--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel IXP4xx Expansion Bus Controller
+ * Copyright (C) 2021 Linaro Ltd.
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/log2.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IXP4XX_EXP_NUM_CS 8
+
+#define IXP4XX_EXP_TIMING_CS0 0x00
+#define IXP4XX_EXP_TIMING_CS1 0x04
+#define IXP4XX_EXP_TIMING_CS2 0x08
+#define IXP4XX_EXP_TIMING_CS3 0x0c
+#define IXP4XX_EXP_TIMING_CS4 0x10
+#define IXP4XX_EXP_TIMING_CS5 0x14
+#define IXP4XX_EXP_TIMING_CS6 0x18
+#define IXP4XX_EXP_TIMING_CS7 0x1c
+
+/* Bits inside each CS timing register */
+#define IXP4XX_EXP_TIMING_STRIDE 0x04
+#define IXP4XX_EXP_CS_EN BIT(31)
+#define IXP456_EXP_PAR_EN BIT(30) /* Only on IXP45x and IXP46x */
+#define IXP4XX_EXP_T1_MASK GENMASK(28, 27)
+#define IXP4XX_EXP_T1_SHIFT 28
+#define IXP4XX_EXP_T2_MASK GENMASK(27, 26)
+#define IXP4XX_EXP_T2_SHIFT 26
+#define IXP4XX_EXP_T3_MASK GENMASK(25, 22)
+#define IXP4XX_EXP_T3_SHIFT 22
+#define IXP4XX_EXP_T4_MASK GENMASK(21, 20)
+#define IXP4XX_EXP_T4_SHIFT 20
+#define IXP4XX_EXP_T5_MASK GENMASK(19, 16)
+#define IXP4XX_EXP_T5_SHIFT 16
+#define IXP4XX_EXP_CYC_TYPE_MASK GENMASK(15, 14)
+#define IXP4XX_EXP_CYC_TYPE_SHIFT 14
+#define IXP4XX_EXP_SIZE_MASK GENMASK(13, 10)
+#define IXP4XX_EXP_SIZE_SHIFT 10
+#define IXP4XX_EXP_CNFG_0 BIT(9) /* Always zero */
+#define IXP43X_EXP_SYNC_INTEL BIT(8) /* Only on IXP43x */
+#define IXP43X_EXP_EXP_CHIP BIT(7) /* Only on IXP43x */
+#define IXP4XX_EXP_BYTE_RD16 BIT(6)
+#define IXP4XX_EXP_HRDY_POL BIT(5) /* Only on IXP42x */
+#define IXP4XX_EXP_MUX_EN BIT(4)
+#define IXP4XX_EXP_SPLT_EN BIT(3)
+#define IXP4XX_EXP_WORD BIT(2) /* Always zero */
+#define IXP4XX_EXP_WR_EN BIT(1)
+#define IXP4XX_EXP_BYTE_EN BIT(0)
+#define IXP42X_RESERVED (BIT(30)|IXP4XX_EXP_CNFG_0|BIT(8)|BIT(7)|IXP4XX_EXP_WORD)
+#define IXP43X_RESERVED (BIT(30)|IXP4XX_EXP_CNFG_0|BIT(5)|IXP4XX_EXP_WORD)
+
+#define IXP4XX_EXP_CNFG0 0x20
+#define IXP4XX_EXP_CNFG0_MEM_MAP BIT(31)
+#define IXP4XX_EXP_CNFG1 0x24
+
+#define IXP4XX_EXP_BOOT_BASE 0x00000000
+#define IXP4XX_EXP_NORMAL_BASE 0x50000000
+#define IXP4XX_EXP_STRIDE 0x01000000
+
+/* Fuses on the IXP43x */
+#define IXP43X_EXP_UNIT_FUSE_RESET 0x28
+#define IXP43x_EXP_FUSE_SPEED_MASK GENMASK(23, 22)
+
+/* Number of device tree values in "reg" */
+#define IXP4XX_OF_REG_SIZE 3
+
+struct ixp4xx_eb {
+ struct device *dev;
+ struct regmap *rmap;
+ u32 bus_base;
+ bool is_42x;
+ bool is_43x;
+};
+
+struct ixp4xx_exp_tim_prop {
+ const char *prop;
+ u32 max;
+ u32 mask;
+ u16 shift;
+};
+
+static const struct ixp4xx_exp_tim_prop ixp4xx_exp_tim_props[] = {
+ {
+ .prop = "intel,ixp4xx-eb-t1",
+ .max = 3,
+ .mask = IXP4XX_EXP_T1_MASK,
+ .shift = IXP4XX_EXP_T1_SHIFT,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-t2",
+ .max = 3,
+ .mask = IXP4XX_EXP_T2_MASK,
+ .shift = IXP4XX_EXP_T2_SHIFT,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-t3",
