From da8fa9cca5b760cb8e5ab16ce7e1941cfc3e04cc Mon Sep 17 00:00:00 2001 From: Doug Berger Date: Wed, 21 Jun 2017 16:20:14 -0700 Subject: [PATCH] ata: ahci_brcm: Avoid writing to read-only registers This commit makes use of the AHCI_HFLAG_YES_ALPM flag to prevent the driver from writing to the read-only Host Capability register. It also sets the AHCI_HFLAG_NO_WRITE_TO_RO flag to prevent the AHCI library from writing to read-only registers. Signed-off-by: Doug Berger Signed-off-by: Tejun Heo --- drivers/ata/ahci_brcm.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/ata/ahci_brcm.c b/drivers/ata/ahci_brcm.c index 6f8a7341fa08..5936d1679bf3 100644 --- a/drivers/ata/ahci_brcm.c +++ b/drivers/ata/ahci_brcm.c @@ -39,7 +39,6 @@ #define PIODATA_ENDIAN_SHIFT 6 #define ENDIAN_SWAP_NONE 0 #define ENDIAN_SWAP_FULL 2 - #define OVERRIDE_HWINIT BIT(16) #define SATA_TOP_CTRL_TP_CTRL 0x8 #define SATA_TOP_CTRL_PHY_CTRL 0xc #define SATA_TOP_CTRL_PHY_CTRL_1 0x0 @@ -126,17 +125,13 @@ static inline void brcm_sata_writereg(u32 val, void __iomem *addr) static void brcm_sata_alpm_init(struct ahci_host_priv *hpriv) { struct brcm_ahci_priv *priv = hpriv->plat_data; - u32 bus_ctrl, port_ctrl, host_caps; + u32 port_ctrl, host_caps; int i; /* Enable support for ALPM */ - bus_ctrl = brcm_sata_readreg(priv->top_ctrl + - SATA_TOP_CTRL_BUS_CTRL); - brcm_sata_writereg(bus_ctrl | OVERRIDE_HWINIT, - priv->top_ctrl + SATA_TOP_CTRL_BUS_CTRL); host_caps = readl(hpriv->mmio + HOST_CAP); - writel(host_caps | HOST_CAP_ALPM, hpriv->mmio); - brcm_sata_writereg(bus_ctrl, priv->top_ctrl + SATA_TOP_CTRL_BUS_CTRL); + if (!(host_caps & HOST_CAP_ALPM)) + hpriv->flags |= AHCI_HFLAG_YES_ALPM; /* * Adjust timeout to allow PLL sufficient time to lock while waking @@ -360,6 +355,7 @@ static int brcm_ahci_probe(struct platform_device *pdev) if (priv->quirks & BRCM_AHCI_QUIRK_NO_NCQ) hpriv->flags |= AHCI_HFLAG_NO_NCQ; + hpriv->flags |= AHCI_HFLAG_NO_WRITE_TO_RO; ret = ahci_platform_init_host(pdev, hpriv, &ahci_brcm_port_info, &ahci_platform_sht); -- 2.20.1