config *cfg) > +{ > + u32 t_ns; > + u32 freq = clk_get_rate(smc->bus_clk); > + > + if (!of_property_read_u32(np, "smc,ncs_read_setup" , &t_ns)) > + cfg->ncs_read_setup = ns_to_setup_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,nrd_setup" , &t_ns)) > + cfg->nrd_setup = ns_to_setup_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,ncs_write_setup" , &t_ns)) > + cfg->ncs_write_setup = ns_to_setup_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,nwe_setup" , &t_ns)) > + cfg->nwe_setup = ns_to_setup_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,ncs_read_pulse" , &t_ns)) > + cfg->ncs_read_pulse = ns_to_pulse_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,nrd_pulse" , &t_ns)) > + cfg->nrd_pulse = ns_to_pulse_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,ncs_write_pulse" , &t_ns)) > + cfg->ncs_write_pulse = ns_to_pulse_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,nwe_pulse" , &t_ns)) > + cfg->nwe_pulse = ns_to_pulse_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,read_cycle" , &t_ns)) > + cfg->read_cycle = ns_to_rw_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,write_cycle" , &t_ns)) > + cfg->write_cycle = ns_to_rw_cycles(t_ns, freq); > + > + if (!of_property_read_u32(np, "smc,tdf_cycles" , &t_ns)) > + cfg->tdf_cycles = ns_to_cycles(t_ns, freq); > + > + return get_mode_register_from_dt(smc, np, cfg); > +} > + > +struct converter { > + const char *name; > + int (*fn) (struct smc_data *smc, struct device_node *np, > + struct sam9_smc_config *cfg); > +}; > +static const struct converter converters[] = { > + {"raw", generic_timing_from_dt}, > + {"nanosec", ns_timing_from_dt}, > +}; Could you use more specific names like: "atmel,smc-converter-generic" "atmel,smc-converter-nand" ... IMHO the timing unit should be specified in the property names: smc,ncs_read_setup-ns smc,ncs_read_setup-cycles > + > +/* Parse and set the timing for this device. */ > +static int smc_timing_setup(struct smc_data *smc, struct device_node *np, > + const struct at91_smc_devtype *devtype) > +{ > + int ret; > + u32 cs; > + int i; > + struct device *dev = smc->dev; > + const struct converter *converter; > + const char *converter_name = NULL; > + struct sam9_smc_config cfg; > + > + ret = of_property_read_u32(np, "smc,cs" , &cs); Shouldn't this be stored in the reg property ? After all, in your DM9000 patch you use "@cs,offset" to identify the node... > + if (ret < 0) { > + dev_err(dev, "missing mandatory property : smc,cs\n"); > + return ret; > + } > + if (cs >= 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; > + } > + > + of_property_read_string(np, "smc,converter", &converter_name); What about using the "compatible" property + struct of_device_id instead of "smc,converter" property + struct converter ? > + if (converter_name) { > + for (i = 0; i < ARRAY_SIZE(converters); i++) > + if (strcmp(converters[i].name, converter_name) == 0) > + converter = &converters[i]; > + if (!converter) { > + dev_info(dev, "unknown converter. aborting\n"); > + return -EINVAL; > + } > + } else { > + dev_dbg(dev, "cs %d: no smc converter provided. using " > + "raw register values\n", cs); > + converter = &converters[0]; > + } > + dev_dbg(dev, "cs %d using converter : %s\n", cs, converter->name); > + sam9_smc_cs_read(smc->base + (0x10 * cs), &cfg); > + converter->fn(smc, np, &cfg); > + ret = sam9_smc_check_cs_configuration(&cfg); > + if (ret < 0) { > + dev_info(dev, "invalid smc configuration for cs %d." > + "clipping values\n", cs); > + sam9_smc_clip_cs_configuration(&cfg); > + dump_timing(smc, &cfg); > + } > +#ifdef DEBUG > + else > + dump_timing(smc, &cfg); > +#endif I'm not a big fan of #ifdef blocks inside the code. You could define a dummy dump_timing function if DEBUG is not defined: #ifdef DEBUG static void dump_timing(struct smc_data *smc, struct sam9_smc_config *config) { /* your implementation */ } #else static inline void dump_timing(struct smc_data *smc, struct sam9_smc_config *config) { } #endif Or just use dev_dbg when printing things in dump_timing. > + > + sam9_smc_cs_configure(smc->base + (0x10 * cs), &cfg); > + return 0; > +} > + > +static int smc_parse_dt(struct smc_data *smc) > +{ > + struct device *dev = smc->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; > + if (!of_device_is_available(child)) > + continue; > + ret = smc_timing_setup(smc, child, devtype); > + if (ret) { > + static struct property status = { > + .name = "status", > + .value = "disabled", > + .length = sizeof("disabled"), > + }; > + dev_err(dev, "%s set timing failed. This node will be disabled.\n", > + child->full_name); > + ret = of_update_property(child, &status); > + if (ret < 0) { > + dev_err(dev, "can't disable %s. aborting probe\n", > + child->full_name); > + break; The concept of disabling the device if timings cannot be met sounds interresting... Let's see what other maintainers say about this :). > + } > + } > + } > + > + ret = of_platform_populate(dev->of_node, of_default_bus_match_table, > + NULL, dev); > + if (ret) > + dev_err(dev, "%s fail to create devices.\n", > + dev->of_node->full_name); > + > + return ret; > +} > + > +static int smc_probe(struct platform_device *pdev) > +{ > + struct resource *res; > + int ret; > + void __iomem *base; > + struct clk *clk; > + struct smc_data *smc = devm_kzalloc(&pdev->dev, sizeof(struct smc_data), > + GFP_KERNEL); > + > + if (!smc) > + return -ENOMEM; > + > + smc->dev = &pdev->dev; > + > + /* 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); > + } > + > + /* get the clock */ > + clk = devm_clk_get(&pdev->dev, "smc"); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); > + > + smc->bus_clk = clk; > + smc->base = base; > + > + /* parse the device node */ > + ret = smc_parse_dt(smc); > + 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"); That's all for now. :) I'll try to test it this week end on a sama5 board. Best Regards, Boris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/