From: "Russell King (Oracle)" <rmk+kernel(a)armlinux.org.uk>
The i.MX6 CPU frequency driver sometimes fails to register at boot time
due to nvmem_cell_read_u32() sporadically returning -ENOENT.
This happens because there is a window where __nvmem_device_get() in
of_nvmem_cell_get() is able to return the nvmem device, but as cells
have been setup, nvmem_find_cell_entry_by_node() returns NULL.
The occurs because the nvmem core registration code violates one of the
fundamental principles of kernel programming: do not publish data
structures before their setup is complete.
Fix this by making nvmem core code conform with this principle.
Cc: stable(a)vger.kernel.org
Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers")
Signed-off-by: Russell King (Oracle) <rmk+kernel(a)armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla(a)linaro.org>
---
drivers/nvmem/core.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index ac77a019aed7..e92c6f1aadbb 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -832,22 +832,16 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
nvmem->dev.groups = nvmem_dev_groups;
#endif
- dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
-
- rval = device_add(&nvmem->dev);
- if (rval)
- goto err_put_device;
-
if (nvmem->nkeepout) {
rval = nvmem_validate_keepouts(nvmem);
if (rval)
- goto err_device_del;
+ goto err_put_device;
}
if (config->compat) {
rval = nvmem_sysfs_setup_compat(nvmem, config);
if (rval)
- goto err_device_del;
+ goto err_put_device;
}
if (config->cells) {
@@ -864,6 +858,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
if (rval)
goto err_remove_cells;
+ dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
+
+ rval = device_add(&nvmem->dev);
+ if (rval)
+ goto err_remove_cells;
+
blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
return nvmem;
@@ -873,8 +873,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
err_teardown_compat:
if (config->compat)
nvmem_sysfs_remove_compat(nvmem, config);
-err_device_del:
- device_del(&nvmem->dev);
err_put_device:
put_device(&nvmem->dev);
--
2.25.1
From: "Russell King (Oracle)" <rmk+kernel(a)armlinux.org.uk>
The error path for wp_gpio attempts to free the IDA nvmem->id, but
this has yet to be assigned, so will always be zero - leaking the
ID allocated by ida_alloc(). Fix this by moving the initialisation
of nvmem->id earlier.
Cc: stable(a)vger.kernel.org
Fixes: f7d8d7dcd978 ("nvmem: fix memory leak in error path")
Signed-off-by: Russell King (Oracle) <rmk+kernel(a)armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla(a)linaro.org>
---
drivers/nvmem/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 321d7d63e068..7394a7598efa 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -770,6 +770,8 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
return ERR_PTR(rval);
}
+ nvmem->id = rval;
+
if (config->wp_gpio)
nvmem->wp_gpio = config->wp_gpio;
else if (!config->ignore_wp)
@@ -785,7 +787,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
kref_init(&nvmem->refcnt);
INIT_LIST_HEAD(&nvmem->cells);
- nvmem->id = rval;
nvmem->owner = config->owner;
if (!nvmem->owner && config->dev->driver)
nvmem->owner = config->dev->driver->owner;
--
2.25.1
From: Samuel Holland <samuel(a)sholland.org>
The SID SRAM on at least some SoCs (A64 and D1) returns different values
when read with bus cycles narrower than 32 bits. This is not immediately
obvious, because memcpy_fromio() uses word-size accesses as long as
enough data is being copied.
The vendor driver always uses 32-bit MMIO reads, so do the same here.
This is faster than the register-based method, which is currently used
as a workaround on A64. And it fixes the values returned on D1, where
the SRAM method was being used.
The special case for the last word is needed to maintain .word_size == 1
for sysfs ABI compatibility, as noted previously in commit de2a3eaea552
("nvmem: sunxi_sid: Optimize register read-out method").
Cc: stable(a)vger.kernel.org
Fixes: 07ae4fde9efa ("nvmem: sunxi_sid: Add support for D1 variant")
Tested-by: Heiko Stuebner <heiko(a)sntech.de>
Signed-off-by: Samuel Holland <samuel(a)sholland.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla(a)linaro.org>
---
drivers/nvmem/sunxi_sid.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
index 5750e1f4bcdb..92dfe4cb10e3 100644
--- a/drivers/nvmem/sunxi_sid.c
+++ b/drivers/nvmem/sunxi_sid.c
@@ -41,8 +41,21 @@ static int sunxi_sid_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct sunxi_sid *sid = context;
+ u32 word;
+
+ /* .stride = 4 so offset is guaranteed to be aligned */
+ __ioread32_copy(val, sid->base + sid->value_offset + offset, bytes / 4);
- memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes);
+ val += round_down(bytes, 4);
+ offset += round_down(bytes, 4);
+ bytes = bytes % 4;
+
+ if (!bytes)
+ return 0;
+
+ /* Handle any trailing bytes */
+ word = readl_relaxed(sid->base + sid->value_offset + offset);
+ memcpy(val, &word, bytes);
return 0;
}
--
2.25.1