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Message-ID: <YgpZnZ5onP5JYVEH@google.com>
Date: Mon, 14 Feb 2022 13:31:09 +0000
From: Lee Jones <lee.jones@...aro.org>
To: Claudiu Beznea <claudiu.beznea@...rochip.com>
Cc: arnd@...db.de, linux-kernel@...r.kernel.org
Subject: Re: [RESEND][PATCH] mfd: syscon: allow mapping a range of addresses
Arnd,
> Allow the mapping of a range of addresses for syscon. This is done through
> regmap_config::wr_table, regmap_config::rd_table. Previously, only one
> range could have been allocated to a syscon via
> regmap_config::max_register. The code is needed for SAMA7G5 whose reset
> controller contains a register (at offset 0xE001D0E4, see below) that is
> used to control the USB PHYs but that register is not located continuously
> in reset controller address space, as follows:
Would you be kind enough to look at this please?
> Controller's name Memory space Offset
> ... ... ...
> +------------+ 0xE001D000
> Reset controller | |
> +------------+ 0xE001D010
> Shutdown controller | |
> +------------+ 0xE001D020
> RTT controller | |
> +------------+ 0xE001D050
> ... ... ...
> +------------+ 0xE001D0E4
> Reset controller | |
> +------------+ 0xE001D0E8
> ... ... ...
>
> To control the PHYs the proper syscon is retrieved from proper driver.
> With previous approach only the first range passed though device tree
> was taken into account by syscon. With the code in this patch the
> following DT bindings:
>
> reset_controller: rstc@...1d000 {
> compatible = "microchip,sama7g5-rstc",
> "microchip,sam9x60-rstc", "syscon";
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0xe001d000 0x8>,
> <0xe001d0e4 0x4>;
> clocks = <&clk32k 0>;
> };
>
> Are translated into a syscon regmap with:
> - allowed ranges: [0x0, 0xC) u [0xE4, 0xE8)
> - invalid ranges: [0xC, 0xE0]
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
> ---
> drivers/mfd/syscon.c | 158 +++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 143 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index 191fdb87c424..fe80e6150d95 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -20,9 +20,36 @@
> #include <linux/platform_data/syscon.h>
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> +#include <linux/types.h>
> #include <linux/mfd/syscon.h>
> #include <linux/slab.h>
>
> +#define syscon_alloc(_dev, args...) ({ \
> + void *_ptr; \
> + if (_dev) \
> + _ptr = devm_kzalloc((_dev), args); \
> + else \
> + _ptr = kzalloc(args); \
> + (_ptr); \
> +})
> +
> +#define syscon_get_resource(_pdev, _np, _idx, _res) ({ \
> + int _ret = -EINVAL; \
> + if (_pdev) { \
> + struct resource *_r; \
> + _r = platform_get_resource((_pdev), IORESOURCE_MEM, (_idx));\
> + if (!_r) { \
> + _ret = -ENOMEM; \
> + } else { \
> + (_res) = *_r; \
> + _ret = 0; \
> + } \
> + } else if (_np) { \
> + _ret = of_address_to_resource((_np), (_idx), &(_res)); \
> + } \
> + (_ret); \
> +})
> +
> static struct platform_driver syscon_driver;
>
> static DEFINE_SPINLOCK(syscon_list_slock);
> @@ -40,14 +67,93 @@ static const struct regmap_config syscon_regmap_config = {
> .reg_stride = 4,
> };
>
> +static const struct regmap_access_table *
> +syscon_prepare_regmap_access_table(struct platform_device *pdev,
> + struct device_node *np, u32 reg_io_width,
> + int entries)
> +{
> + struct regmap_access_table *at;
> + struct regmap_range *yes_ranges, *no_ranges = NULL;
> + struct device *dev = pdev ? &pdev->dev : NULL;
> + struct resource res;
> + resource_size_t base_offset, offset;
> + int i, ret;
> +
> + /* Allocate memory for access table. */
> + at = syscon_alloc(dev, sizeof(*at), GFP_KERNEL);
> + if (!at)
> + return ERR_PTR(-ENOMEM);
> +
> + /* Allocate memory for allowed ranges. */
> + yes_ranges = syscon_alloc(dev, entries * sizeof(*yes_ranges),
> + GFP_KERNEL);
> + if (!yes_ranges) {
> + ret = -ENOMEM;
> + goto free;
> + }
> +
> + /* Allocate memory for invalid ranges. */
> + if (entries > 1) {
> + no_ranges = syscon_alloc(dev,
> + (entries - 1) * sizeof(*no_ranges),
> + GFP_KERNEL);
> + if (!no_ranges) {
> + ret = -ENOMEM;
> + goto free;
> + }
> + }
> +
> + /* Populate allowed and invalid ranges. */
> + ret = syscon_get_resource(pdev, np, 0, res);
> + if (ret)
> + goto free;
> +
> + base_offset = res.start;
> + yes_ranges[0].range_max = resource_size(&res) - reg_io_width;
> + if (entries > 1)
> + no_ranges[0].range_min = resource_size(&res);
