PCI: aardvark: Do not clear status bits of masked interrupts

stable inclusion
from stable-5.10.80
commit 3bcbace714bb82721a38955b358afd476c800c3b
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3bcbace714bb82721a38955b358afd476c800c3b

--------------------------------

commit a7ca6d7f upstream.

The PCIE_ISR1_REG says which interrupts are currently set / active,
including those which are masked.

The driver currently reads this register and looks if some unmasked
interrupts are active, and if not, it clears status bits of _all_
interrupts, including the masked ones.

This is incorrect, since, for example, some drivers may poll these bits.

Remove this clearing, and also remove this early return statement
completely, since it does not change functionality in any way.

Link: https://lore.kernel.org/r/20211005180952.6812-7-kabel@kernel.org
Fixes: 8c39d710 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NMarek Behún <kabel@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/pci/controller/pci-aardvark.c

@@ -1286,12 +1286,6 @@ static void advk_pcie_handle_int(struct advk_pcie *pcie)
 	isr1_mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
 	isr1_status = isr1_val & ((~isr1_mask) & PCIE_ISR1_ALL_MASK);
 
-	if (!isr0_status && !isr1_status) {
-		advk_writel(pcie, isr0_val, PCIE_ISR0_REG);
-		advk_writel(pcie, isr1_val, PCIE_ISR1_REG);
-		return;
-	}
-
 	/* Process MSI interrupts */
 	if (isr0_status & PCIE_ISR0_MSI_INT_PENDING)
 		advk_pcie_handle_msi(pcie);