Hi Aneesh,
On 2/4/2012 1:16 PM, Aneesh V wrote:
> EMIF is an SDRAM controller used in various Texas Instruments
> SoCs. EMIF supports, based on its revision, one or more of
> LPDDR2/DDR2/DDR3 protocols.
>
> Add the basic infrastructure for EMIF driver that includes
> driver registration, probe, parsing of platform data etc.
>
> Signed-off-by: Aneesh V<aneesh@xxxxxx>
> ---
> drivers/misc/Kconfig | 12 ++
> drivers/misc/Makefile | 1 +
> drivers/misc/emif.c | 300 +++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/emif.h | 160 ++++++++++++++++++++++++++
> 4 files changed, 473 insertions(+), 0 deletions(-)
> create mode 100644 drivers/misc/emif.c
> create mode 100644 include/linux/emif.h
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 8337bf6..d68184a 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -459,6 +459,18 @@ config DDR
> information. This data is useful for drivers handling
> DDR SDRAM controllers.
>
> +config EMIF
> + tristate "Texas Instruments EMIF driver"
> + select DDR
> + help
> + This driver is for the EMIF module available in Texas Instruments
> + SoCs. EMIF is an SDRAM controller that, based on its revision,
> + supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols.
> + This driver takes care of only LPDDR2 memories presently. The
> + functions of the driver includes re-configuring AC timing
> + parameters and other settings during frequency, voltage and
> + temperature changes
> +
> config ARM_CHARLCD
> bool "ARM Ltd. Character LCD Driver"
> depends on PLAT_VERSATILE
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 4759166..076db0f 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_C2PORT) += c2port/
> obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/
> obj-$(CONFIG_HMC6352) += hmc6352.o
> obj-$(CONFIG_DDR) += jedec_ddr_data.o
> +obj-$(CONFIG_EMIF) += emif.o
> obj-y += eeprom/
> obj-y += cb710/
> obj-$(CONFIG_SPEAR13XX_PCIE_GADGET) += spear13xx_pcie_gadget.o
> diff --git a/drivers/misc/emif.c b/drivers/misc/emif.c
> new file mode 100644
> index 0000000..ba1e3f9
> --- /dev/null
> +++ b/drivers/misc/emif.c
> @@ -0,0 +1,300 @@
> +/*
> + * EMIF driver
> + *
> + * Copyright (C) 2010 Texas Instruments, Inc.
Nit: 2012?
> + *
> + * Aneesh V<aneesh@xxxxxx>
> + * Santosh Shilimkar<santosh.shilimkar@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include<linux/kernel.h>
> +#include<linux/reboot.h>
> +#include<linux/emif.h>
> +#include<linux/io.h>
> +#include<linux/device.h>
> +#include<linux/platform_device.h>
> +#include<linux/interrupt.h>
> +#include<linux/slab.h>
> +#include<linux/seq_file.h>
> +#include<linux/module.h>
> +#include<linux/spinlock.h>
> +#include "emif_regs.h"
> +
> +/**
> + * struct emif_data - Per device static data for driver's use
> + * @duplicate: Whether the DDR devices attached to this EMIF
> + * instance are exactly same as that on EMIF1. In
> + * this case we can save some memory and processing
> + * @temperature_level: Maximum temperature of LPDDR2 devices attached
> + * to this EMIF - read from MR4 register. If there
> + * are two devices attached to this EMIF, this
> + * value is the maximum of the two temperature
> + * levels.
> + * @irq: IRQ number
Do you really need to store the IRQ number?
> + * @lock: lock for protecting temperature_level and
> + * associated actions from race conditions
> + * @base: base address of memory-mapped IO registers.
> + * @dev: device pointer.
> + * @addressing table with addressing information from the spec
> + * @regs_cache: An array of 'struct emif_regs' that stores
> + * calculated register values for different
> + * frequencies, to avoid re-calculating them on
> + * each DVFS transition.