+ .max = 15,
+ .mask = IXP4XX_EXP_T3_MASK,
+ .shift = IXP4XX_EXP_T3_SHIFT,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-t4",
+ .max = 3,
+ .mask = IXP4XX_EXP_T4_MASK,
+ .shift = IXP4XX_EXP_T4_SHIFT,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-t5",
+ .max = 15,
+ .mask = IXP4XX_EXP_T5_MASK,
+ .shift = IXP4XX_EXP_T5_SHIFT,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-byte-access-on-halfword",
+ .max = 1,
+ .mask = IXP4XX_EXP_BYTE_RD16,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-hpi-hrdy-pol-high",
+ .max = 1,
+ .mask = IXP4XX_EXP_HRDY_POL,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-mux-address-and-data",
+ .max = 1,
+ .mask = IXP4XX_EXP_MUX_EN,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-ahb-split-transfers",
+ .max = 1,
+ .mask = IXP4XX_EXP_SPLT_EN,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-write-enable",
+ .max = 1,
+ .mask = IXP4XX_EXP_WR_EN,
+ },
+ {
+ .prop = "intel,ixp4xx-eb-byte-access",
+ .max = 1,
+ .mask = IXP4XX_EXP_BYTE_EN,
+ },
+};
+
+static void ixp4xx_exp_setup_chipselect(struct ixp4xx_eb *eb,
+ struct device_node *np,
+ u32 cs_index,
+ u32 cs_size)
+{
+ u32 cs_cfg;
+ u32 val;
+ u32 cur_cssize;
+ u32 cs_order;
+ int ret;
+ int i;
+
+ if (eb->is_42x && (cs_index > 7)) {
+ dev_err(eb->dev,
+ "invalid chipselect %u, we only support 0-7\n",
+ cs_index);
+ return;
+ }
+ if (eb->is_43x && (cs_index > 3)) {
+ dev_err(eb->dev,
+ "invalid chipselect %u, we only support 0-3\n",
+ cs_index);
+ return;
+ }
+
+ /* Several chip selects can be joined into one device */
+ if (cs_size > IXP4XX_EXP_STRIDE)
+ cur_cssize = IXP4XX_EXP_STRIDE;
+ else
+ cur_cssize = cs_size;
+
+
+ /*
+ * The following will read/modify/write the configuration for one
+ * chipselect, attempting to leave the boot defaults in place unless
+ * something is explicitly defined.
+ */
+ regmap_read(eb->rmap, IXP4XX_EXP_TIMING_CS0 +
+ IXP4XX_EXP_TIMING_STRIDE * cs_index, &cs_cfg);
+ dev_info(eb->dev, "CS%d at %#08x, size %#08x, config before: %#08x\n",
+ cs_index, eb->bus_base + IXP4XX_EXP_STRIDE * cs_index,
+ cur_cssize, cs_cfg);
+
+ /* Size set-up first align to 2^9 .. 2^24 */
+ cur_cssize = roundup_pow_of_two(cur_cssize);
+ if (cur_cssize < 512)
+ cur_cssize = 512;
+ cs_order = ilog2(cur_cssize);
+ if (cs_order < 9 || cs_order > 24) {
+ dev_err(eb->dev, "illegal size order %d\n", cs_order);
+ return;
+ }
+ dev_dbg(eb->dev, "CS%d size order: %d\n", cs_index, cs_order);
+ cs_cfg &= ~(IXP4XX_EXP_SIZE_MASK);
+ cs_cfg |= ((cs_order - 9) << IXP4XX_EXP_SIZE_SHIFT);
+
+ for (i = 0; i < ARRAY_SIZE(ixp4xx_exp_tim_props); i++) {
+ const struct ixp4xx_exp_tim_prop *ip = &ixp4xx_exp_tim_props[i];
+
+ /* All are regular u32 values */
+ ret = of_property_read_u32(np, ip->prop, &val);
+ if (ret)
+ continue;
+
+ /* Handle bools (single bits) first */
+ if (ip->max == 1) {
+ if (val)
+ cs_cfg |= ip->mask;