> +
> + for (i = 1; i < entries; i++) {
> + ret = syscon_get_resource(pdev, np, i, res);
> + if (ret)
> + goto free;
> +
> + offset = res.start - base_offset;
> + yes_ranges[i].range_min = offset;
> + yes_ranges[i].range_max = offset + resource_size(&res) -
> + reg_io_width;
> + if (i != entries - 1)
> + no_ranges[i].range_min = offset + resource_size(&res);
> + no_ranges[i - 1].range_max = offset - reg_io_width;
> + }
> +
> + /* Store them to access table. */
> + at->yes_ranges = yes_ranges;
> + at->n_yes_ranges = entries;
> + at->no_ranges = no_ranges;
> + at->n_no_ranges = entries > 1 ? entries - 1 : 0;
> +
> + return at;
> +
> +free:
> + if (!dev) {
> + kfree(no_ranges);
> + kfree(yes_ranges);
> + kfree(at);
> + }
> +
> + return ERR_PTR(ret);
> +}
> +
> static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> {
> struct clk *clk;
> struct syscon *syscon;
> struct regmap *regmap;
> void __iomem *base;
> + const struct regmap_access_table *at;
> u32 reg_io_width;
> - int ret;
> + int ret, n_res = 0;
> struct regmap_config syscon_config = syscon_regmap_config;
> struct resource res;
>
> @@ -55,11 +161,29 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> if (!syscon)
> return ERR_PTR(-ENOMEM);
>
> - if (of_address_to_resource(np, 0, &res)) {
> + /* Count the number of resources. */
> + while (of_address_to_resource(np, n_res, &res) == 0)
> + n_res++;
> + if (!n_res) {
> ret = -ENOMEM;
> goto err_map;
> }
>
> + /*
> + * search for reg-io-width property in DT. If it is not provided,
> + * default to 4 bytes. regmap_init_mmio will return an error if values
> + * are invalid so there is no need to check them here.
> + */
> + ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
> + if (ret)
> + reg_io_width = 4;
> +
> + at = syscon_prepare_regmap_access_table(NULL, np, reg_io_width, n_res);
> + if (IS_ERR(at)) {
> + ret = PTR_ERR(at);
> + goto err_map;
> + }
> +
> base = of_iomap(np, 0);
> if (!base) {
> ret = -ENOMEM;
> @@ -74,15 +198,6 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> else if (of_property_read_bool(np, "native-endian"))
> syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
>
> - /*
> - * search for reg-io-width property in DT. If it is not provided,
> - * default to 4 bytes. regmap_init_mmio will return an error if values
> - * are invalid so there is no need to check them here.
> - */
> - ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
> - if (ret)
> - reg_io_width = 4;
> -
> ret = of_hwspin_lock_get_id(np, 0);
> if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
> syscon_config.use_hwlock = true;
> @@ -105,7 +220,8 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> (u64)res.start);
> syscon_config.reg_stride = reg_io_width;
> syscon_config.val_bits = reg_io_width * 8;
> - syscon_config.max_register = resource_size(&res) - reg_io_width;
> + syscon_config.wr_table = at;
> + syscon_config.rd_table = at;
>
> regmap = regmap_init_mmio(NULL, base, &syscon_config);
> kfree(syscon_config.name);
> @@ -147,6 +263,9 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> iounmap(base);
> err_map:
> kfree(syscon);
> + kfree(at->no_ranges);
> + kfree(at->yes_ranges);
> + kfree(at);
> return ERR_PTR(ret);
> }
>
> @@ -279,22 +398,31 @@ static int syscon_probe(struct platform_device *pdev)
> struct syscon_platform_data *pdata = dev_get_platdata(dev);
> struct syscon *syscon;
> struct regmap_config syscon_config = syscon_regmap_config;
> + const struct regmap_access_table *at;
> struct resource *res;
> void __iomem *base;
> + int n_res = 0;
>
> syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
> if (!syscon)
> return -ENOMEM;
>
> - res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - if (!res)
> + /* Count the number of resources. */
> + while (platform_get_resource(pdev, IORESOURCE_MEM, n_res))
> + n_res++;
> + if (!n_res)
> return -ENOENT;
>
> base = devm_ioremap(dev, res->start, resource_size(res));
> if (!base)
> return -ENOMEM;
>
> - syscon_config.max_register = resource_size(res) - 4;
> + at = syscon_prepare_regmap_access_table(pdev, NULL, 4, n_res);
> + if (IS_ERR(at))
> + return PTR_ERR(at);
> +
> + syscon_config.wr_table = at;
> + syscon_config.rd_table = at;
> if (pdata)
> syscon_config.name = pdata->label;
> syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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