forked from Minki/linux
148c87c89e
This patch fixes an interrupt thrash issue with c_can driver. In c_can_isr() function interrupts are disabled and enabled only in c_can_poll() function. c_can_isr() & c_can_poll() both read the irqstatus flag. However, irqstatus is always read as 0 in c_can_poll() because all C_CAN interrupts are disabled in c_can_isr(). This causes all interrupts to be re-enabled in c_can_poll() which in turn causes another interrupt since the event is not really handled. This keeps happening causing a flood of interrupts. To fix this, read the irqstatus register in isr and use the same cached value in the poll function. Cc: stable@kernel.org # 2.6.39+ Signed-off-by: AnilKumar Ch <anilkumar@ti.com> Acked-by: Wolfgang Grandegger <wg@grandegger.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/*
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* CAN bus driver for Bosch C_CAN controller
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*
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* Copyright (C) 2010 ST Microelectronics
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* Bhupesh Sharma <bhupesh.sharma@st.com>
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*
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* Borrowed heavily from the C_CAN driver originally written by:
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* Copyright (C) 2007
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* - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
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* - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
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*
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* Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
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* Bosch C_CAN user manual can be obtained from:
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* http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
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* users_manual_c_can.pdf
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#ifndef C_CAN_H
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#define C_CAN_H
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/* c_can IF registers */
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struct c_can_if_regs {
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u16 com_req;
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u16 com_mask;
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u16 mask1;
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u16 mask2;
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u16 arb1;
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u16 arb2;
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u16 msg_cntrl;
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u16 data[4];
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u16 _reserved[13];
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};
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/* c_can hardware registers */
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struct c_can_regs {
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u16 control;
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u16 status;
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u16 err_cnt;
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u16 btr;
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u16 interrupt;
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u16 test;
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u16 brp_ext;
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u16 _reserved1;
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struct c_can_if_regs ifregs[2]; /* [0] = IF1 and [1] = IF2 */
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u16 _reserved2[8];
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u16 txrqst1;
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u16 txrqst2;
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u16 _reserved3[6];
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u16 newdat1;
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u16 newdat2;
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u16 _reserved4[6];
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u16 intpnd1;
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u16 intpnd2;
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u16 _reserved5[6];
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u16 msgval1;
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u16 msgval2;
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u16 _reserved6[6];
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};
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/* c_can private data structure */
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struct c_can_priv {
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struct can_priv can; /* must be the first member */
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struct napi_struct napi;
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struct net_device *dev;
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int tx_object;
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int current_status;
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int last_status;
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u16 (*read_reg) (struct c_can_priv *priv, void *reg);
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void (*write_reg) (struct c_can_priv *priv, void *reg, u16 val);
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struct c_can_regs __iomem *regs;
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unsigned long irq_flags; /* for request_irq() */
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unsigned int tx_next;
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unsigned int tx_echo;
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void *priv; /* for board-specific data */
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u16 irqstatus;
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};
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struct net_device *alloc_c_can_dev(void);
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void free_c_can_dev(struct net_device *dev);
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int register_c_can_dev(struct net_device *dev);
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void unregister_c_can_dev(struct net_device *dev);
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#endif /* C_CAN_H */
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