> + * @curr_regs: The set of register values used in the last
> + * frequency change (i.e. corresponding to the
> + * frequency in effect at the moment)
> + * @plat_data: Pointer to saved platform data.
> + */
> +struct emif_data {
> + u8 duplicate;
> + u8 temperature_level;
> + u32 irq;
> + spinlock_t lock; /* lock to prevent races */
Nit: That comment is useless, since you already have the kerneldoc comment before.
> + void __iomem *base;
> + struct device *dev;
> + const struct lpddr2_addressing *addressing;
> + struct emif_regs *regs_cache[EMIF_MAX_NUM_FREQUENCIES];
> + struct emif_regs *curr_regs;
> + struct emif_platform_data *plat_data;
> +};
> +
> +static struct emif_data *emif1;
> +
> +static void __exit cleanup_emif(struct emif_data *emif)
> +{
> + if (emif) {
> + if (emif->plat_data) {
> + kfree(emif->plat_data->custom_configs);
> + kfree(emif->plat_data->timings);
> + kfree(emif->plat_data->min_tck);
> + kfree(emif->plat_data->device_info);
> + kfree(emif->plat_data);
> + }
> + kfree(emif);
> + }
> +}
> +
> +static void get_default_timings(struct emif_data *emif)
> +{
> + struct emif_platform_data *pd = emif->plat_data;
> +
> + pd->timings = lpddr2_jedec_timings;
> + pd->timings_arr_size = ARRAY_SIZE(lpddr2_jedec_timings);
> +
> + dev_warn(emif->dev, "Using default timings\n");
> +}
> +
> +static int is_dev_data_valid(u32 type, u32 density, u32 io_width, u32 phy_type,
> + u32 ip_rev, struct device *dev)
> +{
> + int valid;
> +
> + valid = (type == DDR_TYPE_LPDDR2_S4 ||
> + type == DDR_TYPE_LPDDR2_S2)
> + && (density>= DDR_DENSITY_64Mb
> + && density<= DDR_DENSITY_8Gb)
> + && (io_width>= DDR_IO_WIDTH_8
> + && io_width<= DDR_IO_WIDTH_32);
> +
> + /* Combinations of EMIF and PHY revisions that we support today */
> + switch (ip_rev) {
> + case EMIF_4D:
> + valid = valid&& (phy_type == EMIF_PHY_TYPE_ATTILAPHY);
> + break;
> + case EMIF_4D5:
> + valid = valid&& (phy_type == EMIF_PHY_TYPE_INTELLIPHY);
> + break;
> + default:
> + valid = 0;
> + }
> +
> + if (!valid)
> + dev_err(dev, "Invalid DDR details\n");
> + return valid;
> +}
> +
> +static int is_custom_config_valid(struct emif_custom_configs *cust_cfgs,
> + struct device *dev)
> +{
> + int valid = 1;
> +
> + if ((cust_cfgs->mask& EMIF_CUSTOM_CONFIG_LPMODE)&&
> + (cust_cfgs->lpmode != EMIF_LP_MODE_DISABLE))
> + valid = cust_cfgs->lpmode_freq_threshold&&
> + cust_cfgs->lpmode_timeout_performance&&
> + cust_cfgs->lpmode_timeout_power;
> +
> + if (cust_cfgs->mask& EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL)
> + valid = valid&& cust_cfgs->temp_alert_poll_interval_ms;
> +
> + if (!valid)
> + dev_warn(dev, "Invalid custom configs\n");
> +
> + return valid;
> +}
> +
> +static struct emif_data * __init get_device_details(
> + struct platform_device *pdev)
> +{
> + u32 size;
> + struct emif_data *emif = NULL;
> + struct ddr_device_info *dev_info;
> + struct emif_platform_data *pd;
> +
> + pd = pdev->dev.platform_data;
> +
> + if (!(pd&& pd->device_info&& is_dev_data_valid(pd->device_info->type,
> + pd->device_info->density, pd->device_info->io_width,
> + pd->phy_type, pd->ip_rev,&pdev->dev)))
> + goto error;
> +
> + emif = kzalloc(sizeof(struct emif_data), GFP_KERNEL);
You should use the devm_* version of this API to get the simplify the error handling / removal.
