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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/mtd/devices/slram.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/mtd/devices/slram.c')
| -rw-r--r-- | drivers/mtd/devices/slram.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/drivers/mtd/devices/slram.c b/drivers/mtd/devices/slram.c new file mode 100644 index 000000000..aa38ecdff --- /dev/null +++ b/drivers/mtd/devices/slram.c @@ -0,0 +1,354 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*====================================================================== + + This driver provides a method to access memory not used by the kernel + itself (i.e. if the kernel commandline mem=xxx is used). To actually + use slram at least mtdblock or mtdchar is required (for block or + character device access). + + Usage: + + if compiled as loadable module: + modprobe slram map=<name>,<start>,<end/offset> + if statically linked into the kernel use the following kernel cmd.line + slram=<name>,<start>,<end/offset> + + <name>: name of the device that will be listed in /proc/mtd + <start>: start of the memory region, decimal or hex (0xabcdef) + <end/offset>: end of the memory region. It's possible to use +0x1234 + to specify the offset instead of the absolute address + + NOTE: + With slram it's only possible to map a contiguous memory region. Therefore + if there's a device mapped somewhere in the region specified slram will + fail to load (see kernel log if modprobe fails). + + - + + Jochen Schaeuble <psionic@psionic.de> + +======================================================================*/ + + +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/ptrace.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/timer.h> +#include <linux/major.h> +#include <linux/fs.h> +#include <linux/ioctl.h> +#include <linux/init.h> +#include <linux/io.h> + +#include <linux/mtd/mtd.h> + +#define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */ +#define SLRAM_BLK_SZ 0x4000 + +#define T(fmt, args...) printk(KERN_DEBUG fmt, ## args) +#define E(fmt, args...) printk(KERN_NOTICE fmt, ## args) + +typedef struct slram_priv { + u_char *start; + u_char *end; +} slram_priv_t; + +typedef struct slram_mtd_list { + struct mtd_info *mtdinfo; + struct slram_mtd_list *next; +} slram_mtd_list_t; + +#ifdef MODULE +static char *map[SLRAM_MAX_DEVICES_PARAMS]; + +module_param_array(map, charp, NULL, 0); +MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\""); +#else +static char *map; +#endif + +static slram_mtd_list_t *slram_mtdlist = NULL; + +static int slram_erase(struct mtd_info *, struct erase_info *); +static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **, + resource_size_t *); +static int slram_unpoint(struct mtd_info *, loff_t, size_t); +static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *); +static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *); + +static int slram_erase(struct mtd_info *mtd, struct erase_info *instr) +{ + slram_priv_t *priv = mtd->priv; + + memset(priv->start + instr->addr, 0xff, instr->len); + + return(0); +} + +static int slram_point(struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, void **virt, resource_size_t *phys) +{ + slram_priv_t *priv = mtd->priv; + + *virt = priv->start + from; + *retlen = len; + return(0); +} + +static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) +{ + return 0; +} + +static int slram_read(struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, u_char *buf) +{ + slram_priv_t *priv = mtd->priv; + + memcpy(buf, priv->start + from, len); + *retlen = len; + return(0); +} + +static int slram_write(struct mtd_info *mtd, loff_t to, size_t len, + size_t *retlen, const u_char *buf) +{ + slram_priv_t *priv = mtd->priv; + + memcpy(priv->start + to, buf, len); + *retlen = len; + return(0); +} + +/*====================================================================*/ + +static int register_device(char *name, unsigned long start, unsigned long length) +{ + slram_mtd_list_t **curmtd; + slram_mtd_list_t *new_mtd; + struct mtd_info *mtdinfo; + slram_priv_t *priv; + int ret = -ENOMEM; + + curmtd = &slram_mtdlist; + while (*curmtd) { + curmtd = &(*curmtd)->next; + } + + new_mtd = kmalloc_obj(slram_mtd_list_t); + if (!new_mtd) { + E("slram: Cannot allocate new MTD device.\n"); + return(-ENOMEM); + } + new_mtd->next = NULL; + + mtdinfo = kzalloc_obj(struct mtd_info); + if (!mtdinfo) { + E("slram: Cannot allocate new MTD device.