From: Arnaud Pouliquen arnaud.pouliquen@st.com
commit dba9a3dfe912dc47c9dbc9ba1f5f65adbf9aea0f upstream.
Add spinlock protection on IPCC register update to avoid race condition. Without this fix, stm32_ipcc_set_bits and stm32_ipcc_clr_bits can be called in parallel for different channels. This results in register corruptions.
Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@st.com Reviewed-by: Fabien Dessenne fabien.dessenne@st.com Signed-off-by: Jassi Brar jaswinder.singh@linaro.org Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/mailbox/stm32-ipcc.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-)
--- a/drivers/mailbox/stm32-ipcc.c +++ b/drivers/mailbox/stm32-ipcc.c @@ -50,6 +50,7 @@ struct stm32_ipcc { void __iomem *reg_base; void __iomem *reg_proc; struct clk *clk; + spinlock_t lock; /* protect access to IPCC registers */ int irqs[IPCC_IRQ_NUM]; int wkp; u32 proc_id; @@ -58,14 +59,24 @@ struct stm32_ipcc { u32 xmr; };
-static inline void stm32_ipcc_set_bits(void __iomem *reg, u32 mask) +static inline void stm32_ipcc_set_bits(spinlock_t *lock, void __iomem *reg, + u32 mask) { + unsigned long flags; + + spin_lock_irqsave(lock, flags); writel_relaxed(readl_relaxed(reg) | mask, reg); + spin_unlock_irqrestore(lock, flags); }
-static inline void stm32_ipcc_clr_bits(void __iomem *reg, u32 mask) +static inline void stm32_ipcc_clr_bits(spinlock_t *lock, void __iomem *reg, + u32 mask) { + unsigned long flags; + + spin_lock_irqsave(lock, flags); writel_relaxed(readl_relaxed(reg) & ~mask, reg); + spin_unlock_irqrestore(lock, flags); }
static irqreturn_t stm32_ipcc_rx_irq(int irq, void *data) @@ -92,7 +103,7 @@ static irqreturn_t stm32_ipcc_rx_irq(int
mbox_chan_received_data(&ipcc->controller.chans[chan], NULL);
- stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XSCR, + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR, RX_BIT_CHAN(chan));
ret = IRQ_HANDLED; @@ -121,7 +132,7 @@ static irqreturn_t stm32_ipcc_tx_irq(int dev_dbg(dev, "%s: chan:%d tx\n", __func__, chan);
/* mask 'tx channel free' interrupt */ - stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR, + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR, TX_BIT_CHAN(chan));
mbox_chan_txdone(&ipcc->controller.chans[chan], 0); @@ -141,10 +152,12 @@ static int stm32_ipcc_send_data(struct m dev_dbg(ipcc->controller.dev, "%s: chan:%d\n", __func__, chan);
/* set channel n occupied */ - stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XSCR, TX_BIT_CHAN(chan)); + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR, + TX_BIT_CHAN(chan));
/* unmask 'tx channel free' interrupt */ - stm32_ipcc_clr_bits(ipcc->reg_proc + IPCC_XMR, TX_BIT_CHAN(chan)); + stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR, + TX_BIT_CHAN(chan));
return 0; } @@ -163,7 +176,8 @@ static int stm32_ipcc_startup(struct mbo }
/* unmask 'rx channel occupied' interrupt */ - stm32_ipcc_clr_bits(ipcc->reg_proc + IPCC_XMR, RX_BIT_CHAN(chan)); + stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR, + RX_BIT_CHAN(chan));
return 0; } @@ -175,7 +189,7 @@ static void stm32_ipcc_shutdown(struct m controller);
/* mask rx/tx interrupt */ - stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR, + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR, RX_BIT_CHAN(chan) | TX_BIT_CHAN(chan));
clk_disable_unprepare(ipcc->clk); @@ -208,6 +222,8 @@ static int stm32_ipcc_probe(struct platf if (!ipcc) return -ENOMEM;
+ spin_lock_init(&ipcc->lock); + /* proc_id */ if (of_property_read_u32(np, "st,proc-id", &ipcc->proc_id)) { dev_err(dev, "Missing st,proc-id\n"); @@ -259,9 +275,10 @@ static int stm32_ipcc_probe(struct platf }
/* mask and enable rx/tx irq */ - stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR, + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR, RX_BIT_MASK | TX_BIT_MASK); - stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XCR, XCR_RXOIE | XCR_TXOIE); + stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR, + XCR_RXOIE | XCR_TXOIE);
/* wakeup */ if (of_property_read_bool(np, "wakeup-source")) {