> + pd = kmemdup(pd, sizeof(*pd), GFP_KERNEL);
> + dev_info = kmemdup(pd->device_info,
> + sizeof(*pd->device_info), GFP_KERNEL);
> +
> + if (!emif || !pd || !dev_info)
> + goto error;
The error report will not be really useful since you will not return the exact source of failure.
> +
> + emif->plat_data = pd;
> + emif->dev =&pdev->dev;
> + emif->temperature_level = SDRAM_TEMP_NOMINAL;
> +
> + pd->device_info = dev_info;
> +
> + /*
> + * For EMIF instances other than EMIF1 see if the devices connected
> + * are exactly same as on EMIF1(which is typically the case). If so,
> + * mark it as a duplicate of EMIF1 and skip copying timings data.
> + * This will save some memory and some computation later.
> + */
> + emif->duplicate = emif1&& (memcmp(dev_info,
> + emif1->plat_data->device_info,
> + sizeof(struct ddr_device_info)) == 0);
> +
> + if (emif->duplicate) {
> + pd->timings = NULL;
> + pd->min_tck = NULL;
> + goto out;
> + }
> +
> + /*
> + * Copy custom configs - ignore allocation error, if any, as
> + * custom_configs is not very critical
> + */
> + if (pd->custom_configs)
> + pd->custom_configs = kmemdup(pd->custom_configs,
> + sizeof(*pd->custom_configs), GFP_KERNEL);
> +
> + if (pd->custom_configs&&
> + !is_custom_config_valid(pd->custom_configs, emif->dev)) {
> + kfree(pd->custom_configs);
> + pd->custom_configs = NULL;
> + }
> +
> + /*
> + * Copy timings and min-tck values from platform data. If it is not
> + * available or if memory allocation fails, use JEDEC defaults
> + */
> + size = sizeof(struct lpddr2_timings) * pd->timings_arr_size;
> + if (pd->timings)
> + pd->timings = kmemdup(pd->timings, size, GFP_KERNEL);
> +
> + if (!pd->timings)
> + get_default_timings(emif);
> +
> + if (pd->min_tck)
> + pd->min_tck = kmemdup(pd->min_tck, sizeof(*pd->min_tck),
> + GFP_KERNEL);
> +
> + if (!pd->min_tck) {
> + pd->min_tck =&lpddr2_min_tck;
> + dev_warn(emif->dev, "Using default min-tck values\n");
> + }
> +
> + goto out;
> +
> +error:
> + dev_err(&pdev->dev, "get_device_details() failure!!\n");
That's not a very good error message, isn't?
> + cleanup_emif(emif);
> + return NULL;
> +
> +out:
> + return emif;
> +}
> +
> +static int __init emif_probe(struct platform_device *pdev)
> +{
> + struct emif_data *emif;
> + struct resource *res;
> +
> + emif = get_device_details(pdev);
> +
> + if (!emif)
> + goto error;
> +
> + if (!emif1)
> + emif1 = emif;
> +
> + /* Save pointers to each other in emif and device structures */
> + emif->dev =&pdev->dev;
> + platform_set_drvdata(pdev, emif);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + goto error;
You should reserve the region before ioremapping it. Something like that:
if (!devm_request_mem_region(dev, res->start, resource_size(res), pdev->name)) {
dev_err(dev, "Region already claimed\n");
return -EBUSY;
}
> +
> + emif->base = ioremap(res->start, SZ_1M);
Use devm_ioremap.
> + if (!emif->base)
> + goto error;
> +
> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
You should use platform_get_irq instead.