\n"); + goto err_free_list; + } + new_mtd->mtdinfo = mtdinfo; + + priv = kzalloc_obj(slram_priv_t); + if (!priv) { + E("slram: Cannot allocate new MTD device.\n"); + goto err_free_mtdinfo; + } + mtdinfo->priv = priv; + + priv->start = memremap(start, length, + MEMREMAP_WB | MEMREMAP_WT | MEMREMAP_WC); + if (!priv->start) { + E("slram: memremap failed\n"); + ret = -EIO; + goto err_free_priv; + } + priv->end = priv->start + length; + + mtdinfo->name = name; + mtdinfo->size = length; + mtdinfo->flags = MTD_CAP_RAM; + mtdinfo->_erase = slram_erase; + mtdinfo->_point = slram_point; + mtdinfo->_unpoint = slram_unpoint; + mtdinfo->_read = slram_read; + mtdinfo->_write = slram_write; + mtdinfo->owner = THIS_MODULE; + mtdinfo->type = MTD_RAM; + mtdinfo->erasesize = SLRAM_BLK_SZ; + mtdinfo->writesize = 1; + + if (mtd_device_register(mtdinfo, NULL, 0)) { + E("slram: Failed to register new device\n"); + ret = -EAGAIN; + goto err_unmap; + } + *curmtd = new_mtd; + T("slram: Registered device %s from %luKiB to %luKiB\n", name, + (start / 1024), ((start + length) / 1024)); + T("slram: Mapped from 0x%p to 0x%p\n", priv->start, priv->end); + return 0; + +err_unmap: + memunmap(priv->start); +err_free_priv: + kfree(priv); +err_free_mtdinfo: + kfree(mtdinfo); +err_free_list: + kfree(new_mtd); + return ret; +} + +static void unregister_devices(void) +{ + slram_mtd_list_t *nextitem; + + while (slram_mtdlist) { + nextitem = slram_mtdlist->next; + mtd_device_unregister(slram_mtdlist->mtdinfo); + memunmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start); + kfree(slram_mtdlist->mtdinfo->priv); + kfree(slram_mtdlist->mtdinfo); + kfree(slram_mtdlist); + slram_mtdlist = nextitem; + } +} + +static unsigned long handle_unit(unsigned long value, char *unit) +{ + if ((*unit == 'M') || (*unit == 'm')) { + return(value * 1024 * 1024); + } else if ((*unit == 'K') || (*unit == 'k')) { + return(value * 1024); + } + return(value); +} + +static int parse_cmdline(char *devname, char *szstart, char *szlength) +{ + char *buffer; + unsigned long devstart; + unsigned long devlength; + + if ((!devname) || (!szstart) || (!szlength)) { + unregister_devices(); + return(-EINVAL); + } + + devstart = simple_strtoul(szstart, &buffer, 0); + devstart = handle_unit(devstart, buffer); + + if (*(szlength) != '+') { + devlength = simple_strtoul(szlength, &buffer, 0); + devlength = handle_unit(devlength, buffer); + if (devlength < devstart) + goto err_out; + + devlength -= devstart; + } else { + devlength = simple_strtoul(szlength + 1, &buffer, 0); + devlength = handle_unit(devlength, buffer); + } + T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n", + devname, devstart, devlength); + if (devlength % SLRAM_BLK_SZ != 0) + goto err_out; + + if ((devstart = register_device(devname, devstart, devlength))){ + unregister_devices(); + return((int)devstart); + } + return(0); + +err_out: + E("slram: Illegal length parameter.\n"); + return(-EINVAL); +} + +#ifndef MODULE + +static int __init mtd_slram_setup(char *str) +{ + map = str; + return(1); +} + +__setup("slram=", mtd_slram_setup); + +#endif + +static int __init init_slram(void) +{ + char *devname; + +#ifndef MODULE + char *devstart; + char *devlength; + + if (!map) { + E("slram: not enough parameters.\n"); + return(-EINVAL); + } + while (map) { + devname = devstart = devlength = NULL; + + if (!(devname = strsep(&map, ","))) { + E("slram: No devicename specified.\n"); + break; + } + T("slram: devname = %s\n", devname); + if ((!map) || (!(devstart = strsep(&map, ",")))) { + E("slram: No devicestart specified.\n"); + break; + } + T("slram: devstart = %s\n", devstart); + if ((!map) || (!(devlength = strsep(&map, ",")))) { + E("slram: No devicelength / -end specified.\n"); + break; + } + T("slram: devlength = %s\n", devlength); + if (parse_cmdline(devname, devstart, devlength) != 0) { + return(-EINVAL); + } + } +#else + int count; + int i; + + for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count]; + count++) { + } + + if ((count % 3 != 0) || (count == 0)) { + E("slram: not enough parameters.\n"); + return(-EINVAL); + } + for (i = 0; i < (count / 3); i++) { + devname = map[i * 3]; + + if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) { + return(-EINVAL); + } + + } +#endif /* !MODULE */ + + return(0); +} + +static void __exit cleanup_slram(void) +{ + unregister_devices(); +} + +module_init(init_slram); +module_exit(cleanup_slram); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>"); +MODULE_DESCRIPTION("MTD driver for uncached system RAM"); |