+ else
+ cs_cfg &= ~ip->mask;
+ dev_info(eb->dev, "CS%d %s %s\n", cs_index,
+ val ? "enabled" : "disabled",
+ ip->prop);
+ continue;
+ }
+
+ if (val > ip->max) {
+ dev_err(eb->dev,
+ "CS%d too high value for %s: %u, capped at %u\n",
+ cs_index, ip->prop, val, ip->max);
+ val = ip->max;
+ }
+ /* This assumes max value fills all the assigned bits (and it does) */
+ cs_cfg &= ~ip->mask;
+ cs_cfg |= (val << ip->shift);
+ dev_info(eb->dev, "CS%d set %s to %u\n", cs_index, ip->prop, val);
+ }
+
+ ret = of_property_read_u32(np, "intel,ixp4xx-eb-cycle-type", &val);
+ if (!ret) {
+ if (val > 3) {
+ dev_err(eb->dev, "illegal cycle type %d\n", val);
+ return;
+ }
+ dev_info(eb->dev, "CS%d set cycle type %d\n", cs_index, val);
+ cs_cfg &= ~IXP4XX_EXP_CYC_TYPE_MASK;
+ cs_cfg |= val << IXP4XX_EXP_CYC_TYPE_SHIFT;
+ }
+
+ if (eb->is_42x)
+ cs_cfg &= ~IXP42X_RESERVED;
+ if (eb->is_43x) {
+ cs_cfg &= ~IXP43X_RESERVED;
+ /*
+ * This bit for Intel strata flash is currently unused, but let's
+ * report it if we find one.
+ */
+ if (cs_cfg & IXP43X_EXP_SYNC_INTEL)
+ dev_info(eb->dev, "claims to be Intel strata flash\n");
+ }
+ cs_cfg |= IXP4XX_EXP_CS_EN;
+
+ regmap_write(eb->rmap,
+ IXP4XX_EXP_TIMING_CS0 + IXP4XX_EXP_TIMING_STRIDE * cs_index,
+ cs_cfg);
+ dev_info(eb->dev, "CS%d wrote %#08x into CS config\n", cs_index, cs_cfg);
+
+ /*
+ * If several chip selects are joined together into one big
+ * device area, we call ourselves recursively for each successive
+ * chip select. For a 32MB flash chip this results in two calls
+ * for example.
+ */
+ if (cs_size > IXP4XX_EXP_STRIDE)
+ ixp4xx_exp_setup_chipselect(eb, np,
+ cs_index + 1,
+ cs_size - IXP4XX_EXP_STRIDE);
+}
+
+static void ixp4xx_exp_setup_child(struct ixp4xx_eb *eb,
+ struct device_node *np)
+{
+ u32 cs_sizes[IXP4XX_EXP_NUM_CS];
+ int num_regs;
+ u32 csindex;
+ u32 cssize;
+ int ret;
+ int i;
+
+ num_regs = of_property_count_elems_of_size(np, "reg", IXP4XX_OF_REG_SIZE);
+ if (num_regs <= 0)
+ return;
+ dev_dbg(eb->dev, "child %s has %d register sets\n",
+ of_node_full_name(np), num_regs);
+
+ for (csindex = 0; csindex < IXP4XX_EXP_NUM_CS; csindex++)
+ cs_sizes[csindex] = 0;
+
+ for (i = 0; i < num_regs; i++) {
+ u32 rbase, rsize;
+
+ ret = of_property_read_u32_index(np, "reg",
+ i * IXP4XX_OF_REG_SIZE, &csindex);
+ if (ret)
+ break;
+ ret = of_property_read_u32_index(np, "reg",
+ i * IXP4XX_OF_REG_SIZE + 1, &rbase);
+ if (ret)
+ break;
+ ret = of_property_read_u32_index(np, "reg",
+ i * IXP4XX_OF_REG_SIZE + 2, &rsize);
+ if (ret)
+ break;
+
+ if (csindex >= IXP4XX_EXP_NUM_CS) {
+ dev_err(eb->dev, "illegal CS %d\n", csindex);
+ continue;
+ }
+ /*
+ * The memory window always starts from CS base so we need to add
+ * the start and size to get to the size from the start of the CS
+ * base. For example if CS0 is at 0x50000000 and the reg is
+ * <0 0xe40000 0x40000> the size is e80000.
