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bus: rifsc: fix RIF configuration check for peripherals

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Peripheral holding CID0 cannot be accessed, remove this completely
incorrect check. While there, fix  and simplify the semaphore checking
that should be performed when the CID filtering is enabled.

Fixes: a182084572 ("bus: rifsc: introduce RIFSC firewall controller driver")
Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
Link: https://lore.kernel.org/r/20260129-fix_cid_check_rifsc-v1-1-ef280ccf764d@foss.st.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
This commit is contained in:
Gatien Chevallier 2026-01-29 13:56:17 +01:00 • committed by Alexandre Torgue
commit d5ce3b4e95
1 changed files with 18 additions and 34 deletions
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52
drivers/bus/stm32_rifsc.c
View file

@ -687,34 +687,6 @@ static int stm32_rifsc_grant_access(struct stm32_firewall_controller *ctrl, u32
sec_reg_value = readl(rifsc_controller->mmio + RIFSC_RISC_SECCFGR0 + 0x4 * reg_id);
cid_reg_value = readl(rifsc_controller->mmio + RIFSC_RISC_PER0_CIDCFGR + 0x8 * firewall_id);
/* First check conditions for semaphore mode, which doesn't take into account static CID. */
if ((cid_reg_value & CIDCFGR_SEMEN) && (cid_reg_value & CIDCFGR_CFEN)) {
if (cid_reg_value & BIT(RIF_CID1 + SEMWL_SHIFT)) {
/* Static CID is irrelevant if semaphore mode */
goto skip_cid_check;
} else {
dev_dbg(rifsc_controller->dev,
"Invalid bus semaphore configuration: index %d\n", firewall_id);
return -EACCES;
}
}
/*
* Skip CID check if CID filtering isn't enabled or filtering is enabled on CID0, which
* corresponds to whatever CID.
*/
if (!(cid_reg_value & CIDCFGR_CFEN) ||
FIELD_GET(RIFSC_RISC_SCID_MASK, cid_reg_value) == RIF_CID0)
goto skip_cid_check;
/* Coherency check with the CID configuration */
if (FIELD_GET(RIFSC_RISC_SCID_MASK, cid_reg_value) != RIF_CID1) {
dev_dbg(rifsc_controller->dev, "Invalid CID configuration for peripheral: %d\n",
firewall_id);
return -EACCES;
}
skip_cid_check:
/* Check security configuration */
if (sec_reg_value & BIT(reg_offset)) {
dev_dbg(rifsc_controller->dev,
@ -722,19 +694,31 @@ skip_cid_check:
return -EACCES;
}
/*
* If the peripheral is in semaphore mode, take the semaphore so that
* the CID1 has the ownership.
*/
if ((cid_reg_value & CIDCFGR_SEMEN) && (cid_reg_value & CIDCFGR_CFEN)) {
/* Skip CID check if CID filtering isn't enabled */
if (!(cid_reg_value & CIDCFGR_CFEN))
goto skip_cid_check;
/* First check conditions for semaphore mode, which doesn't take into account static CID. */
if (cid_reg_value & CIDCFGR_SEMEN) {
if (!(cid_reg_value & BIT(RIF_CID1 + SEMWL_SHIFT))) {
dev_dbg(rifsc_controller->dev,
"Invalid bus semaphore configuration: index %d\n", firewall_id);
return -EACCES;
}
rc = stm32_rif_acquire_semaphore(rifsc_controller, firewall_id);
if (rc) {
dev_err(rifsc_controller->dev,
dev_dbg(rifsc_controller->dev,
"Couldn't acquire semaphore for peripheral: %d\n", firewall_id);
return rc;
}
} else if (FIELD_GET(RIFSC_RISC_SCID_MASK, cid_reg_value) != RIF_CID1) {
dev_dbg(rifsc_controller->dev, "Invalid CID configuration for peripheral: %d\n",
firewall_id);
return -EACCES;
}
skip_cid_check:
return 0;
}