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usb: atm: cxacru: Merge cxacru_upload_firmware() into cxacru_heavy_init()

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After a recent change in clang to expose uninitialized warnings from
const variables [1], there is a warning in cxacru_heavy_init():

  drivers/usb/atm/cxacru.c:1104:6: error: variable 'bp' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
   1104 |         if (instance->modem_type->boot_rom_patch) {
        |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  drivers/usb/atm/cxacru.c:1113:39: note: uninitialized use occurs here
   1113 |         cxacru_upload_firmware(instance, fw, bp);
        |                                              ^~
  drivers/usb/atm/cxacru.c:1104:2: note: remove the 'if' if its condition is always true
   1104 |         if (instance->modem_type->boot_rom_patch) {
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  drivers/usb/atm/cxacru.c:1095:32: note: initialize the variable 'bp' to silence this warning
   1095 |         const struct firmware *fw, *bp;
        |                                       ^
        |                                        = NULL

While the warning is technically correct that bp is conditionally passed
uninitialized to cxacru_upload_firmware(), it is ultimately a false
positive warning on the uninitialized use of bp because the same
condition that initializes bp, instance->modem_type->boot_rom_patch, is
the same one that gates the use of bp within cxacru_upload_firmware().
As this warning occurs in clang's frontend before inlining occurs, it
cannot know that these conditions are indentical to avoid the warning.

Manually inline cxacru_upload_firmware() into cxacru_heavy_init(), as
that is its only callsite, so that clang can see that bp is initialized
and used under the same condition, clearing up the warning without any
functional changes to the code (LLVM was already doing this inlining
later).

Cc: stable@vger.kernel.org
Fixes: 1b0e614652 ("[PATCH] USB ATM: driver for the Conexant AccessRunner chipset cxacru")
Closes: https://github.com/ClangBuiltLinux/linux/issues/2102
Link: 2464313eef [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250722-usb-cxacru-fix-clang-21-uninit-warning-v2-1-6708a18decd2@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nathan Chancellor 2025-07-22 12:11:18 -07:00 • committed by Greg Kroah-Hartman
parent fcb476990b
commit 8d1b02e5d7
1 changed files with 82 additions and 90 deletions
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172
drivers/usb/atm/cxacru.c
View file

@ -980,94 +980,6 @@ cleanup:
return ret;
}
static void cxacru_upload_firmware(struct cxacru_data *instance,
const struct firmware *fw,
const struct firmware *bp)
{
int ret;
struct usbatm_data *usbatm = instance->usbatm;
struct usb_device *usb_dev = usbatm->usb_dev;
__le16 signature[] = { usb_dev->descriptor.idVendor,
usb_dev->descriptor.idProduct };
__le32 val;
usb_dbg(usbatm, "%s\n", __func__);
/* FirmwarePllFClkValue */
val = cpu_to_le32(instance->modem_type->pll_f_clk);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, PLLFCLK_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "FirmwarePllFClkValue failed: %d\n", ret);
return;
}
/* FirmwarePllBClkValue */
val = cpu_to_le32(instance->modem_type->pll_b_clk);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, PLLBCLK_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "FirmwarePllBClkValue failed: %d\n", ret);
return;
}
/* Enable SDRAM */
val = cpu_to_le32(SDRAM_ENA);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, SDRAMEN_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "Enable SDRAM failed: %d\n", ret);
return;
}
/* Firmware */
usb_info(usbatm, "loading firmware\n");
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, FW_ADDR, fw->data, fw->size);
if (ret) {
usb_err(usbatm, "Firmware upload failed: %d\n", ret);
return;
}
/* Boot ROM patch */
if (instance->modem_type->boot_rom_patch) {
usb_info(usbatm, "loading boot ROM patch\n");
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, BR_ADDR, bp->data, bp->size);
if (ret) {
usb_err(usbatm, "Boot ROM patching failed: %d\n", ret);
return;
}
}
/* Signature */
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, SIG_ADDR, (u8 *) signature, 4);
if (ret) {
usb_err(usbatm, "Signature storing failed: %d\n", ret);
return;
}
usb_info(usbatm, "starting device\n");
if (instance->modem_type->boot_rom_patch) {
val = cpu_to_le32(BR_ADDR);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, BR_STACK_ADDR, (u8 *) &val, 4);
} else {
ret = cxacru_fw(usb_dev, FW_GOTO_MEM, 0x0, 0x0, FW_ADDR, NULL, 0);
}
if (ret) {
usb_err(usbatm, "Passing control to firmware failed: %d\n", ret);
return;
}
/* Delay to allow firmware to start up. */
msleep_interruptible(1000);
usb_clear_halt(usb_dev, usb_sndbulkpipe(usb_dev, CXACRU_EP_CMD));
usb_clear_halt(usb_dev, usb_rcvbulkpipe(usb_dev, CXACRU_EP_CMD));
usb_clear_halt(usb_dev, usb_sndbulkpipe(usb_dev, CXACRU_EP_DATA));
usb_clear_halt(usb_dev, usb_rcvbulkpipe(usb_dev, CXACRU_EP_DATA));
ret = cxacru_cm(instance, CM_REQUEST_CARD_GET_STATUS, NULL, 0, NULL, 0);
if (ret < 0) {
usb_err(usbatm, "modem failed to initialize: %d\n", ret);
return;
}
}
static int cxacru_find_firmware(struct cxacru_data *instance,
char *phase, const struct firmware **fw_p)
@ -1094,8 +1006,14 @@ static int cxacru_heavy_init(struct usbatm_data *usbatm_instance,
{
const struct firmware *fw, *bp;
struct cxacru_data *instance = usbatm_instance->driver_data;
int ret = cxacru_find_firmware(instance, "fw", &fw);
struct usbatm_data *usbatm = instance->usbatm;
struct usb_device *usb_dev = usbatm->usb_dev;
__le16 signature[] = { usb_dev->descriptor.idVendor,
usb_dev->descriptor.idProduct };
__le32 val;
int ret;
ret = cxacru_find_firmware(instance, "fw", &fw);
if (ret) {
usb_warn(usbatm_instance, "firmware (cxacru-fw.bin) unavailable (system misconfigured?)\n");
return ret;
@ -1110,8 +1028,82 @@ static int cxacru_heavy_init(struct usbatm_data *usbatm_instance,
}
}
cxacru_upload_firmware(instance, fw, bp);
/* FirmwarePllFClkValue */
val = cpu_to_le32(instance->modem_type->pll_f_clk);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, PLLFCLK_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "FirmwarePllFClkValue failed: %d\n", ret);
goto done;
}
/* FirmwarePllBClkValue */
val = cpu_to_le32(instance->modem_type->pll_b_clk);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, PLLBCLK_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "FirmwarePllBClkValue failed: %d\n", ret);
goto done;
}
/* Enable SDRAM */
val = cpu_to_le32(SDRAM_ENA);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, SDRAMEN_ADDR, (u8 *) &val, 4);
if (ret) {
usb_err(usbatm, "Enable SDRAM failed: %d\n", ret);
goto done;
}
/* Firmware */
usb_info(usbatm, "loading firmware\n");
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, FW_ADDR, fw->data, fw->size);
if (ret) {
usb_err(usbatm, "Firmware upload failed: %d\n", ret);
goto done;
}
/* Boot ROM patch */
if (instance->modem_type->boot_rom_patch) {
usb_info(usbatm, "loading boot ROM patch\n");
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, BR_ADDR, bp->data, bp->size);
if (ret) {
usb_err(usbatm, "Boot ROM patching failed: %d\n", ret);
goto done;
}
}
/* Signature */
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, SIG_ADDR, (u8 *) signature, 4);
if (ret) {
usb_err(usbatm, "Signature storing failed: %d\n", ret);
goto done;
}
usb_info(usbatm, "starting device\n");
if (instance->modem_type->boot_rom_patch) {
val = cpu_to_le32(BR_ADDR);
ret = cxacru_fw(usb_dev, FW_WRITE_MEM, 0x2, 0x0, BR_STACK_ADDR, (u8 *) &val, 4);
} else {
ret = cxacru_fw(usb_dev, FW_GOTO_MEM, 0x0, 0x0, FW_ADDR, NULL, 0);
}
if (ret) {
usb_err(usbatm, "Passing control to firmware failed: %d\n", ret);
goto done;
}
/* Delay to allow firmware to start up. */
msleep_interruptible(1000);
usb_clear_halt(usb_dev, usb_sndbulkpipe(usb_dev, CXACRU_EP_CMD));
usb_clear_halt(usb_dev, usb_rcvbulkpipe(usb_dev, CXACRU_EP_CMD));
usb_clear_halt(usb_dev, usb_sndbulkpipe(usb_dev, CXACRU_EP_DATA));
usb_clear_halt(usb_dev, usb_rcvbulkpipe(usb_dev, CXACRU_EP_DATA));
ret = cxacru_cm(instance, CM_REQUEST_CARD_GET_STATUS, NULL, 0, NULL, 0);
if (ret < 0) {
usb_err(usbatm, "modem failed to initialize: %d\n", ret);
goto done;
}
done:
if (instance->modem_type->boot_rom_patch)
release_firmware(bp);
release_firmware(fw);