+ *
+ * Roof this if we have several regs setting the same CS.
+ */
+ cssize = rbase + rsize;
+ dev_dbg(eb->dev, "CS%d size %#08x\n", csindex, cssize);
+ if (cs_sizes[csindex] < cssize)
+ cs_sizes[csindex] = cssize;
+ }
+
+ for (csindex = 0; csindex < IXP4XX_EXP_NUM_CS; csindex++) {
+ cssize = cs_sizes[csindex];
+ if (!cssize)
+ continue;
+ /* Just this one, so set it up and return */
+ ixp4xx_exp_setup_chipselect(eb, np, csindex, cssize);
+ }
+}
+
+static int ixp4xx_exp_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct ixp4xx_eb *eb;
+ struct device_node *child;
+ bool have_children = false;
+ u32 val;
+ int ret;
+
+ eb = devm_kzalloc(dev, sizeof(*eb), GFP_KERNEL);
+ if (!eb)
+ return -ENOMEM;
+
+ eb->dev = dev;
+ eb->is_42x = of_device_is_compatible(np, "intel,ixp42x-expansion-bus-controller");
+ eb->is_43x = of_device_is_compatible(np, "intel,ixp43x-expansion-bus-controller");
+
+ eb->rmap = syscon_node_to_regmap(np);
+ if (IS_ERR(eb->rmap))
+ return dev_err_probe(dev, PTR_ERR(eb->rmap), "no regmap\n");
+
+ /* We check that the regmap work only on first read */
+ ret = regmap_read(eb->rmap, IXP4XX_EXP_CNFG0, &val);
+ if (ret)
+ dev_err_probe(dev, ret, "cannot read regmap\n");
+ if (val & IXP4XX_EXP_CNFG0_MEM_MAP)
+ eb->bus_base = IXP4XX_EXP_BOOT_BASE;
+ else
+ eb->bus_base = IXP4XX_EXP_NORMAL_BASE;
+ dev_info(dev, "expansion bus at %08x\n", eb->bus_base);
+
+ if (eb->is_43x) {
+ /* Check some fuses */
+ regmap_read(eb->rmap, IXP43X_EXP_UNIT_FUSE_RESET, &val);
+ switch (FIELD_GET(IXP43x_EXP_FUSE_SPEED_MASK, val)) {
+ case 0:
+ dev_info(dev, "IXP43x at 533 MHz\n");
+ break;
+ case 1:
+ dev_info(dev, "IXP43x at 400 MHz\n");
+ break;
+ case 2:
+ dev_info(dev, "IXP43x at 667 MHz\n");
+ break;
+ default:
+ dev_info(dev, "IXP43x unknown speed\n");
+ break;
+ }
+ }
+
+ /* Walk over the child nodes and see what chipselects we use */
+ for_each_available_child_of_node(np, child) {
+ ixp4xx_exp_setup_child(eb, child);
+ /* We have at least one child */
+ have_children = true;
+ }
+
+ if (have_children)
+ return of_platform_default_populate(np, NULL, dev);
+
+ return 0;
+}
+
+static const struct of_device_id ixp4xx_exp_of_match[] = {
+ { .compatible = "intel,ixp42x-expansion-bus-controller", },
+ { .compatible = "intel,ixp43x-expansion-bus-controller", },
+ { .compatible = "intel,ixp45x-expansion-bus-controller", },
+ { .compatible = "intel,ixp46x-expansion-bus-controller", },
+ { }
+};
+
+static struct platform_driver ixp4xx_exp_driver = {
+ .probe = ixp4xx_exp_probe,
+ .driver = {
+ .name = "intel-extbus",
+ .of_match_table = ixp4xx_exp_of_match,
+ },
+};
+module_platform_driver(ixp4xx_exp_driver);
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("Intel IXP4xx external bus driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff