linux/drivers/rpmsg/qcom_glink_rpm.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2016-2017, Linaro Ltd
   4 */
   5
   6#include <linux/idr.h>
   7#include <linux/interrupt.h>
   8#include <linux/io.h>
   9#include <linux/list.h>
  10#include <linux/mfd/syscon.h>
  11#include <linux/module.h>
  12#include <linux/of.h>
  13#include <linux/of_address.h>
  14#include <linux/platform_device.h>
  15#include <linux/regmap.h>
  16#include <linux/rpmsg.h>
  17#include <linux/slab.h>
  18#include <linux/workqueue.h>
  19#include <linux/mailbox_client.h>
  20
  21#include "rpmsg_internal.h"
  22#include "qcom_glink_native.h"
  23
  24#define RPM_TOC_SIZE            256
  25#define RPM_TOC_MAGIC           0x67727430 /* grt0 */
  26#define RPM_TOC_MAX_ENTRIES     ((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
  27                                 sizeof(struct rpm_toc_entry))
  28
  29#define RPM_TX_FIFO_ID          0x61703272 /* ap2r */
  30#define RPM_RX_FIFO_ID          0x72326170 /* r2ap */
  31
  32#define to_rpm_pipe(p) container_of(p, struct glink_rpm_pipe, native)
  33
  34struct rpm_toc_entry {
  35        __le32 id;
  36        __le32 offset;
  37        __le32 size;
  38} __packed;
  39
  40struct rpm_toc {
  41        __le32 magic;
  42        __le32 count;
  43
  44        struct rpm_toc_entry entries[];
  45} __packed;
  46
  47struct glink_rpm_pipe {
  48        struct qcom_glink_pipe native;
  49
  50        void __iomem *tail;
  51        void __iomem *head;
  52
  53        void __iomem *fifo;
  54};
  55
  56static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
  57{
  58        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
  59        unsigned int head;
  60        unsigned int tail;
  61
  62        head = readl(pipe->head);
  63        tail = readl(pipe->tail);
  64
  65        if (head < tail)
  66                return pipe->native.length - tail + head;
  67        else
  68                return head - tail;
  69}
  70
  71static void glink_rpm_rx_peak(struct qcom_glink_pipe *glink_pipe,
  72                              void *data, unsigned int offset, size_t count)
  73{
  74        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
  75        unsigned int tail;
  76        size_t len;
  77
  78        tail = readl(pipe->tail);
  79        tail += offset;
  80        if (tail >= pipe->native.length)
  81                tail -= pipe->native.length;
  82
  83        len = min_t(size_t, count, pipe->native.length - tail);
  84        if (len) {
  85                __ioread32_copy(data, pipe->fifo + tail,
  86                                len / sizeof(u32));
  87        }
  88
  89        if (len != count) {
  90                __ioread32_copy(data + len, pipe->fifo,
  91                                (count - len) / sizeof(u32));
  92        }
  93}
  94
  95static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
  96                                 size_t count)
  97{
  98        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
  99        unsigned int tail;
 100
 101        tail = readl(pipe->tail);
 102
 103        tail += count;
 104        if (tail >= pipe->native.length)
 105                tail -= pipe->native.length;
 106
 107        writel(tail, pipe->tail);
 108}
 109
 110static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
 111{
 112        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 113        unsigned int head;
 114        unsigned int tail;
 115
 116        head = readl(pipe->head);
 117        tail = readl(pipe->tail);
 118
 119        if (tail <= head)
 120                return pipe->native.length - head + tail;
 121        else
 122                return tail - head;
 123}
 124
 125static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
 126                                           unsigned int head,
 127                                           const void *data, size_t count)
 128{
 129        size_t len;
 130
 131        len = min_t(size_t, count, pipe->native.length - head);
 132        if (len) {
 133                __iowrite32_copy(pipe->fifo + head, data,
 134                                 len / sizeof(u32));
 135        }
 136
 137        if (len != count) {
 138                __iowrite32_copy(pipe->fifo, data + len,
 139                                 (count - len) / sizeof(u32));
 140        }
 141
 142        head += count;
 143        if (head >= pipe->native.length)
 144                head -= pipe->native.length;
 145
 146        return head;
 147}
 148
 149static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
 150                               const void *hdr, size_t hlen,
 151                               const void *data, size_t dlen)
 152{
 153        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
 154        size_t tlen = hlen + dlen;
 155        size_t aligned_dlen;
 156        unsigned int head;
 157        char padding[8] = {0};
 158        size_t pad;
 159
 160        /* Header length comes from glink native and is always 4 byte aligned */
 161        if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
 162                return;
 163
 164        /*
 165         * Move the unaligned tail of the message to the padding chunk, to
 166         * ensure word aligned accesses
 167         */
 168        aligned_dlen = ALIGN_DOWN(dlen, 4);
 169        if (aligned_dlen != dlen)
 170                memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
 171
 172        head = readl(pipe->head);
 173        head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
 174        head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
 175
 176        pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
 177        if (pad)
 178                head = glink_rpm_tx_write_one(pipe, head, padding, pad);
 179        writel(head, pipe->head);
 180}
 181
 182static int glink_rpm_parse_toc(struct device *dev,
 183                               void __iomem *msg_ram,
 184                               size_t msg_ram_size,
 185                               struct glink_rpm_pipe *rx,
 186                               struct glink_rpm_pipe *tx)
 187{
 188        struct rpm_toc *toc;
 189        int num_entries;
 190        unsigned int id;
 191        size_t offset;
 192        size_t size;
 193        void *buf;
 194        int i;
 195
 196        buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
 197        if (!buf)
 198                return -ENOMEM;
 199
 200        __ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
 201                        RPM_TOC_SIZE / sizeof(u32));
 202
 203        toc = buf;
 204
 205        if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
 206                dev_err(dev, "RPM TOC has invalid magic\n");
 207                goto err_inval;
 208        }
 209
 210        num_entries = le32_to_cpu(toc->count);
 211        if (num_entries > RPM_TOC_MAX_ENTRIES) {
 212                dev_err(dev, "Invalid number of toc entries\n");
 213                goto err_inval;
 214        }
 215
 216        for (i = 0; i < num_entries; i++) {
 217                id = le32_to_cpu(toc->entries[i].id);
 218                offset = le32_to_cpu(toc->entries[i].offset);
 219                size = le32_to_cpu(toc->entries[i].size);
 220
 221                if (offset > msg_ram_size || offset + size > msg_ram_size) {
 222                        dev_err(dev, "TOC entry with invalid size\n");
 223                        continue;
 224                }
 225
 226                switch (id) {
 227                case RPM_RX_FIFO_ID:
 228                        rx->native.length = size;
 229
 230                        rx->tail = msg_ram + offset;
 231                        rx->head = msg_ram + offset + sizeof(u32);
 232                        rx->fifo = msg_ram + offset + 2 * sizeof(u32);
 233                        break;
 234                case RPM_TX_FIFO_ID:
 235                        tx->native.length = size;
 236
 237                        tx->tail = msg_ram + offset;
 238                        tx->head = msg_ram + offset + sizeof(u32);
 239                        tx->fifo = msg_ram + offset + 2 * sizeof(u32);
 240                        break;
 241                }
 242        }
 243
 244        if (!rx->fifo || !tx->fifo) {
 245                dev_err(dev, "Unable to find rx and tx descriptors\n");
 246                goto err_inval;
 247        }
 248
 249        kfree(buf);
 250        return 0;
 251
 252err_inval:
 253        kfree(buf);
 254        return -EINVAL;
 255}
 256
 257static int glink_rpm_probe(struct platform_device *pdev)
 258{
 259        struct qcom_glink *glink;
 260        struct glink_rpm_pipe *rx_pipe;
 261        struct glink_rpm_pipe *tx_pipe;
 262        struct device_node *np;
 263        void __iomem *msg_ram;
 264        size_t msg_ram_size;
 265        struct device *dev = &pdev->dev;
 266        struct resource r;
 267        int ret;
 268
 269        rx_pipe = devm_kzalloc(&pdev->dev, sizeof(*rx_pipe), GFP_KERNEL);
 270        tx_pipe = devm_kzalloc(&pdev->dev, sizeof(*tx_pipe), GFP_KERNEL);
 271        if (!rx_pipe || !tx_pipe)
 272                return -ENOMEM;
 273
 274        np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
 275        ret = of_address_to_resource(np, 0, &r);
 276        of_node_put(np);
 277        if (ret)
 278                return ret;
 279
 280        msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
 281        msg_ram_size = resource_size(&r);
 282        if (!msg_ram)
 283                return -ENOMEM;
 284
 285        ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
 286                                  rx_pipe, tx_pipe);
 287        if (ret)
 288                return ret;
 289
 290        /* Pipe specific accessors */
 291        rx_pipe->native.avail = glink_rpm_rx_avail;
 292        rx_pipe->native.peak = glink_rpm_rx_peak;
 293        rx_pipe->native.advance = glink_rpm_rx_advance;
 294        tx_pipe->native.avail = glink_rpm_tx_avail;
 295        tx_pipe->native.write = glink_rpm_tx_write;
 296
 297        writel(0, tx_pipe->head);
 298        writel(0, rx_pipe->tail);
 299
 300        glink = qcom_glink_native_probe(&pdev->dev,
 301                                        0,
 302                                        &rx_pipe->native,
 303                                        &tx_pipe->native,
 304                                        true);
 305        if (IS_ERR(glink))
 306                return PTR_ERR(glink);
 307
 308        platform_set_drvdata(pdev, glink);
 309
 310        return 0;
 311}
 312
 313static int glink_rpm_remove(struct platform_device *pdev)
 314{
 315        struct qcom_glink *glink = platform_get_drvdata(pdev);
 316
 317        qcom_glink_native_remove(glink);
 318
 319        return 0;
 320}
 321
 322static const struct of_device_id glink_rpm_of_match[] = {
 323        { .compatible = "qcom,glink-rpm" },
 324        {}
 325};
 326MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
 327
 328static struct platform_driver glink_rpm_driver = {
 329        .probe = glink_rpm_probe,
 330        .remove = glink_rpm_remove,
 331        .driver = {
 332                .name = "qcom_glink_rpm",
 333                .of_match_table = glink_rpm_of_match,
 334        },
 335};
 336
 337static int __init glink_rpm_init(void)
 338{
 339        return platform_driver_register(&glink_rpm_driver);
 340}
 341subsys_initcall(glink_rpm_init);
 342
 343static void __exit glink_rpm_exit(void)
 344{
 345        platform_driver_unregister(&glink_rpm_driver);
 346}
 347module_exit(glink_rpm_exit);
 348
 349MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
 350MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
 351MODULE_LICENSE("GPL v2");
 352