> + if (!res)
> + goto error;
> + emif->irq = res->start;
> +
> + dev_info(&pdev->dev, "Device configured with addr = %p and IRQ%d\n",
> + emif->base, emif->irq);
> + return 0;
> +
> +error:
> + dev_err(&pdev->dev, "probe failure!!\n");
Because??? You should be a little bit more verbose in case of failure.
Regards,
Benoit
> + cleanup_emif(emif);
> + return -ENODEV;
> +}
> +
> +static int __exit emif_remove(struct platform_device *pdev)
> +{
> + struct emif_data *emif = platform_get_drvdata(pdev);
> +
> + cleanup_emif(emif);
> +
> + return 0;
> +}
> +
> +static struct platform_driver emif_driver = {
> + .remove = __exit_p(emif_remove),
> + .driver = {
> + .name = "emif",
> + },
> +};
> +
> +static int __init emif_register(void)
> +{
> + return platform_driver_probe(&emif_driver, emif_probe);
> +}
> +
> +static void __exit emif_unregister(void)
> +{
> + platform_driver_unregister(&emif_driver);
> +}
> +
> +module_init(emif_register);
> +module_exit(emif_unregister);
> +MODULE_DESCRIPTION("TI EMIF SDRAM Controller Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:emif");
> +MODULE_AUTHOR("Texas Instruments Inc");
> diff --git a/include/linux/emif.h b/include/linux/emif.h
> new file mode 100644
> index 0000000..4ddf20b
> --- /dev/null
> +++ b/include/linux/emif.h
> @@ -0,0 +1,160 @@
> +/*
> + * Definitions for EMIF SDRAM controller in TI SoCs
> + *
> + * Copyright (C) 2010 Texas Instruments, Inc.
> + *
> + * Aneesh V<aneesh@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#ifndef __LINUX_EMIF_H
> +#define __LINUX_EMIF_H
> +
> +#ifndef __ASSEMBLY__
> +#include<linux/jedec_ddr.h>
> +
> +/*
> + * Maximum number of different frequencies supported by EMIF driver
> + * Determines the number of entries in the pointer array for register
> + * cache
> + */
> +#define EMIF_MAX_NUM_FREQUENCIES 6
> +
> +/* EMIF_PWR_MGMT_CTRL register */
> +/* Low power modes */
> +#define EMIF_LP_MODE_DISABLE 0
> +#define EMIF_LP_MODE_CLOCK_STOP 1
> +#define EMIF_LP_MODE_SELF_REFRESH 2
> +#define EMIF_LP_MODE_PWR_DN 4
> +
> +/* Hardware capabilities */
> +#define EMIF_HW_CAPS_LL_INTERFACE 0x00000001
> +
> +/* EMIF IP Revisions */
> +#define EMIF_4D 1
> +#define EMIF_4D5 2
> +
> +/* PHY types */
> +#define EMIF_PHY_TYPE_ATTILAPHY 1
> +#define EMIF_PHY_TYPE_INTELLIPHY 2
> +
> +/* Custom config requests */
> +#define EMIF_CUSTOM_CONFIG_LPMODE 0x00000001
> +#define EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL 0x00000002
> +
> +/*
> + * Structure containing shadow of important registers in EMIF
> + * The calculation function fills in this structure to be later used for
> + * initialisation and DVFS
> + */
> +struct emif_regs {
> + u32 freq;
> + u32 ref_ctrl_shdw;
> + u32 ref_ctrl_shdw_derated;
> + u32 sdram_tim1_shdw;
> + u32 sdram_tim1_shdw_derated;
> + u32 sdram_tim2_shdw;
> + u32 sdram_tim3_shdw;
> + u32 sdram_tim3_shdw_derated;
> + u32 pwr_mgmt_ctrl_shdw;
> + union {
> + u32 read_idle_ctrl_shdw_normal;
> + u32 dll_calib_ctrl_shdw_normal;
> + };
> + union {
> + u32 read_idle_ctrl_shdw_volt_ramp;
> + u32 dll_calib_ctrl_shdw_volt_ramp;
> + };
> +
> + u32 phy_ctrl_1_shdw;
> + u32 ext_phy_ctrl_2_shdw;
> + u32 ext_phy_ctrl_3_shdw;
> + u32 ext_phy_ctrl_4_shdw;
> +};
> +
> +/**
