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mailbox: stm32_ipcc: add spinlock to fix channels concurrent access 

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>
This commit is contained in:
Arnaud Pouliquen 2019-05-22 10:25:35 +02:00 committed by Jassi Brar
parent 6fbc7275c7
commit dba9a3dfe9
1 changed files with 27 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/mailbox/stm32-ipcc.c
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@ -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 irq, void *data)
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 irq, void *data)
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 mbox_chan *link, void *data)
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 mbox_chan *link)
}
/* 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 mbox_chan *link)
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 platform_device *pdev)
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 platform_device *pdev)
}
/* 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")) {