[PATCH v7 06/14] PCI: rzg3s-host: Drop read-modify-write approach for the R/W1C registers

[Claudiu Beznea <claudiu.beznea@kernel.org>]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The AXI registers PCI_PINTRCVIS and PCI_PINTRCVIS_MSI are R/W1C. According
to the RZ/G3S HW manual, Rev. 1.30, R/W1C means "it can be cleared to 0b by
writing 1b. Writing 0b does not change anything."

Drop the read-modify-write approach and make use of this hardware
capability. This avoids clearing unwanted interrupts.

Fixes: 7ef502fb35b2 ("PCI: Add Renesas RZ/G3S host controller driver")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v7:
- none, this patch is new

 drivers/pci/controller/pcie-rzg3s-host.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/pcie-rzg3s-host.c b/drivers/pci/controller/pcie-rzg3s-host.c
index 94345d6f0bee..b0a150262959 100644
--- a/drivers/pci/controller/pcie-rzg3s-host.c
+++ b/drivers/pci/controller/pcie-rzg3s-host.c
@@ -82,6 +82,7 @@
 #define RZG3S_PCI_MSGRCVIE			0x120
 #define RZG3S_PCI_MSGRCVIE_MSG_RCV		BIT(24)
 
+/* Register is R/W1C, it doesn't require locking. */
 #define RZG3S_PCI_MSGRCVIS			0x124
 #define RZG3S_PCI_MSGRCVIS_MRI			BIT(24)
 
@@ -591,11 +592,10 @@ static irqreturn_t rzg3s_pcie_msi_irq(int irq, void *data)
 		return IRQ_NONE;
 
 	/* Clear the MSI */
-	rzg3s_pcie_update_bits(host->axi, RZG3S_PCI_PINTRCVIS,
-			       RZG3S_PCI_PINTRCVIS_MSI,
-			       RZG3S_PCI_PINTRCVIS_MSI);
-	rzg3s_pcie_update_bits(host->axi, RZG3S_PCI_MSGRCVIS,
-			       RZG3S_PCI_MSGRCVIS_MRI, RZG3S_PCI_MSGRCVIS_MRI);
+	writel_relaxed(RZG3S_PCI_PINTRCVIS_MSI,
+		       host->axi + RZG3S_PCI_PINTRCVIS);
+	writel_relaxed(RZG3S_PCI_MSGRCVIS_MRI,
+		       host->axi + RZG3S_PCI_MSGRCVIS);
 
 	for (u8 reg_id = 0; reg_id < regs; reg_id++) {
 		status = readl_relaxed(host->axi + RZG3S_PCI_MSIRS(reg_id));
@@ -958,9 +958,8 @@ static void rzg3s_pcie_intx_irq_ack(struct irq_data *d)
 {
 	struct rzg3s_pcie_host *host = irq_data_get_irq_chip_data(d);
 
-	rzg3s_pcie_update_bits(host->axi, RZG3S_PCI_PINTRCVIS,
-			       RZG3S_PCI_PINTRCVIS_INTX(d->hwirq),
-			       RZG3S_PCI_PINTRCVIS_INTX(d->hwirq));
+	writel_relaxed(RZG3S_PCI_PINTRCVIS_INTX(d->hwirq),
+		       host->axi + RZG3S_PCI_PINTRCVIS);
 }
 
 static void rzg3s_pcie_intx_irq_mask(struct irq_data *d)
-- 
2.43.0