> + * struct ddr_device_info - All information about the DDR device except AC
> + * timing parameters
> + * @type: Device type (LPDDR2-S4, LPDDR2-S2 etc)
> + * @density: Device density
> + * @io_width: Bus width
> + * @cs1_used: Whether there is a DDR device attached to the second
> + * chip-select(CS1) of this EMIF instance
> + * @cal_resistors_per_cs: Whether there is one calibration resistor per
> + * chip-select or whether it's a single one for both
> + * @manufacturer: Manufacturer name string
> + */
> +struct ddr_device_info {
> + u32 type;
> + u32 density;
> + u32 io_width;
> + u32 cs1_used;
> + u32 cal_resistors_per_cs;
> + char manufacturer[10];
> +};
> +
> +/**
> + * struct emif_custom_configs - Custom configuration parameters/policies
> + * passed from the platform layer
> + * @mask: Mask to indicate which configs are requested
> + * @lpmode: LPMODE to be used in PWR_MGMT_CTRL register
> + * @lpmode_timeout_performance: Timeout before LPMODE entry when higher
> + * performance is desired at the cost of power (typically
> + * at higher OPPs)
> + * @lpmode_timeout_power: Timeout before LPMODE entry when better power
> + * savings is desired and performance is not important
> + * (typically at lower loads indicated by lower OPPs)
> + * @lpmode_freq_threshold: The DDR frequency threshold to identify between
> + * the above two cases:
> + * timeout = (freq>= lpmode_freq_threshold) ?
> + * lpmode_timeout_performance :
> + * lpmode_timeout_power;
> + * @temp_alert_poll_interval_ms: LPDDR2 MR4 polling interval at nominal
> + * temperature(in milliseconds). When temperature is high
> + * polling is done 4 times as frequently.
> + */
> +struct emif_custom_configs {
> + u32 mask;
> + u32 lpmode;
> + u32 lpmode_timeout_performance;
> + u32 lpmode_timeout_power;
> + u32 lpmode_freq_threshold;
> + u32 temp_alert_poll_interval_ms;
> +};
> +
> +/**
> + * struct emif_platform_data - Platform data passed on EMIF platform
> + * device creation. Used by the driver.
> + * @hw_caps: Hw capabilities of the EMIF IP in the respective SoC
> + * @device_info: Device info structure containing information such
> + * as type, bus width, density etc
> + * @timings: Timings information from device datasheet passed
> + * as an array of 'struct lpddr2_timings'. Can be NULL
> + * if if default timings are ok
> + * @timings_arr_size: Size of the timings array. Depends on the number
> + * of different frequencies for which timings data
> + * is provided
> + * @min_tck: Minimum value of some timing parameters in terms
> + * of number of cycles. Can be NULL if default values
> + * are ok
> + * @custom_configs: Custom configurations requested by SoC or board
> + * code and the data for them. Can be NULL if default
> + * configurations done by the driver are ok. See
> + * documentation for 'struct emif_custom_configs' for
> + * more details
> + */
> +struct emif_platform_data {
> + u32 hw_caps;
> + struct ddr_device_info *device_info;
> + const struct lpddr2_timings *timings;
> + u32 timings_arr_size;
> + const struct lpddr2_min_tck *min_tck;
> + struct emif_custom_configs *custom_configs;
> + u32 ip_rev;
> + u32 phy_type;
> +};
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* __LINUX_EMIF_H */
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